# Advice on mini-splits



## Wear More Layers

Hi.  I was investigating pellet stoves and wood stoves as an alternative to oil heat when members of the Hearth Room brought mini-split heat pumps to my attention. I did a little homework and had 3 companies come out to give me estimates.  Their solutions and prices are so different from one another that I don't know where to turn next.  Below are details:

my home: 1,300 sq ft, 2 story, built in 1950s

Company #1 solution:  2 downstairs units + 2 upstairs (1 per bedroom); total of 36,000 Btus; cost = $12,350 after $250 utility company rebate; ineligible for tax credit

Company # 2 solution: 1 downstairs + 2 upstairs (1 per bedroom);  total of 42,000 Btus; cost = $9,300; ineligible for utility company rebate or tax credit

Company #3 solution: 1 downstairs + 1 upstairs (in hallway pointing at bedrooms); total of 24,000 Btus; cost = $6,300 after $250 utility rebate and $300 tax credit

Each company uses Mitsubishi units, and each is charging me ~$3,100/unit after rebates/tax credits.  How many units and how many Btus do I really need?  Are the prices reasonable?  If you have advice, I'd love to hear from you.


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## DBoon

Hi Wear More Layers, welcome to the site. 

I just put in a Fujitsu mini-split.  I had Mitsubishi units quoted as well, but they were priced higher by the installers around my parts. 

It would be hard to estimate your BTU needs from the info you provided.  Can you provide more info about your house?  How much insulation in the attic and walls?  How good are your windows?  Does your home feel drafty?  How much oil did you burn last year and what temperature do you keep your house?  

Also, if you have few people in your house and the doors are mostly open to the rooms, you might find that company #3 solution is the right way to go, provided your heating needs aren't too high.  Heat will travel.  You can always add more later.  You might even want to start with just one downstairs for the moment and see how that works for you - at the very least, it will reduce your oil consumption a great deal, and you can add more later.


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## begreen

The first thing to do is look at your old heating bills. Go back at least a few years. Take the total heating fuel consumption from Dec thru Jan. for each year, then average these numbers. Now divide that number by 62, then by 24. That will give you an average fuel consumption per hour during winter. Then convert that consumption to btus by mulitplying gallons of oil or therms of gas times the corresponding amount of btus in that fuel. That will provide the average btus per hour your house uses in winter. 

Other things to check. Are they installing Mitsubishi Hyper Heat units? That is what you'll want in CT. But they are only available in single head units. It could be that you choose plan #3, but by the heat calcs come up with needing a larger downstairs unit. Whether one or two is better will depend on how open the floorplan is downstairs. If it is not open it may take two units or a dual-head unit. Upstairs is a bit harder to call. Are the bedroom doors normally left open or closed? If open, a hallway unit could be fine. If not, a head unit in each bedroom may work out better.


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## peakbagger

Single unit Mitsubishi Hyper heats are $1,600 on ebay with about $200 to $300 other installation accessories (tubing and plastic gutter to cover the tubing). I built my own support rack so that would be additional (I would guess $50). I had a breaker and wiring. So the installer is receiving $1100 for installation time. I expect with the right tools a tech and a helper can do an install in 4 hour average (more for second story and less for 1st floor). I would ask if they are doing the wiring or if that is separate as most hvac techs don't have electricians licenses. I don't know why but Mitisubishi doesn't make a hyper heat unit dual head and my understanding is dul head units don't have the low temperature efficiency.

One thing to keep in mind is that few folks would have 8 breaker spaces in their house electrical panel. If your panel is rated for split breakers you may get away needed in 4 full size. There is a good chance that you may have put in subpanel if you have a 200 amp panel and if you have a 100 amp service, you probably need an upgrade to 200 amp.  This could add $1 to 2K to the project.


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## DBoon

begreen said:


> Are they installing Mitsubishi Hyper Heat units? That is what you'll want in CT.


I would second the advice the get the Mitsubishi hyper heat units.  I got the Fujitsu equivalent, and they do a great job of putting the heat out even at ridiculously low temperatures.


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## Wear More Layers

DBoon said:


> I would second the advice the get the Mitsubishi hyper heat units.  I got the Fujitsu equivalent, and they do a great job of putting the heat out even at ridiculously low temperatures.



None of the 3 companies recommended Hyper Heat units.  Someone else on hearth.com in the Hearth Room told me I didn't need Hyper Heat given my location in southern CT.   I'm ok with kicking the oil heat on at very low temps because it will cost less to do that than to buy separate outdoor units for each Hyper Heat installation.

I don't have the skills necessary to install the units myself; hence the need to find a company to do it for me.  I did consider purchasing everything online, but Mitsubishi and Fujitsu apparently don't offer warranties on web purchases.  

All of the companies looked at my electric panel and indicated that their electricians could handle the job without issue.

As for heat use in my house:  the windows were installed within the past 15 years and are doubel-paned.  The walls are insulated, but I don't know how well.  The attic is insulated but not ideally.  Energy auditors tried sealing as many small leaks in the house as they could find, and I don't feel any drafts in winter. 

I keep the house cool (mid-50s) during the day and "crank" it to 58 at night.  That's frankly just a tad too cold for me.  I'd like it to be in the low 60s.  The downstairs is fairly open, and two of the three companies thought that one strategically placed unit could heat the whole 1st floor. The upstairs has 2 bedrooms plus an office and bath.  I keep all of the doors open, which is why one company thought a hallway unit could heat everything. The other companies thought that at least the master bedroom needed its own unit.

I'm too tired to do math at the moment and will run the numbers suggested by begreen tomorrow.

Thanks for everyone's helpful comments.


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## woodgeek

I suspect the installers, in addition to wanting to sell you as much hardware as possible, do NOT want you to call back and complain that you don't have enough BTUs.  You still have the oil backup system to 'top off' the heat on very cold days (you would set the oil stat a couple deg below the minis, and it would only come on when the minis were wallowing).

Yeah.  Bottom line is that HPs or minis cost a lot per BTU capacity. Even more for Hyper-Heat.  With a furnace, a slightly bigger burner is a small upcharge, so you oversize with a safety factor with a demand based on square footage or other estimates.  With a HP, you do not want to pay for too much capacity.

If money was very tight (doesn't sound like this is the case), I would install 1 downstairs.  It would take a big bite out of oil/wood usage, would carry the house in the shoulder seasons (if natural circ upstairs was not an issue) and would have good payback.

If money was not super tight I would do two units, one up one down.  You get some zonal heat/AC control (I wish I had that with my 1 zone system) and more heat overall.  More than 2 sounds kinda nuts to me.....I think those installers are worried about distribution, and you have addressed that and are not concerned.

Now to get technical......

*1.* let's figure out what your **average** BTU/h load is during January.  If that is 24 kBTU/h, then Plan 3 is prob a good fit.  If it is 36, then I would still prob go with installer #3 (I like his logic), but talk to him about getting bigger units (there are many sizes).  Installation on bigger units will prob be the same as on smaller units (bigger units will give you more BTU/$$ installed)
*2.* get the specific part numbers the installer intends, and I will try to look up detailed specs. The '12k BTU' size mini that is a nominal value that depends on outside temp.  We can look up performance tables and verify that is will provide the BTUs you need at average Jan temps.
*3. *Send $$/kWh from your utility and I will estimate savings/ROI.

PS: The folks pushing the '100% heating capacity at XX°F' are in my opinion selling snake oil.  All HPs run on refrigerant, and the volatility (vapor pressure) of the refrigerant goes down with decreasing temp, so the BTU/h goes down too.  This is not a design flaw for HPs, it is physical chemistry.  The units that 'deliver 100%' down to some temp are just being throttled down above that temp.  Duh.  All you care about it that the BTUs delivered on an average Jan day meet your needs.  All minis will throttle down above that (which is nice, since they will run quieter and more eff then).  The Hyper Heat units are nice, and if I lived North of Boston climate-wise, I would research them.  If you are in the lowlands in southern CT, with a roughly NYC climate, you don't need to go there.


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## Justin M

If you keep the doors open and you like it cool anyway you will be fine with 2 units.  They take a while to recover, so you wouldn't want to do too big of a set back during the day.  It's more of a set it and forget it thing, but they are cheap to run so that's not a big deal.  On my Mitsubishi multi-unit setup there is a minimum heat set point of 68°.  If I set it to anything lower it will still heat to 68°.  I'm not sure why they would design it that way.   So that's one other thing to look in to since you like it cool.


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## woodgeek

OK, found the other thread..... https://www.hearth.com/talk/threads/head-spinning-pellet-or-wood.117232/page-4#post-1577722

we already estimated cost per MMBTU.

You say you use <600 gals/year and keep the stat at more like 58° than (typical) 70°F. We need to estimate your demand at something warmer, like 68-70°F.

If your climate is 5000 heating degree days (HDD) like NYC, that assumes a stat setting of 70°F and a 'base temp' of 65°F.  (other heat source like appliances, body heat and passive solar would heat your house 5°F above outside temps). Your base temp is prob more like 53°F rather than 65, so you are saving 12 HDD's per day * 150 heating days = 1800 HDDs, so maybe your usage is 1800/5000 = 36% lower than it would have been with a 70° setpoint.

Estimated another way...each degree you setback saves you 1% for an 8 hour setback, or 3% for a 24 hour setback (rule of thumb).  You are setting down 12°F, so you are saving 36% by wearing long-johns and a sweater.

So, I still need more info....are you running that oil heater over the summer, and are you using it for hot water??  If the answer to both is yes, then you are likely using 150 gallons for DHW and summer standby, and only 450 gallons for heat.  If you have a elec water heater and shut the oil off in the summer, then you are using 600 gallons for heat.  This is a 25% uncertainty.  I will do both cases.

Case 1: 450 gallons for 58°F stat setpoint....  at 70°F setpoint, this would be 450/0.63 = 714 gallons = 75 MMBTU for 5000 HDD (base 65).  This means your demand is 15000 BTU/HDD.  On a January day when the average temp was 28°F, that is 42 HDDs or 15000*42/24(hrs/day) = *26.3 kBTU/h @ 28°F outside.*

Case 2: Same calculation, but assume 600 gallons:  Final figure is 26.3 * 600/450 = *35 kBTU/h @ 28°F outside.*

So, if the 600 gallons includes summer standby and DHW, then your 3rd quote system (if the nominal BTUs are accurate) will be able to carry your house down to 29-30°F, and likely carry 80+% of your total seasonal heating needs. 

In the other case, your oil system will need to help out whenever the temp outside gets below ~40°F or so.  This would still save enough money (>50% of your oil usage at 70°F stat setting) to make things worthwhile. I would still go with 2 minis, but try to upsize one or both to get closer to 36 kBTU nominal at 25°F.  Of course, if the installer could get you three 12 k minis installed for the price of 2 18k minis, that would be great (but I think that unlikely).


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## flyingcow

I have 2 mitsu  hyper's. An 18kbtu down stairs and a 12kbtu upstairs. The 18 kicks out some serious heat. I have a 2 story/1800sqft house on a hill in northern maine. Avg insulation. I was going to put a 9k in the upstairs, but the cost was the same as a 12k unit. And they performed equally.  When we use the 18k unit, we leave the doors open upstairs(the upstairs HP is turned off). If I set the unit at 70f and it's 20f outside, leave it alone for the day, it heats the whole house pretty damn easy. My guess is a 12k unit would have done the job too.

I also think you might want to try one downstairs, then do the upstairs unit later. Also, if you're keeping your house at a "high" of 58, any more of a setback during the day might not help.

_*Look at the specs of these units.*_ Find out how low you can put your heat settings. My 18k unit only goes down to 68 or 70f. I called Mitsu directly with a few questions. Very easy to talk to and took the time to answer my questions. It's worth your time to call them directly. They have very good customer service.

This is what Mitsu gave me for energy consumption of my 18k unit.  

Cooling  mode uses 1270 watts
                                                                                                              Heating mode outside air at 47f uses 1540 watts
                                                                                                              heating mode outside air at 17f uses 2620 watts.


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## woodgeek

Great advice....having the bigger unit downstairs makes good sense since warm air rises.  You will want the AC function upstairs, but the BTU load in AC will be a lot lower.


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## Wear More Layers

I don't use heat from April to early November, but I do use oil year-round for hot water, so I think Case 1 from wood geek is a more accurate estimate.

The company that suggested 2 units proposed:
MXZ-2B20NA 2 port outdoor unit
MSZ-GE12NA indoor unit, one on each floor

The company that suggest 3 units proposed:
MXZ4B36NA-1 outdoor unit
MSZ-GE24NA indoor unit downstairs
MSZ-GE09NA-8 in each upstairs bedroom.

My cost for electricity is $.182/kWh.


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## woodgeek

Ok.  Took a quick look at specs.   I didn't find any real detailed info.

The quoted 2 zone system has one outdoor unit and 2 indoor units.

A selection guide can be found here....
http://www.mitsubishicomfort.com/en...ons/product-showcase/outdoor-multi-zone-units

It suggests that the quoted system maxes out at 22 kBTU/h, which is a bit short of the estimated 26 kBTU/h loss at typical Jan average temps (28°C) estimated above.

What if you wanted to upsize?
You could upsize the outdoor unit from the MXZ-2B20NA to the MXZ-3B24NA, the 'next size up'.
The latter unit (see link above) claims output up to 34 kBTU/h, above your Jan demand.

The quoted system looks like $2790 for the hardware....
https://www.acwholesalers.com/Mitsu...ump/19673.ac?gclid=CPGsu626oLsCFYQ7OgodnCYAeQ
The upsize system is $3600
https://www.acwholesalers.com/Mitsu...-Pump/19715.ac?catId=cat1034&mainCat=&subCat=
If we assume the install and lineset is the same price, this is a roughly $800-$1k upgrade to get a system that nominally puts out 50% more BTUs.

we need to be careful with nominal numbers....actual output will be lower than peak output by 10-20% due to defrost cycling....Are these numbers including defrost losses (I would guess not).  At what temp is the nominal output achieved?  Couldn't find that out, but probably around freezing (ok for our calculation).  But this argues towards having a little margin.  Maybe your installer knows?

Now, the quoted 2-ton system would def take a big bite out of your oil consumption and would likely carry you whenever the weather was above freezing, but it would need the oil to help out otherwise.  Of course, even in cold weather it would be supplying 70-80% of your needs, so it would still saving you oil then.
In comparison the upsize system might be able to carry you solo 90% of the time. During milder weather it would run slightly more efficient and quieter.

A few issues....
--I suspect the smaller system + oil would be more comfortable.  As optimistic as you are about distribution, the perimeter of your house will get cold during cold weather.  Putting 10-20% of your BTU into the baseboards won't cost a lot, but will even out that cold perimeter nicely.
--The oil system has standby losses of 2-3 kBTU/h whether it circulates or not.  That will help the smaller system to carry to lower temps w/o circulation.
--if you were planning on ditching the oil system at some point in the coming years (i.e. it is old, you don't like the DHW service), then you would be in for a cost down the road of a elec water heater (which by saving you oil standby would be cheaper to operate despite your spendy elec) and some sort of backup for the minis, either new elec baseboards, or better, an 'elec boiler' with your existing baseboards.  That would cost more per BTU than your existing mini_oil setup, but if the mini was powerful enough, the need for backup would be negligible cost.  If you are hating the oil, get the upsized system.
--If you are planning some sig energy audit/ energy eff upgrades to your house, the smaller system might make more sense.  It will save a ton of oil right from the start, and will be 'right sized' for a future better sealed version of your house.  Such an audit will help with the distribution/comfort issue.
--You need to contact you utility to see if you can get cheaper elec in the winter as a heating customer.  I didn't do this until after I installed my HP.  Turns out I got a 50% discount (!).  That is phased out now, but you will wnat to know one way or another.

--Couldn't find out about the min setpoinf of 68°F.  That would tick me off, ask your installer.


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## woodgeek

Ok.  After a little more consideration, I have to say it comes down to your future plans and current desires.  You can def get a system that saves oil, and whether you knock down the oil 70% or 85% doesn't really matter as far as the decision is concerned.  More important is comfort and future options.  I am not worried about your open plan downstairs, but I am more worried about your bedrooms upstairs.  Maybe you are happy leaving the doors open, but that could change in the future to become an issue.  If you will be keeping the oil system forever, the baseboards will prob keep everything nice and even.  Go with Company 3 (as quoted or upsize).

But if you hope to get rid of the oil, then the company 3 option might force elec baseboards or elec boiler options in the future, whereas having two heads upstairs might avoid that issue all together.  I might want a three head system, one big downstairs, one small in each upstairs bedroom, total nom BTU > 30 kBTU.

Think about your future plans, and talk to your installers some more.....

--At $0.18/kWr, your cost per BTU will be equivalent to ~$2.25/gallon oil (10% better than that in warm weather, worse in cold weather).  If you can buy oil at $3.50/gal discount, this whole shebang will only save you $1.25*550 gal = $700/year. (assuming higher usage from a 65° setpoint) 
--That is a ~9 year payback on the cheapest option, assuming oil and elec stay the same price.  If you get a elec discount for heating, this changes big in your favor.  If oil gets cheaper by 30% next year, you lose.
--Changing your DHW service over to elec or a HPWH could save you 150 gallons outright (if your boiler could get shutdown in the summer), saving you several hundred dollars a year net.  This might have a better payback than the minis, depending on the cost of plumber.


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## Dave A.

woodgeek said:


> PS: The folks pushing the '100% heating capacity at XX°F' are in my opinion selling snake oil. All HPs run on refrigerant, and the volatility (vapor pressure) of the refrigerant goes down with decreasing temp, so the BTU/h goes down too. This is not a design flaw for HPs, it is physical chemistry. The units that 'deliver 100%' down to some temp are just being throttled down above that temp. Duh. All you care about it that the BTUs delivered on an average Jan day meet your needs. All minis will throttle down above that (which is nice, since they will run quieter and more eff then). The Hyper Heat units are nice, and if I lived North of Boston climate-wise, I would research them. If you are in the lowlands in southern CT, with a roughly NYC climate, you don't need to go there.



Not sure where you're coming from here.  First they're snake oil, then they're good in colder climates.  No personal axe to grind with respect to the Hyperheats, don't even own one. But I do like the specs compared to other heat pumps.  Most heat pumps significantly drop their BTU heat output as the outside temps drop and the temp of the heated air drops as well.  Is that really what you want in a heating system.   Not sure what changes Mitsubishi makes with the Hyperheats that allows a more user friendly heat pump system than others but it does sound (to me) like the direction the industry should be going.

We can get 5F temps here in this climate and a heat pump that works without requiring backup to 5F sounds pretty good to me.  Electric backup has been the dirty little secret about heat pumps that's given them a bad name making people think they are inherently expensive to run. The resistance electric is automatically turned  on at almost every opportunity (unless you work it out with your installer to set up the system otherwise)  driving the utility costs up without the user even being aware of it.  It's turned on during defrost cycles, turned on whenever the thermostat is turned back up to more than a degree or so above the current inside temp and turned on below certain outside temps.  Although the heat pump may be still making minor contributions, most of the energy use is generated by the resistance heating at these times.

The hyperheat avoids all that, it's pure heat pump.  What's wrong with that.


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## woodgeek

I just don't like downtalking the capabilities of other systems in milder climates (I think that is overstated). 

No personal opinion about HyperHeats whatsoever. I just think that properly installed HPs of modern vintage are aok as far north as southern New England.  Beyond that, it seems a lot of folks are happy with the their HyperHeats.  I'm cool with that.  I just stop short of folks saying that its HyperHeat or no go, and describing bad installs or systems from 20 years ago.  I've got a cheapo 4-ton mid-range Goodman brand HP heating my house for $700/yr, and my climate is basically a match for NYC/southwestern CT.

I think HPs will revolutionize heating in New England, and are a possible solution for lots of folks stuck on Heating Oil.  The glass is full, there are many systems that will work in southern NE, and at least one (HyperHeat) that works well in the North.


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## Wear More Layers

Everyone has given me a lot to think about.  My head is going to explode.  My latest completely unorganized thoughts that I'm trying to tie together include:

-My goal is to save money to heat my house into the low 60s (though if the splits bring it to 68, I'll live).  Recouping $700/yr is lower than I had hoped, but I see that the ridiculously high elec rates in CT contribute to this reality.

-I don't have central air conditioning, and with a ductless home, estimates for installing traditional AC on both floors run from $7,500 up.  I was even looking at mini-splits in the dog days of summer last year but didn't bite.  (At that time I didn't know some of them provided both heat and cooling.)   Getting AC as part of the deal makes the $700/yr return on my investment more palatable.

-I don't know what the future holds but expect that if a bedroom down the road needs a door closed for extended periods, a small space heater could solve the problem if it got cold and the oil heat didn't kick on.

 -I don't plan to get rid of my oil boiler.  With a pricy hot water tank running from it plus a new oil tank, both installed within the past 5-6 years, I'm wedded to oil at least for DHW for the foreseeable future. 

In sum, knowing that it will be hard for me to go completely oil-free, I don't think it's worth spending over $9,000 on HPs at this time.  I will call Company 3 and double-check whether they think they've sized the units properly.  I'll also call Company 2 to see if they'll reconsider installing 1 bigger unit upstairs instead of 2 smaller ones.

As for regular HP vs. Hyper Heat, none of the 3 companies recommended Hyper Heat.  I don't know if it's because they didn't think it gets cold enough here or because they knew the cost would be too great.  Does anyone know the price difference between regular Mitsubishi's and Hyper Heat versions?


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## velvetfoot

woodgeek said:


> I think HPs will revolutionize heating in New England


Watch electric prices go up then, lol.


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## flyingcow

Wear More Layers- My hypers were $600 more than a regular HP. My utility company was offering a $600 rebate, just on the hypers. But, it may have changed since this summer. Wouldn't hurt to check. It cost me a just a shade over $4k for my downstairs 18kbtu unit. I have it running now, it's 15f outside temp. Purring like a kitten. The variable speed compressors and fans are whats making these units favorable to the northern climate.

FWIW, i have a gassification wood boiler. prettty damn efficient in it's own right. On the back of an envelope figuring, the HP is on par( if not cheaper) for heat. Once I get a meter hooked up to HP, i will be able to get real numbers for my cost. I'm using the HP for heat during the day and running the wood boiler for DHW and radiant floor in my kitchen. I'm using significantly less wood playing with my new toy. It's supposed to be zero or below zero later this week. Might play with the HP and see whats happens. But I'll pretty much be back into the wood boiler 24hrs a day at those temps.


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## Wear More Layers

flyingcow said:


> Wear More Layers- My hypers were $600 more than a regular HP. My utility company was offering a $600 rebate, just on the hypers. But, it may have changed since this summer. Wouldn't hurt to check. It cost me a just a shade over $4k for my downstairs 18kbtu unit. I have it running now, it's 15f outside temp. Purring like a kitten. The variable speed compressors and fans are whats making these units favorable to the northern climate.
> 
> FWIW, i have a gassification wood boiler. prettty damn efficient in it's own right. On the back of an envelope figuring, the HP is on par( if not cheaper) for heat. Once I get a meter hooked up to HP, i will be able to get real numbers for my cost. I'm using the HP for heat during the day and running the wood boiler for DHW and radiant floor in my kitchen. I'm using significantly less wood playing with my new toy. It's supposed to be zero or below zero later this week. Might play with the HP and see whats happens. But I'll pretty much be back into the wood boiler 24hrs a day at those temps.




Thanks flying cow.  I'll see what prices my local companies give for hyper heats.  How do you keep your outdoor unit free of snow up in Maine?


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## flyingcow

Wear More Layers said:


> Thanks flying cow.  I'll see what prices my local companies give for hyper heats.  How do you keep your outdoor unit free of snow up in Maine?




It's mounted on the wall of the house, up high enough not to bother. But we'll see, this is my first winter with it.


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## Wear More Layers

flyingcow said:


> It's mounted on the wall of the house, up high enough not to bother. But we'll see, this is my first winter with it.



None of the companies I talked to offered this solution.  After bigger storms I would have to go outside and shovel the snow from the unit, which would sit on a concrete pad at ground level.  Maybe I can convince them to elevate it atop pressure-treated lumber or concrete pavers to buy me at least a little extra clearance.


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## woodgeek

Wear More Layers said:


> None of the companies I talked to offered this solution.  After bigger storms I would have to go outside and shovel the snow from the unit, which would sit on a concrete pad at ground level.  Maybe I can convince them to elevate it atop pressure-treated lumber or concrete pavers to buy me at least a little extra clearance.



That is pretty unacceptable IMO.  I have my unit of 12" plastic legs called 'pump ups' and I seldom get more than 12" of snow.  Imagine going to bed with the blizzard coming....no fun.


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## Justin M

Wear More Layers said:


> How do you keep your outdoor unit free of snow up in Maine?


Mine is mounted on a metal stand on top of the pad that keeps it about 18" off the ground.


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## woodgeek

You could build (or pay a handyman to build) a couple 18" platforms out of pressure treated....I skipped the concrete pad, an just built a level frame of pressure treated, filled it with dirt and put a plastic pump pad on top.  That and the legs.


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## altmartion

did any of these contractors do a load calc? with mini splits it is crucial. they don't have the dehumidifying capacity as  a normal ducted system would. so it needs to be sized right.


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## flyingcow

Wear More Layers said:


> None of the companies I talked to offered this solution.  After bigger storms I would have to go outside and shovel the snow from the unit, which would sit on a concrete pad at ground level.  Maybe I can convince them to elevate it atop pressure-treated lumber or concrete pavers to buy me at least a little extra clearance.




Both units are on a wall hanger supplied my Mitsu. Pretty slick set up. Yrs ago i used ti install comm HVAC equipment. This bracket system is pretty slick. But There is a slight vibration coming thru from the outside wall. especially in the heat mode. I have my downstairs unit on outside wall. maybe 3ft up?  The upsatirs unit is about 18ft high. Both on the hangers supplied by Mitsu.

No pics, but this is one of the FAQ'a
http://www.mitsubishipro.com/en/professional/resources-and-tools/faqs


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## flyingcow

Not a great pic, not sure what will happen when you click on it


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## peakbagger

I built my own hanger out of spare unistrut and haven't noticed any extra noise on the interior. I also made a removable frame with a slant roof over the top of the heat pump that bolts to the hanger and the wall. The unit sits about 4' off the ground. Its near a driveway so I don't have room to plant a cedar in front of it. In addition to the mini split I have to have wall mounted disconnect and I also used the plastic gutter to route the control wire, condensate drain and refrigerant tubing.  I have cedar siding so everthing in contact with wood is either stainless or coated fasteners.


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## Justin M

Here is mine.


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## Dave A.

flyingcow said:


> But There is a slight vibration coming thru from the outside wall. especially in the heat mode.



Wondered about that.  Kind of going full circle -- get a mini split to get rid of the window shaker aspect of window/wall units, then hang the outside unit on the wall and end up back where you started.


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## flyingcow

Dave A. said:


> Wondered about that.  Kind of going full circle -- get a mini split to get rid of the window shaker aspect of window/wall units, then hang the outside unit on the wall and end up back where you started.


It's a pretty  minor vibra/noise. The house has to be dead quiet to hear it.


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## altmartion

flyingcow said:


> It's a pretty  minor vibra/noise. The house has to be dead quiet to hear it.


is it the unit itself or the refer line vibrating? it is common for the line to vibrate.


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## Wear More Layers

altmartion said:


> did any of these contractors do a load calc? with mini splits it is crucial. they don't have the dehumidifying capacity as  a normal ducted system would. so it needs to be sized right.



All 3 companies did load calculations, which is why I was surprised by their very different conclusions.  I called Company 3 back, and he indicated that he has installed thousands of units over the past decade and stands by his load calculations.  He mentioned that he sized the units for AC, and by doing so, it will be more than enough for heat.  Does that sound logical?


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## woodgeek

Not really.....your cooling loads are prob half of your heating loads.


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## Seasoned Oak

woodgeek said:


> Not really.....your cooling loads are prob half of your heating loads.


Ill say,My cooling cost are about $40 if that for the whole summer while heating costs are many many times that amount when heating with anything but wood. About $1000 minimum.My homes Cooling Capacity is 22000 BTUS while heating is 95000 BTUs.


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## Seasoned Oak

Wear More Layers said:


> All 3 companies did load calculations, which is why I was surprised by their very different conclusions.  I called Company 3 back, and he indicated that he has installed thousands of units over the past decade and stands by his load calculations.  He mentioned that he sized the units for AC, and by doing so, it will be more than enough for heat.  Does that sound logical?


Ill be sizing my minisplit for heat, which will be more than enough for cooling.


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## woodgeek

What Randy said.  ^^^

A NICE thing about minis is that their variable speed solves a problem.  In a single speed (on/off) HP, sizing it for heating makes it oversize for cooling, leading to comfort and dehumidification problems.  My singe speed system never runs more than 6 hours a day in AC, but can run flat out 24 hours in heating.  But my dehumidification is just 'ok'.  If it dried the air better, I could go a couple degrees warmer on the setpoint.  Oh well.  
A mini will throttle down for cooling and do a great, comfortable, quiet job of it.
Company 3 is starting sound like a loser.


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## Seasoned Oak

Hard to believe cooling load is greater than heating anywhere in the northern US.


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## flyingcow

altmartion said:


> is it the unit itself or the refer line vibrating? it is common for the line to vibrate.



outside unit. Not following the lines


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## altmartion

Wear More Layers said:


> All 3 companies did load calculations, which is why I was surprised by their very different conclusions.  I called Company 3 back, and he indicated that he has installed thousands of units over the past decade and stands by his load calculations.  He mentioned that he sized the units for AC, and by doing so, it will be more than enough for heat.  Does that sound logical?


somewhat.


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## Dave A.

When I was looking at heat pumps (not mini-splits) about two years ago. There were two types that seemed kind of appealing.  One was what's called a reverse cycle chiller, which produces hot water to run to an air handler coil, or for in floor radiant (refrigerant stays in the outside unit, only the water, hot or cold, is circulated).  Hot water temps were around 120F so not hot enough for baseboard heat.  But what was nice about this is that you had stored heat in the water, so during a defrost cycle (where you normally lose heating capability with the heat pump) you would still have the heat from the stored hot water.

The other was a system with a dual stage compressor.  And with one brand in particular you had a wide range of outputs for each compressor size. So like with a 36k BTU unit you could get as much as 72kBTU for heat out of it in the high stage or as low as 18k BTU for cooling in the low stage. This was nice because the problem with a lot of heat pumps in a mid-atlantic climate is if you size for heating you'll have too much cooling (and resulting poor dehumidification).


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## DBoon

You are getting a lot of good advice hear - nothing to add except that it is ok to go slow - just install one unit for now if you are worried about cost or want to see what the payback is like.  One 18kBTU unit downstairs will throw a lot of heat (more than 18kBTU when temperatures are above freezing) and be the least cost option.  You can always add more later if you want to.

Personally, I would get the Hyper Heat since I am an efficiency nut, but you'll still be plenty happy with the regular ones, especially if you are worried about the extra cost. 

I personally wouldn't put much faith in what the installer says about Hyper Heats...the installers I talked to were remarkably unawares of the specifics of their products.  I had to educate them and even specifically write down what I wanted them to quote me.  It was a big eye opener.  I would say that the quality of the advice you are getting here is likely better than what the installers are telling you.


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## altmartion

DBoon said:


> You are getting a lot of good advice hear - nothing to add except that it is ok to go slow - just install one unit for now if you are worried about cost or want to see what the payback is like.  One 18kBTU unit downstairs will throw a lot of heat (more than 18kBTU when temperatures are above freezing) and be the least cost option.  You can always add more later if you want to.
> 
> Personally, I would get the Hyper Heat since I am an efficiency nut, but you'll still be plenty happy with the regular ones, especially if you are worried about the extra cost.
> 
> I personally wouldn't put much faith in what the installer says about Hyper Heats...the installers I talked to were remarkably unawares of the specifics of their products.  I had to educate them and even specifically write down what I wanted them to quote me.  It was a big eye opener.  I would say that the quality of the advice you are getting here is likely better than what the installers are telling you.


you also give good advise. sometimes, more than it should be, installers only know how to install. that is strictly what they do. some of the bigger company's  around here won't let the install crew start the unit's. they are not trained like the techs or sales guy. if you want the real skinny on a product, talk to a good tech. they will most likely know more about it than the installer or salesman, and sometimes more than the manufacturer. lol. the tech can tell you reliability of a product and common issues.


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## woodgeek

DBoon said:


> You are getting a lot of good advice hear - nothing to add except that it is ok to go slow - just install one unit for now if you are worried about cost or want to see what the payback is like.  One 18kBTU unit downstairs will throw a lot of heat (more than 18kBTU when temperatures are above freezing) and be the least cost option.  You can always add more later if you want to.
> 
> Personally, I would get the Hyper Heat since I am an efficiency nut, but you'll still be plenty happy with the regular ones, especially if you are worried about the extra cost.
> 
> I personally wouldn't put much faith in what the installer says about Hyper Heats...the installers I talked to were remarkably unawares of the specifics of their products.  I had to educate them and even specifically write down what I wanted them to quote me.  It was a big eye opener.  I would say that the quality of the advice you are getting here is likely better than what the installers are telling you.



Agree about going slow....but if he puts it downstairs, he has no AC upstairs in the summer.


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## Floydian

Hello Wear More Layers,



Wear More Layers said:


> The company that suggested 2 units proposed: MXZ-2B20NA 2 port outdoor unit MSZ-GE12NA indoor unit, one on each floor The company that suggest 3 units proposed: MXZ4B36NA-1 outdoor unit MSZ-GE24NA indoor unit downstairs MSZ-GE09NA-8 in each upstairs bedroom.



I have to say, the specs on all the units you got quotes on are not all that impressive.

The MXZ-2B20NA is rated at 22,000 btus(heating) at 47 and only 12,500 btus at 17 and has an HSPF of 8.9 and a SEER of 18. Meh

The MXZ-4B36NA is rated at 35,400 btus(heating) at 47 and 22,000 btus at 17. I think  the HSPF is 9.3 and the SEER is 17.5 but I'm not sure as my Mitsu catalog is a little vague with this unit.

As mentioned the Hyper heat units do quite a bit better but require the 1:1 configuration, also as mentioned. I was set on the Mitsu Hyper Heat for my folks super insulated house because of the superior performance vs the regular units. Then I started looking at the Fujitsu's and I encourage you to do the same.

Fujistu has the xxRLS2H series which is the direct competitor of the Mitsu Hyper Heat units but I think a better fit for you would be the xxRLS2 series, particularly the 12RLS2 or the 15RLS2 for your downstairs. http://www.fujitsugeneral.com/wallmountedRLS2_specs.htm

Heating specs on these units:

The 12RLS2 is rated at 16,000 btus at 47 and 15,000 btus at 5 and has an HSPF of 12.12,000 btus cooling and SEER of 25

The 15RLS2 is rated at 18,000 btus at 47 and 17,000 btus at 5 with an HSPF of 12 also. 15,000 btus cooling and SEER of 21.5

This units are also likely to cost less than the comparable Hyper Heat units.

Check for Fujitsu dealers/installers in your area and maybe get a couple quotes for two separate units. One upstairs and one down.

IMO, this would give you more bang for your buck and get you more heating capacity when you really need it without a lot of up charge over the quotes you have already received.

Sorry if this adds to your headache,
Noah


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## Wear More Layers

Based on everyone's comments and Noah's very recent post, I'm both worried and confused.  

Worried because I invited Company 3 (two 12,000 Btus) back to talk me into a sale.  I'm not made of money, and their $6K figure was the lowest by far yet still a huge pill to swallow.  They also seemed to be the most experienced with installing mini splits. I will call them before they come over to press them on their statement that sizing the units for cooling will lead to more than enough capacity for heat.  

Confused because I truly don't know what size units I really need.  I'm definitely going to get a maximum of 2 units, but should it be 12/12, 18/9, 18/12, 18/18, 24/9……..?  Only Company 2 showed me their heat load calculations and came up with ~39,000 Btus.  Given 24,000 Btus from Company 3 and 36,000 from Company 1, I get an average of 33,000 Btus.

Nobody offered me Fujitsus as an option even though 2 of the companies are listed on the Fujitsu website as dealers (that's why I called them in the first place).

I guess in the end I really need to follow DBoon's advice and slow down.  After several months of researching pellet stoves, wood stoves, and now mini splits, I had hoped to have settled into winter with some warmth.  I guess I'll just have to Wear More Layers for a little while longer.

Don't let that stop you from continuing to offer advice!


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## Wear More Layers

One thing I just thought of:  The companies that recommended 36,000 Btus and 42,000 Btus used as their baseline an indoor temperature of 75 degrees.  I don't need nearly that much heat.  I think Company 3 (24,000 Btus) took me at my word that I'd be happy with temps in the low 60s.  Is it possible that 24,000 Btus in my house would lead to temps in 60s?

Interestingly, the company that showed me their calculations figured that the house needed 23,000 Btus for AC.  That's right where Company 3 sized the units for, which jives with their statement that they sized the house for cooling and that this size would be enough for my heating needs.

Just a thought.


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## Floydian

Wear More Layers,

Are you heating with hot water baseboard or cast iron radiators? If you  have CI radiators then heating to the low 60's with radiant is a LOT more comfortable than convection. MIni splits would require at least a few degrees warmer to achieve the same level of comfort as radiant but would be comparable with baseboard. Just curious.

As far as heating and cooling load calcs go, unless these guys or gals are taking lots of measurements all over your house(exterior ceilings, floors, walls, windows, doors, etc...) then they are just guessing.
Then they have to assign the right R-values or the numbers could be all over the place. And they will have to guess about the air exchange rate unless you have had a blower door test done.
A real heating/cooling load calculation is going to take a least a couple of hours and they will want to charge you to actually do this I would think. Sounds like heating/cooling load guesses to me and they might be close or they might not.

In truth this is something you could do yourself along with some help here IF we have the right numbers to plug in or else...garbage in, garbage out.

I don't think this is really needed though. Woodgeek's numbers with your prior oil usage look pretty sound to me and with mini splits it is safe to oversize up to about 1.5x. More than that and efficiency will start to drop as well as comfort. Undersized and  you have the oil boiler to back you up if the mini splits come up short.

My main point was that if you are spending the coin on the mini's why not get enough capacity to use as little oil as possible. It could be doable and who knows, maybe you add some grid tie PV in the future to help offset your electrical usage. Yeah, we love to spend your money for you. 

I know this stuff can be frustrating. Hang in there, a solution will present itself.

Noah


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## woodgeek

Let's start over.  You should def take a little time here.

*Install cost:*
If you bought a small minisplit, that provided X BTU/h and cost $Y installed and a bigger minisplit that also provided 2X BTU/h and cost 2Y, the smaller one will have a better payback because it would run all the time, while the bigger one might be idle sometimes (and thus not providing any value).  So, the goal is different than with a furnace. With a furnace, you want to exceed your maximum demand so you never get cold.  With a HP, the payback starts to suffer when the HP is oversized.

Frankly, I trust any demand calc based on usage more than any computer model done by a contractor.  If your 450 gallons/year at your stated low temp is accurate, my estimate of 26 kBTU @ 70°F inside and 28°F outside is prob accurate to better than ±10%.  The amount of oil you save annually is roughly proportional to the systems BTU/h output at 28°F for small units, but can't exceed 450 gallons no matter how large it is.  By my estimate, a system that puts out 26 kBTU/h at 28°F would offset >80% of your oil usage.  A single mini downstairs that puts out 18 kBTU might still cover 60-70% of your usage and cost half as much (and thus have better payback)

Since hot air rises, and the stack effect brings cold air from the bottom of the house I might skew the system to somewhat higher BTU/h downstairs.  Maybe 18/12.

*Operating cost:*
On my side, I found that to a decent approximation, your operating efficiency is well approximated by that at your average January temp.  You can look that up for your zipcode, but I would guess is is ~27-29°F.  If Noah can find COP data for different models at that temp, you can convert those to costs per million BTU.  Which unit puts out closer to nominal output at 5°F is irrelevant....you don't spend enough hours at 5°F for that to matter.

If your system offsets 350 gallons, it saves you $1200-1400 on oil. But at COP = 2.5 @ 28°F it would add $700 to your elec bill.  If Noah finds a unit that works at 15% higher COP, that saves you $100/year.  Compare that to the difference in install cost.  In my case the lowest cost of ownership over 10 years was one step below the most eff unit.

This is frustrating, if your elec cost were <$0.15/kWh, the payback would be <6 years and it would be a no brainer.  At 9 years payback, with some unpredictability in elec and oil prices, there is no rush to move.  Do some internet research on kWh pricing options and/or call your utility.  If you can get a lower rate, it will make the decision clearer.


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## Wear More Layers

Floydian said:


> Wear More Layers,
> 
> Are you heating with hot water baseboard or cast iron radiators? If you  have CI radiators then heating to the low 60's with radiant is a LOT more comfortable than convection. MIni splits would require at least a few degrees warmer to achieve the same level of comfort as radiant but would be comparable with baseboard. Just curious.
> 
> As far as heating and cooling load calcs go, unless these guys or gals are taking lots of measurements all over your house(exterior ceilings, floors, walls, windows, doors, etc...) then they are just guessing.
> A real heating/cooling load calculation is going to take a least a couple of hours
> 
> I don't think this is really needed though. Woodgeek's numbers with your prior oil usage look pretty sound to me and with mini splits it is safe to oversize up to about 1.5x. More than that and efficiency will start to drop as well as comfort. Undersized and  you have the oil boiler to back you up if the mini splits come up short.
> 
> Noah



Thanks Noah.   I do have cast iron radiators and didn't consider the difference with convection heat.  The last thing I want to do is feel even colder than I already do.   

t think you're right that everyone just guessed with their calculations because nobody took detailed measurements.  If I go by Woodgeek's numbers, then I should aim for 26,000 Btus at a minimum.  I've found the names of 3 more local companies that are listed on the Fujitsu site and will try reaching one or two tomorrow.


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## woodgeek

Wear More Layers said:


> If I go by Woodgeek's numbers, then I should aim for 26,000 Btus at a minimum.



Rather than 'at a minimum', you should think 'diminishing returns' for systems larger than 26 kBTU/h.


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## Wear More Layers

woodgeek said:


> Let's start over.  You should def take a little time here.
> 
> *Install cost:*
> If you bought a small minisplit, that provided X BTU/h and cost $Y installed and a bigger minisplit that also provided 2X BTU/h and cost 2Y, the smaller one will have a better payback because it would run all the time, while the bigger one might be idle sometimes (and thus not providing any value).  So, the goal is different than with a furnace. With a furnace, you want to exceed your maximum demand so you never get cold.  With a HP, the payback starts to suffer when the HP is oversized.
> 
> Frankly, I trust any demand calc based on usage more than any computer model done by a contractor.  If your 450 gallons/year at your stated low temp is accurate, my estimate of 26 kBTU @ 70°F inside and 28°F outside is prob accurate to better than ±10%.  The amount of oil you save annually is roughly proportional to the systems BTU/h output at 28°F for small units, but can't exceed 450 gallons no matter how large it is.  By my estimate, a system that puts out 26 kBTU/h at 28°F would offset >80% of your oil usage.  A single mini downstairs that puts out 18 kBTU might still cover 60-70% of your usage and cost half as much (and thus have better payback)
> 
> Since hot air rises, and the stack effect brings cold air from the bottom of the house I might skew the system to somewhat higher BTU/h downstairs.  Maybe 18/12.
> 
> *Operating cost:*
> On my side, I found that to a decent approximation, your operating efficiency is well approximated by that at your average January temp.  You can look that up for your zipcode, but I would guess is is ~27-29°F.  If Noah can find COP data for different models at that temp, you can convert those to costs per million BTU.  Which unit puts out closer to nominal output at 5°F is irrelevant....you don't spend enough hours at 5°F for that to matter.
> 
> If your system offsets 350 gallons, it saves you $1200-1400 on oil. But at COP = 2.5 @ 28°F it would add $700 to your elec bill.  If Noah finds a unit that works at 15% higher COP, that saves you $100/year.  Compare that to the difference in install cost.  In my case the lowest cost of ownership over 10 years was one step below the most eff unit.
> 
> This is frustrating, if your elec cost were <$0.15/kWh, the payback would be <6 years and it would be a no brainer.  At 9 years payback, with some unpredictability in elec and oil prices, there is no rush to move.  Do some internet research on kWh pricing options and/or call your utility.  If you can get a lower rate, it will make the decision clearer.




Thanks Woodgeek.  I've investigated elec rates and switched to the lowest cost provider in my area.  Unfortunately, the overall kWh prices have little to do with the cost of generating electricity.  Most of my bill is made up of distribution charges, fees, and taxes.  (And people wonder why companies are fleeing the state of CT.)

When I call companies tomorrow, I will tell them that I'm thinking of 18 downstairs and a 9 or 12 upstairs.


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## Wear More Layers

woodgeek said:


> Rather than 'at a minimum', you should think 'diminishing returns' for systems larger than 26 kBTU/h.



Good point.  You know, Company #3 told me that the 12,000 Btu units are capable of 15,000 Btus each as long as both aren't ramped up to full speed at the same time.  His point was that I'd be getting more than 24,000 Btus.  II think I read somewhere that each could generate 14,400 Btus.  So if 26 is the point of diminishing return, is Company 3 on target?

I gotta go to bed.  My brain hurts.


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## peakbagger

minus 13 degrees at my house and the minis split is still running and putting out some heat. It locks out at minus 15 but I am impressed. Obviously the COP is darn low but more than 1, but the power is free from my net metering on solar.


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## flyingcow

The gentleman that installed mine was telling me that his was about -19 before it quit. He uses it all winter. Pellets and oil for back up.


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## peakbagger

After a bitter cold day (less than 10 F I think, the main floor of the house got cold away from the heat pump. Its still putting out heat but I expect the heat loss exceeds the heat pump output. I also noticed some ice buildup from snow that drifted on the coils. I think I will make some more robust snow shields around it one of these days.


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## Wear More Layers

peakbagger said:


> minus 13 degrees at my house and the minis split is still running and putting out some heat. It locks out at minus 15 but I am impressed. Obviously the COP is darn low but more than 1, but the power is free from my net metering on solar.



What kind of mini split do you have?


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## Seasoned Oak

Why even try to push heat pumps at those temps. Is it not hard on the equipment to try to push heat pumps to make heat at sub-Zero temps? I would be firing up pellets or even oil at those temps.


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## peakbagger

Mitsubishi Hyper heat 1 ton..

With regards to "pushing" heat pumps, the unit is rated down to minus 15 and has a lockout when it hits that temperature and has a seven year guarantee on the compressor. I would expect that if there was a issue with using the equipment at low temps they would set the lock out at the point where this wasn't an issue. The reason for not running pellets or oil is that my power is essentially free based on a net metering surplus plus I don't have to feed pellets and scrape out a burn pot on occasion. I travel for work on occasion and would like an alternative to just running the house on oil at $3.40 per gallon.


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## Seasoned Oak

AS you said below -10 you dont have much choice.


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## Wear More Layers

I invited Company # 3 back to explain their calculations in person.  He still comes up with needing no more than 24,000 Btu and offers a 1 year satisfaction guarantee on meeting my heating needs.  Also, if I fear that I'm really not going to have enough heating capacity, I could upgrade from the original proposal to a slight larger set-up:
 original -- 2 port external unit at 20,000 Btu; two 12,000 Btu indoor units = $6,300
 alternative -- 3 port external unit at 24,000 Btu; one 15,000 Btu downstairs unit and one 12,000 Btu unit upstairs = $7,200

I also had a 4th company come out to give me estimates on Fujitsu units and am waiting on their proposal.

It appears that the $300 federal tax credit will go away on 12/31, so it looks as if I've lost out on some savings.


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## Floydian

Hi again Wear More Layers,

I've been meaning to comment on your situation. I'm concerned about your comfort level switching from CI rads to point source with warm air. I really think you will need to keep your air temp at least 4 or 5  warmer to achieve the same comfort you are used to now. Maybe not during mild temps but when it drops into the 20's during the day and colder at night you are going to feel the difference if you  heat your house to 62. CI radiators offer a higher degree of comfort  because they heat both the objects in your house as well as the air. MSHP's heat the air and you just don't get much heat transfer between warm air and cool objects.

That said I still think a MSHP could be a good fit for your situation, I just don't feel the MXZ-2B20NA is it. Again, it puts out 22,000 btu/h at 47 and 12,500 btu/h at 17. It would be nice to know the output at temps in between but I can't find that info. If we take a guess based on drop in output from 47 to 17, you could be looking at 18,900 btu/h at 37 and 15,600 btu/h at 27.
That is well short of the woodgeek's number of 26,300 btu/h at 28 and maybe worse still if you really do need 4 or 5 more degrees vs the CI rads.

As you may be forced to rely on oil in the colder temps regardless of what options you choose, I think I would be looking at a single unit installed in the lower level of the house to take a big bite out of the oil bill. Natural convection should allow enough warmth to make it upstairs assuming doors are open most of the time. With Mitsubishi, the MSZ-GE24NA  would still give you more btu's at 27 vs the MXZ-2B20NA and it should cost less too. With Fujitsu the 15RLS2 could be a good fit at 18,000 btus all the way down to 5.
I would hope you could get either of the these units installed for under $5K, maybe even closer to 4k?

Obviously a unit like this installed downstairs does nothing to AC upstairs but a few hundred bucks on a window AC unit could solve that issue for not much money.

It's too bad that air to water heat pumps are not further along at this point. They are out there but prohibitively expensive. I look for this to change in the not so distant future.

Not sure I am really helping you in any way, sorry.

Noah


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## peakbagger

I agree with Flyodians observation. I normally keep my house at 66 when I am running baseboards,  with the heat pump I tend to run a few degrees warmer. I have baseboard but not a lot of it as the house is well insulated so I don't have any real radiant . I don't know about 4 or 5 degrees but I ascribe some of it to the draft from the blower which is far more noticeable than the minor convective draft from baseboard. In general I think the heat pump tends to stratify the air more, its noticeably warmer near the ceiling and the difference between the ceiling and floor is noticeable. I also have learned not to set my heat pump back at night like I do baseboard. 

Its all a learning curve. All I know is that the zone for my main floor is set at 58 degrees and generally above 10 degrees outside the main  floor stays at 65 so the heat pump is contributing.


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## Seasoned Oak

peakbagger said:


> Mitsubishi Hyper heat 1 ton..
> With regards to "pushing" heat pumps, the unit is rated down to minus 15 and has a lockout when it hits that temperature and has a seven year guarantee on the compressor. I would expect that if there was a issue with using the equipment at low temps they would set the lock out at the point where this wasn't an issue. The reason for not running pellets or oil is that my power is essentially free based on a net metering surplus plus I don't have to feed pellets and scrape out a burn pot on occasion. I travel for work on occasion and would like an alternative to just running the house on oil at $3.40 per gallon.


WoW thats what i call a backup plan and a back up for the back up. Only weak link i can find here is a power outage,but im sure your prepared for that as well.


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## Former Farmer

Wear More Layers said:


> I invited Company # 3 back to explain their calculations in person. He still comes up with needing no more than 24,000 Btu and offers a 1 year satisfaction guarantee on meeting my heating needs.



What temperature is he guaranteeing?  If this does not meet your heating needs, what will he do?  Will he install another system to meet your needs, all at his expense?


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## peakbagger

Backup plan if I am not home and the power goes out is homeowners insurance


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## Wear More Layers

Former Farmer said:


> What temperature is he guaranteeing?  If this does not meet your heating needs, what will he do?  Will he install another system to meet your needs, all at his expense?



He didn't mention what temp he'd guarantee. I'll have to ask. He did say that if the units don't keep the house at a desired temp, they company would install larger units.


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## Wear More Layers

Floydian said:


> Hi again Wear More Layers,
> With Mitsubishi, the MSZ-GE24NA  would still give you more btu's at 27 vs the MXZ-2B20NA and it should cost less too. With Fujitsu the 15RLS2 could be a good fit at 18,000 btus all the way down to 5.
> I would hope you could get either of the these units installed for under $5K, maybe even closer to 4k?



Isn't MSZ-GE24NA an indoor unit and the MXZ-2B20NA an outdoor unit?

On Monday I'll be getting quotes from the company that sells Fujitsu units.  I'll see what solution he comes up with.


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## Floydian

Wear More Layers said:


> Isn't MSZ-GE24NA an indoor unit and the MXZ-2B20NA an outdoor unit?



Yeah, sorry about that. The outdoor unit for that is the MUZ-GE24NA.

I gotta run now but I'll post a little info on the Fujitsu's tomorrow.

Noah


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## Wear More Layers

I did some more reading on Mitsubishi and Fujitsu units.  Here's what I picked up in tonight's leisure reading:

-- It appears that to get the highest HSPF, I have to purchase single port outdoor units.  If I want a unit that has multiple ports, HSPF drops for Mitsubishi to 10.0 and Fujitsu to 9.8. 

-- Both brands are comparable in price for multiport units, with Fujitsu just a little cheaper.

--Whereas a company would charge $6,800 for a 2 port unit plus 2 indoor units, the same items online cost about $2,900 with tax and shipping.  Assuming additional materials plus labor adds $1,000 - $1,500 to the overall price, there's still another $2,400 - $2,900 in the mark-up.  Purchasing these things online voids the warranty, but is the warranty really worth $2,900?  Given how many websites are selling these things, people must find the savings to be worth the loss of warranty.   

Could purchasing these heat pump thingies get any more complicated?  Maybe I should just move south.


----------



## Seasoned Oak

THese companies should first have to determine if improper installation was the cause of failure before they can blanket void  warranties. I think its just a money grab to just "assume " their product failed cuz it was installed wrong.


----------



## flyingcow

they won't cover the warranty unless put in by an authorized installer.


----------



## DBoon

Hi Wear More Layers, 

You are seriously agonizing (likely without much benefit) about this.  

Either the Mitsubishi HyperHeat or Fujitsu RLS2H High Heat models are what you want.  You'll see them on-line for about half of what an installer will charge you.  If the installer is charging you more than 2x the on-line price, you are being ripped off.  Some will sell a 2x premium is a rip-off, but that is likely the lowest you will negotiate with a capable installer.  

The Mitsubishi literature and documentation is terrible, and the Fujitsu is somewhat understandable, but both will tell you that the BTU ratings are for pretty low temperatures (i.e. 5 degrees F) and that you get much more heat from them at temperatures above that.  Fujitsu and Mitsubishi rate their units differently, so don't go by model number alone.   You might have to dig out the installers manuals to find this info, but I've already looked at both and these are comparable units.  

Don't go with the multi-zone units.  They are not as efficient and comparisons get complicated and prices get expensive with anything but the high-wall indoor unit.  

Start slow with one single-zone unit downstairs.  You will likely want a Mitsubishi 18k BTU unit or a Fujitsu 15RLS2.   Sure, you won't have AC upstairs.  Put in window unit for the 2 to 3 weeks a year you need AC up there.  Then see how it works.  You can always add one more mini-split upstairs later. 

The first unit for ~$3500 will give you the biggest payback.  Start with that first and see if you want another (upstairs) later.


----------



## peakbagger

One thing I learned is that installing a slanted roof over the unit for winter is a requirement. I had made a temporary 45 degree angle snow roof to keep snow off the coils on the back of the unit which ahs worked well but the overhang was too short on the front of the unit and therefore water dripped done the front of the unit and froze on the plastic grill on the front of the unit during the icing event that is occurring locally. I expect once I mod the roof to have more overhang it will be far less of an issue.

I and service techs I have talked to all recommend the single units and not the dual head units, due to the major efficiency difference and need for heat in cold weather. The rebate program I bought mine under was $900 rebate for a$1,600 unit, so it was definitely worth it for me. My theory stated previously is that based on what techs have told me, they rarely if ever see a unit fail except due to poor installation or external influences like physical damage to the unit. They rarely if ever fix the units, the just swap out the damaged unit. The outdoor unit which has most of the wear parts and most likely to get damaged can be bought  separately so it highly unlikely you will have to buy the entire unit. Given the markup by installing dealers, I could buy an entire spare unit for less than their installed cost. Realistically, DIY is not real difficult, although it makes sense to hire a pro to do the lines if you dont have the specialized tools and the confidence. In theory the 7 year compressor guarantee is valid if you have a pro install, but the reality is that Mitsubishi has no system in place except its dealer network to make these repairs and it will be difficult to find a dealer that will honor a guarantee on a unit they did not install. I would expect they have some sort of cost split between Mitsubishi and the dealer on these repairs. The internet retailers can afford to sell them cheap as they have no need to have service network to honor guarantees beyond replacing a unit that was dead from the beginning.


----------



## woodgeek

What DBoon said!!  Really.

If you wanted to ditch oil, you would need an expensive system to cover your full heating needs and would need to worry about distribution to bedrooms and all that.

But you are keeping the oil, and just looking to take a big bite out of the oil man's bill.  One big mini downstairs will do that. Maximum ROI. You will have all the AC you ever need downstairs, and if a bedroom needs a small window unit, no bigs.  Its not like trying to AC a whole house with giant window units or an army of smaller ones. 

I also second the 2X mark-up.  If you're in a HCOL area, 2x equipment price is pretty much the bottom line for someone doing it for a living.  If you want to save money, you could do a lot of the install DIY, but it sounds like that is not your bag.


----------



## Wear More Layers

I think I get the financial logic of installing just 1 unit and making sure it's an efficient one.  I'm trying to figure out how it would work practically.  If I install 1 unit downstairs to heat that floor to a comfortable temperature, wouldn't that prevent the house thermostat (also downstairs) from kicking on?  Without the boiler turning on, I'd get no heat upstairs save for what limited amount rose naturally from the first floor.  I'd have to turn the thermostat up pretty high to get sufficient heat upstairs, which seems counterproductive.  

Given how much more time I spend upstairs (office, bed, bath, workout space) than down, does it make sense to buy only 1 unit but have it installed upstairs?

Thanks for continuing to provide advice.


----------



## woodgeek

I think we are assuming that warm air rises, so the upstairs would not freeze.  Might run a couple degrees cooler than downstairs, not a huge worry.

Even IF it was a problem, you would have multiple simple options....
1. You can stuff towels or foam pipe insulation in 50% of your downstairs hydronic baseboards (or close their flappers) to reduce their output, sending more heat upstairs. You might have two loops even in a one zone system, and can turn off the lower story loop by closing a valve??
2. You could move the thermostat upstairs, and get effectively 2 zones...the mini one downstairs and the stat/oil one upstairs (running much lower output due to warm air rising).
3. You could set up a fan for circulation, either box type on a landing or a ceiling fan in the stairwell.
4. some combination of these.


----------



## DBoon

Hi Wear More Layers,

You are going to find that the heat travels upstairs pretty well if the heat source is located downstairs.  I would just make sure that your minimize the heat loss upstairs as part of your install, so make sure you windows are well-sealed upstairs, and that you have good attic insulation so as to keep the upstairs temperature more constant.  You will find that you need to keep the downstairs five degrees warmer or so to keep the upstairs at a comfortable temperature.  The advice above is depending on the room layout, of course...

It is slightly problematic to have your thermostat for the oil furnace on the first floor.  Is there a way to move it to the upstairs?  Alternatively, you could look at zoning the furnace distribution, but that is probably more expensive than just moving the thermostat.


----------



## flyingcow

You only have 1 zone? Not a t-stat upstairs?


----------



## Wear More Layers

I have only 1 zone, with the thermostat in the one room which all of the companies targeted for the downstairs unit.  I don't think there's a straightforward way to move the thermostat upstairs.  

There's only 1 loop running through the house to all of the radiators.  None of the radiators has a shut-off valve that I can discern.  I'd be reluctant to gum up the radiators with foam insulation. Fans may be my one way of redirecting the heat upstairs.  

I think I need to step away for a little while.  Maybe taking a break will help regain some perspective.


----------



## Dave A.

Wireless thermostat could be placed in a different location than the wall stat and take temp readings from the remote location and transmit to the wall stat (avoiding rewiring stat to other location) and that location can be moved around.

http://www.smarthome.com/30403A/Venstar-Wireless-Thermostat-System-No-Need-to-Rewire/p.aspx


----------



## woodgeek

Wear More Layers said:


> I'd be reluctant to gum up the radiators with foam insulation. Fans may be my one way of redirecting the heat upstairs.



Sorry, I thought you had baseboards that are easy to close off or (reversibly) stop up with foam.   Then I saw you had cast iron.

My hydronic system was a single zone and a single pump hooked up to two loops (each with a sep shutoff valve), you'd never know without tracing the plumbing.  Have you done that?  Maybe you used to be gravity fed steam?

Moving the stat, if you don't want to just use Dave's wireless idea is not that bad.  You just need to snake a new low voltage cable....they're thin and you can take a circuitous route...follow the plumbing vent up from the basement to the attic, then drop it down from the attic where you want it, etc.   A handyman could to do it for you in <1 hour probably.


----------



## DBoon

Hi Wear More Layers, 

Having a single-zone cast iron radiant system definitely complicates things a little bit.  I had a single zone system with home run lines (direct lines) to each radiator.  The home runs all began in one of two pipes, and I split the system there.  In the process, the big old pump was replaced by two smaller Taco pumps and I am likely saving about 50 to 60 kWh per month in the heating system (I saw my bills go down immediately).  Cost was about $1200.  Well worth it. Now, the bedrooms and bathroom (which are farthest away from the woodstove) are on a separate zone.  This makes the wife happy. 

FYI, the Fujitsu mini-split I speak of was put in a different house that I am just starting to renovate....

But even before I zoned my cast iron heating system, I still got a lot of benefit from the woodstove.  Now I am just getting more.  Your setup is a little different - heat does rise pretty remarkably well.  I would still go forward with a mini-split, but now I would mostly definitely just start with one downstairs and run it as much as you can and see how the heat flow works.  It is quite likely that 50% of the time the mini-split will take the full heat load for you (like in Spring and Fall) which is when they are most efficient and the heat loss in the upstairs will not be as great.  Then, you would just run your oil boiler in the deep winter (and you could still run your mini-split in the winter overnights or at some baseload temperature to moderate the need for the boiler).  

I say "go for it" - get the one downstairs to start.  Once you do, you are going to wonder why it took you so long to get it.


----------



## woodgeek

If you have an open stairwell to the upstairs, you will be fine with heat rising.  If the indoor head is close to the stairs you might get more heat upstairs than down (I am not recommending you put it that close, just saying).  Warm air pools on the lower level ceiling, and flows horizontally until it reaches the stairwell and pours up the stairs.  Cool air from upstairs returns at tread level.

If we were talking wood or pellet stoves....we would want to see a floorplan.  You did say your downstairs was open plan...


----------



## peakbagger

For what its worth, I am heating half my second floor with a one ton unit located on the first floor. The heat runs up an enclosed stairwell in the center of the house. I have to run my heat pump at around 69 degrees to maintain 65 in the office. Its good down to about 20 degrees but takes a long time to warm up if I close the doors. I have 12" of insulation between the main floor and the second floor. I also run a ceiling fan running upwards in the second floor office as the heat tends to stratify near the ceiling.


----------



## velvetfoot

This thread all sounds similar to my setup, only I have a thermostat upstairs.  A/C would be nice for less than 10 days a year and so far we've been heating mostly with wood:  the insert is kind of acting like the heat pump, and oil (and/or electric space heaters) heating the upstairs.

Has anyone heard anything good about the Toshiba/Carrier units?  I might be able to get a deal on the equipment.


----------



## Wear More Layers

Happy New Year.  Thank you for all of the advice you offered me last year.  I took a break and am now trying to finalize my heating plan as one of my goals for 2014.  Based on your combined wisdom, the suggested most cost-effective plan is:
1. buy 1 downstairs unit
2. move the thermostat upstairs (= $170 for a wireless unit)
3. buy a room air conditioner for upstairs (= $300 for a 12,000 BTU window unit)

I've looked into single mini split units and came up with the table of choices below.  I hope the table format is legible.  I did not include the Mitsubishi Hyperheat because the indoor unit is too long to fit on my wall.

BrandUnitBTU/47FHSPF/47FCOP/47FBTU/17FCOP/17FcoolingSEERCost
Fujitsu15RLS218,000120.99??14,50021.5$1,757
Fujitsu15RLS2H18,00010.33.91??14,50021.5$1,910
MitsubishiMSZ-GE18NA21,600103.3313,4002.7117,20019.2$2,021
MitsubishiMSZ-GE24NA27,600103.4616,0002.6422,50019$2,260


Notes: 
- Mitsubishi lists data for 47 F and 17 F. I couldn't find comparable 17 F data for Fujitsu.
- I calculated COP by hand for several units when I couldn't find published data and was surprised by the 15RLS2 COP of 0.99.  
- Costs are for online purchase only.  I'm assuming that installation costs will be the same independent of brand or unit.

My questions:
- Given all of the above info, what are the most important factors I should be considering?  Total heat output?  HSPF?  COP?
- Does a lower COP mean higher operating costs?  Connecticut (and NY) boasts the highest elec rates in the continental US, so I need to keep an eye on the cost to run the unit.


----------



## Wear More Layers

Wear More Layers said:


> Happy New Year.  Thank you for all of the advice you offered me last year.  I took a break and am now trying to finalize my
> 
> BrandUnitBTU/47FHSPF/47FCOP/47FBTU/17FCOP/17FcoolingSEERCost
> Fujitsu15RLS218,000120.99??14,50021.5$1,757
> Fujitsu15RLS2H18,00010.33.91??14,50021.5$1,910
> MitsubishiMSZ-GE18NA21,600103.3313,4002.7117,20019.2$2,021
> MitsubishiMSZ-GE24NA27,600103.4616,0002.6422,50019$2,260
> /quote]
> 
> I see that the table format got all screwed up. Sorry about that.  Here's another attempt:
> 
> Brand           Unit                 BTU/47F HSPF/47F     COP/47F     BTU/17F      COP/17F      cooling       SEER         Cost
> Fujitsu         15RLS2            18,000     12                   0.99                ?            ?                   14,500             21.5         $1,757
> Fujitsu         15RLS2H         18,000     10.3                3.91               ?              ?                  14,500             21.5        $1,910
> Mitsubishi    MSZ-GE18NA  21,600   10                   3.33           13,400      2.71              17,200             19.2         $2,021
> Mitsubishi   MSZ-GE24NA   27,600  1 0                  3.46            16,000     2.64                22,500              19           $2,260


----------



## Wear More Layers

Well that's annoying.  If you have a suggestion for how to show a table of data, please let me know.  Copying an excel table didn't work. Manually spacing columns of data didn't work, either.


----------



## Seasoned Oak

Its easy to minimize heat coming from cast iron radiators. Each one has a valve you can adjust in a feed and return system. In a loop type system just put an old blanket one the ones you DONT want heat from.  If its baseboard cast iron , block the air vents.


----------



## Floydian

Happy New Year!

This is the info you want for the Fujitsu 15RLS2: http://m.master.ca/documents/4Fujitsu_Technical_Manual_9_12_15RLS2.pdf

Page 8 has the basic specs and page 15 has a table with more in depth specs on total capacity and input power at given outdoor temps. Even at -5 you should still see a COP of 2+.

This is also an interesting bit of info: http://www.nrel.gov/docs/fy11osti/52175.pdf  . Basically shows that real world performance and manufacturer ratings are pretty close.

Noah


----------



## Wear More Layers

Floydian said:


> Happy New Year!
> 
> This is the info you want for the Fujitsu 15RLS2: http://m.master.ca/documents/4Fujitsu_Technical_Manual_9_12_15RLS2.pdf
> 
> Page 8 has the basic specs and page 15 has a table with more in depth specs on total capacity and input power at given outdoor temps. Even at -5 you should still see a COP of 2+.



Thanks very much, Noah.  The 15RLS2 looks like a good performer, and it's the least expensive model ($1,760) I've seen for its size.  One question: If you know, what's the difference between this one and the 15RLS2H?  The latter is more expensive yet has a lower HSPF and identical COP, SEER.

So do people think an 18,000 BTU (at 47F) downstairs unit sounds reasonable?  Fujitsu doesn't go bigger, so the alternatives are Mitsubishi MSZ-GE18NA ($2,000, HSPF=10, COP=3.33) or 24NA ($2,260, HSPF=10, COP=3.46).


----------



## Wear More Layers

Seasoned Oak said:


> Its easy to minimize heat coming from cast iron radiators. Each one has a valve you can adjust in a feed and return system. In a loop type system just put an old blanket one the ones you DONT want heat from.  If its baseboard cast iron , block the air vents.



I can't seem to locate any valves for closing individual radiators.  Once the cold snap breaks I can try wrapping a radiator in a blanket to see what happens.  It's safe to do this?


----------



## semipro

Wear More Layers said:


> Well that's annoying.  If you have a suggestion for how to show a table of data, please let me know.  Copying an excel table didn't work. Manually spacing columns of data didn't work, either.


Include it as a graphic (image) rather than tabular text.  
Excel allows copying as a "picture" directly.


----------



## Floydian

Wear More Layers said:


> If you know, what's the difference between this one and the 15RLS2H? The latter is more expensive yet has a lower HSPF and identical COP, SEER.



The 15RLS2H is Fujitsu's equivalent to the Hyper Heat from Mitsubishi. It provides heat down to -15 and has a heated base. I am not sure why the HSPF is lower but it my be rated for a colder climate than the 15RLS2 series. That is all I can think of but I have not looked into the H models much.

I think the 15RLS2 is a good fit for what you want to accomplish. 

A couple of things to keep in mind: 1.Fujitsu does not warranty online sales, period. 2. Local installers are likely paying more for the units than they are selling for online because the online units are not going through regional distributors. 

Noah


----------



## Seasoned Oak

Wear More Layers said:


> I can't seem to locate any valves for closing individual radiators.  Once the cold snap breaks I can try wrapping a radiator in a blanket to see what happens.  It's safe to do this?


Theres no safety issue. You are simply blocking the airflow over the cast iron surface.


----------



## woodgeek

Yeah.  With an electric radiator, it wold get a lot hotter if you blocked it. A hydronic radiator will just rise to the temp of the water and no further.

For a cosmetic solution, you could have those wooden/lattice 'radiator covers' made by a local outfit for not too much money, and put a little insulation under them to knock down their output by the desired amount.


----------



## Wear More Layers

semipro said:


> Include it as a graphic (image) rather than tabular text.
> Excel allows copying as a "picture" directly.



Just trying an experiment with coding the table in HTML.  Ignore this post if it looks like a mess.



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<tr height=15 style='height:15.0pt'>
  <td height=15 class=xl89 style='height:15.0pt;border-top:none'>Fujitsu</td>
  <td class=xl79 style='border-top:none;border-left:none'>15RLS2H</td>
  <td class=xl90 style='border-top:none;border-left:none'>18,000</td>
  <td class=xl79 style='border-top:none;border-left:none'>10.3</td>
  <td class=xl91 style='border-top:none;border-left:none'>3.91</td>
  <td class=xl79 style='border-top:none;border-left:none'>?</td>
  <td class=xl91 style='border-top:none;border-left:none'>?</td>
  <td class=xl80 style='border-top:none;border-left:none'>14,500</td>
  <td class=xl91 style='border-top:none;border-left:none'>21.5</td>
  <td class=xl81 style='border-top:none;border-left:none'>$1,910</td>
</tr>
<tr height=15 style='height:15.0pt'>
  <td height=15 class=xl89 style='height:15.0pt;border-top:none'>Mitsubishi</td>
  <td class=xl79 style='border-top:none;border-left:none'>MSZ-GE18NA</td>
  <td class=xl90 style='border-top:none;border-left:none'>21,600</td>
  <td class=xl79 style='border-top:none;border-left:none'>10</td>
  <td class=xl91 style='border-top:none;border-left:none'>3.33</td>
  <td class=xl80 style='border-top:none;border-left:none'>13,400</td>
  <td class=xl91 style='border-top:none;border-left:none'>2.71</td>
  <td class=xl80 style='border-top:none;border-left:none'>17,200</td>
  <td class=xl91 style='border-top:none;border-left:none'>19.2</td>
  <td class=xl81 style='border-top:none;border-left:none'>$2,021</td>
</tr>
<tr height=15 style='height:15.0pt'>
  <td height=15 class=xl89 style='height:15.0pt;border-top:none'>Mitsubishi</td>
  <td class=xl79 style='border-top:none;border-left:none'>MSZ-GE24NA</td>
  <td class=xl90 style='border-top:none;border-left:none'>27,600</td>
  <td class=xl79 style='border-top:none;border-left:none'>10</td>
  <td class=xl91 style='border-top:none;border-left:none'>3.46</td>
  <td class=xl80 style='border-top:none;border-left:none'>16,000</td>
  <td class=xl91 style='border-top:none;border-left:none'>2.64</td>
  <td class=xl80 style='border-top:none;border-left:none'>22,500</td>
  <td class=xl91 style='border-top:none;border-left:none'>19</td>
  <td class=xl81 style='border-top:none;border-left:none'>$2,260</td>
</tr>
</table>

</body>

</html>


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## Wear More Layers

Well that was a failure. Attached is a jpeg of the table.


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## Wear More Layers

woodgeek said:


> Yeah.  With an electric radiator, it wold get a lot hotter if you blocked it. A hydronic radiator will just rise to the temp of the water and no further.
> 
> For a cosmetic solution, you could have those wooden/lattice 'radiator covers' made by a local outfit for not too much money, and put a little insulation under them to knock down their output by the desired amount.



I looked up what kind of radiators I have and found that they're called "heating convectors."  It isn't feasible to wrap the metal fins in a blanket. At best I could cut foam insulation board to sit on top of the fins and duct tape the same to the underside.


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## Wear More Layers

Floydian said:


> A couple of things to keep in mind: 1.Fujitsu does not warranty online sales, period. 2. Local installers are likely paying more for the units than they are selling for online because the online units are not going through regional distributors.
> 
> Noah



Assuming Mitsubishi does honor warranties for online purchases, the closest in size is the MSZ-GE18NA.   I'd get 3,600 more BTUs (at 47F) than with the Fujitsu, but also a drop in HSPF from 12 to 10 and COP from 3.91 to 3.33.  The Mitsubishi is $250 more.  So which one pays for itself faster?  The one that offsets slightly more of my oil heat or the one that is more efficient?


----------



## woodgeek

With my elec rate, I would go for the more BTUs, with your elec rate, I would go with the higher *COP*.  The financial 'risk' on payback is that oil price drops 30% (small chance could happen) and then you don't run the mini.

On the radiators, pics of yours or similar on 'net?


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## Wear More Layers

woodgeek said:


> With my elec rate, I would go for the more BTUs, with your elec rate, I would go with the higher *COP*.  The financial 'risk' on payback is that oil price drops 30% (small chance could happen) and then you don't run the mini.
> 
> On the radiators, pics of yours or similar on 'net?



See http://inspectapedia.com/heat/Heat_Convector173-DFes.jpg for an image of the metal fins around copper pipes.  The exterior looks like http://inspectapedia.com/heat/Heat_Convector126-DFs.jpg .


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## woodgeek

If you wanted a permanent solution, and there were really no valves, I was suggesting having something like this made:





to go over, and put some foam between the radiator and the cover, perhaps with a small cutout.

Edit: sorry I am stupid.  You can just wrap the fin assembly (as in your first picture) with alum foil and then put the cover back on.  Wrap half the length, cut BTU output by 50%, 3/4s, cut it by 75%, etc.  Cheap and easy.  If it gets too cold, take some foil off.


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## Seasoned Oak

Wear More Layers said:


> I looked up what kind of radiators I have and found that they're called "heating convectors."  It isn't feasible to wrap the metal fins in a blanket. At best I could cut foam insulation board to sit on top of the fins and duct tape the same to the underside.


Just laying a cloth on top the fins would accomplish a great deal. You would stop 90% of the heat xfer. No need to "wrap" it with anything. It s the air flowing thru the fins you are trying to stop. THere is no need to insulate.


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## Dave A.

Note: There is a preview function before you post messages (select other options, then preview).  This allows you to see e.g. if your photos are upside down or not, or how any graphics will display in the final message.




Seasoned Oak said:


> Theres no safety issue. You are simply blocking the airflow over the cast iron surface. Randy



Exactly, you're preventing the radiator from cooling off and having to make the boiler run more to compensate for the heat given off.  The hot water then just flows into the next room without giving up any heat in the room where it was covered.


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## Dave A.

Not saying you're wrong but looking at the photo of the convector cover, that type usually will have shut off controls for each room with a pipe below the floor running into the next room.  I would double check particularly if you can see in the basement how they run -- if there isn't a pipe running below the floor into the next room (in fact, the shut off's might even be down in the basement, though they are typically under the convector cover in the room).

If not then all you want to do to prevent the heat transfer to the room is to put something above or below the fins (or both--though on top is easiest)  preventing air flow from rising through the fins.


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## Wear More Layers

I'm feeling kinda dumb because I can't find any shut-off valves. I have bleeder valves to get air out of an individual unit, but that's it.  I think each radiator runs a complete loop from the basement because when I get air in a  line and that room goes cold, the other rooms still get heat.  I have a total of 9 radiators, with 20 pipes feeding off the main loop in the basement, again leading me to believe that each radiator has its own circuit.  (Why there are 20 pipes and not 18 is a mystery.  I'm missing something somewhere.)

Anyway, aluminum foil, a rag, or foam board should decrease heat to a room.


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## Dave A.

If you actually do have separate lines to each convector then it should be relatively easy to install a valve in one (or more) of them to shut it off -- to more elegantly control it than by placing a barrier over the fins.  And those valves can be thermostatic (more costly of course than non-thermostatic valves) but allowing a room to have it's own thermostat.

Putting one thermostatic control valve in one convector would be relatively simple (not really effecting the rest of the system the way a zone valve system would usually be).

But if you do actually have a home run system like that, I would be surprised if there isn't already some means of disabling a separate run to a room, though there might only be balancing type valves (control it with a slotted screwdriver--vertical position is off, parallel to pipe run position is full on)


----------



## DBoon

Wear More Layers said:


> One question: If you know, what's the difference between this one and the 15RLS2H? The latter is more expensive yet has a lower HSPF and identical COP, SEER.



Hi Wear More Layers, 

The RLS2H is the lower temperature (equivalent to Mitsubishi Hyper-heat) unit.  I did all of the COP research myself, and though I can't find the documents now on my computer, the links Floydian sent seem very familiar.  You should be able to find a similar document for the RLS2H detailing the COP.  From memory, the COP of the RLS2 and RLS2H are the same to a certain temperature and then the COP of the RLS2H is better at lower temperatures.  Basically, with the RLS2H you get better (and actual useful) performance below 5 degrees F. 

In regards to why the HSPF of the RLS2H is worse than the RLS2, I asked the installer this same question.  He had no idea.  When researching HSPF, I came to the conclusion that the lower temperature units are penalized somehow since they operate over a broader temperature range, and naturally have a lower COP at lower temperatures since they still operate at those lower temperatures.  So I ignored the HSPF as a pretty "useless" figure of merit for anybody really trying to understand what unit to get.  Go with the COP and the operating temperature range.  Maybe there are some others here who can shed more light on this...

I have the 15RLS2H, and I can tell you that it cranks out a lot of heat, even at low temperatures.  I'm satisfied with every bit of it except a typically Japanese difficult user interface (especially in regards to setting up a timer schedule).  Realistically, you will likely get a bad user interface on any unit you buy, so I wouldn't let this get in the way of choosing the Fujitsu.


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## Wear More Layers

DBoon said:


> Hi Wear More Layers,
> 
> I have the 15RLS2H, and I can tell you that it cranks out a lot of heat, even at low temperatures.  I'm satisfied with every bit of it except a typically Japanese difficult user interface (especially in regards to setting up a timer schedule).  Realistically, you will likely get a bad user interface on any unit you buy, so I wouldn't let this get in the way of choosing the Fujitsu.



How much do you think you spend per year in electricity?  What's the elec rate in your part of NY?  I did a little research and learned that CT plans to increase fees on electric bills, and electric rates themselves are going to go up, too.   Yay CT.


----------



## DBoon

The rates vary throughout the year.  In winter, all-in, it is probably about 12 cents/kWh, and in summer 15 cents/kWh, not including monthly fees.  I know that CT has run way higher recently.  Once I get through this first winter, my solar array will be able to earn enough credits over the summer to power the heat pump for the winter while the house is unoccupied and in the (long) process of renovation.  In December, for instance, we had ~1200 degree days, and my consumption was ~800 kWh with the heat pump set at 60 degrees (constant).  I burned a little oil on the coldest days (maybe about 40 gallons).  The house does need insulation, and it is pretty leaky right now.  Lots of work to do.  

If you ran the heat pump just during the warmest part of the day (e.g. daylight hours), your COP would be better and cost/BTU less.  I think you will find that the winter cents/kWh rate is likely lower in the winter than the summer.  Be sure to ask if you are trying to justify payback on the system for heating use.


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## Wear More Layers

DBoon said:


> The rates vary throughout the year.  In winter, all-in, it is probably about 12 cents/kWh, and in summer 15 cents/kWh, not including monthly fees.  I know that CT has run way higher recently.  Once I get through this first winter, my solar array...



12 cents/kWh!!  That's just crazy.  I checked, and my rates don't go down in the winter.  There's every indication that electric rates in CT will only go higher, and one HVAC guy I know thinks I'm crazy for adopting a heat source that relies on elec.

Without going too far off topic, what are the advantages for you to have a wood stove, heat pump, and oil heat all in one home?


----------



## DBoon

Wear More Layers said:


> Without going too far off topic, what are the advantages for you to have a wood stove, heat pump, and oil heat all in one home?



Just to be clear - there are two houses that I write about, the one I live in today (wood stove, oil boiler with cast iron radiators) and the one I am going to be renovating (oil furnace, mini-split heat pump) and that is currently unoccupied. There is also a wood stove in the basement of the to be renovated house, but it is a slammer install and I wouldn’t consider running the wood stove it unless there was a seriously long power outage. 

The advantage in the house to be renovated is that the mini-split is set to run at 60 degrees and the oil furnace at 50 degrees.  If it gets too cold for the mini-split to cover the heat load, the oil furnace kicks in as a backup.  This oil furnace is old, and I am trying to minimize wear on it since I don’t want it to need expensive repairs before I replace it with a (likely) wood boiler.


----------



## peakbagger

A recent observation from cold weather mini split operation is the output varies with outdoor RH. If it is damp and snowing the units goes into defrost mode far more often than cold and dry for the same out door air temp. My unit is covered so the snow is not physically getting on it but RH really makes a difference.


----------



## woodgeek

outdoor RH is def a factor.  When it is >35 and raining, the outdoor coil is kept warmer than 35 and dry by the latent load, and you get more/warmer output.  Drop a couple degrees, and suddenly you are doing long defrosts during wet/snowy weather, and losing 20% or output.  (on a conventional split HP)


----------



## Dave A.

That was something that impressed me about the specs for the Hyperheat units.  The defrost cycle is limited to only a few minutes per hour iirc.  

But the way different mfrs handle defrost is an important consideration.  Was to me anyway when I was looking at regular split systems.  Eg. Goodman had one of the least sophisticated defrost cycles, controlled only by time -- i.e. would go into defrost regardless of whether it needed it or not.  Other mfrs have more sophisticated mechanisms eg. checking  temperature of the coils to see if there is frost build up or not.


----------



## peakbagger

An update on cold weather mini split usage, I have been running my one ton mitsubishi hyper heat  pretty much continuously since November 10th with it set at 65 to 68 degrees. I have only shut it down on nights when the expected temp was predicted to go below -5 degrees. As of today the unit has used 954 kWh for an average usage of 14 kWh per day. Generally when the temps are over 20 degrees day time with some sun  I can heat the entire house. Its a small home 952 sq ft on the main floor and 408 sq feet on the second floor office. As long as it is above zero at night and above 10 during the day it seems to be able to keep the main floor at temp but there is definitely some temp difference between rooms and my office loses out. I have been eating up net metered solar power to date so I still haven't bought any power and expect I can run another month before I run out of net metered credit. One of my solar arrays is on my roof and it was entirely offline due to snow cover for about half the period. It also only went on line in June so I didn't have a full sunny season to build up extra credit.

I have been running the wood boiler during the cold dark stretches mostly to supply heat to the office and heat domestic hot water.I have not run it for the past week but expect it will get fired up as the temps drop.  I originally used the heat pump less aggressively and went through a cord and half of wood since fall. My wood usage has slowed down with more aggressively use of the heat pump. I am definitely still in the learning curve mode. I think once I have a chance to see how much surplus electric power I can generate between spring and next season, I may elect to run the heat pump when the outside temp  is over 20 degrees to take advantage of the better COP and output at higher temps and use more wood.


----------



## Highbeam

peakbagger said:


> An update on cold weather mini split usage, I have been running my one ton mitsubishi hyper heat  pretty much continuously since November 10th with it set at 65 to 68 degrees. I have only shut it down on nights when the expected temp was predicted to go below -5 degrees. As of today the unit has used 954 kWh for an average usage of 14 kWh per day. Generally when the temps are over 20 degrees day time with some sun  I can heat the entire house. Its a small home 952 sq ft on the main floor and 408 sq feet on the second floor office. As long as it is above zero at night and above 10 during the day it seems to be able to keep the main floor at temp but there is definitely some temp difference between rooms and my office loses out. I have been eating up net metered solar power to date so I still haven't bought any power and expect I can run another month before I run out of net metered credit. One of my solar arrays is on my roof and it was entirely offline due to snow cover for about half the period. It also only went on line in June so I didn't have a full sunny season to build up extra credit.
> 
> I have been running the wood boiler during the cold dark stretches mostly to supply heat to the office and heat domestic hot water.I have not run it for the past week but expect it will get fired up as the temps drop.  I originally used the heat pump less aggressively and went through a cord and half of wood since fall. My wood usage has slowed down with more aggressively use of the heat pump. I am definitely still in the learning curve mode. I think once I have a chance to see how much surplus electric power I can generate between spring and next season, I may elect to run the heat pump when the outside temp  is over 20 degrees to take advantage of the better COP and output at higher temps and use more wood.



One ton as in 12000 btu? How is then noise level when the house is up to temp?


----------



## peakbagger

One ton is the nominal rating of the unit. One ton is 12000 Btus/hr . In reality the heat output varies with more heat as the temp rises and less as the temp drops.  

The noise level is variable, if I am heating the second floor office I have to run the fan at high to throw the heat over to a stair well and its noticeable (about what you would get in hotel room). If I am heating just the main floor I can run the fan at the middle speed.  I drop it down to low at night and the house is warm in the AM. The most annoying noise is when the unit goes into defrost as it has a variety of fan noise as it does its stuff.  Today its snowing out so its defrosting more often. Given the forecast for the next few week I will be running the boiler more often.


----------



## Dave A.

Interesting.  So you hear that inside the house when it goes into defrost.  Wondering how often and how long it's doing that.  Have understood there's no electric backup with these hyper heats, and they don't blow cold air during defrost, so it's just that you get no heat and there's an annoying noise in the defrost cycle.


----------



## peakbagger

_Interesting. So you hear that inside the house when it goes into defrost_.-  I live in a very quiet location in the woods, there really isn't a sound from the defrost as much as there is a variation in fan noise, it just cycles through a range of fan speeds from off to on. I expect those who play music in the background or are not sitting right near it wouldn't notice. I located mine to  optimize heating and that meant that the indoor unit ended up right near my Lazyboy chair. If I had located elsewhere I would notice it less.


_Wondering how often and how long it's doing that_. - Happens more often as the temp drops and the amount of the humidity in the air. On a sunny day in at 20 F, its very rare, add in snow or fog and it happens more often. In snow and fog I have turned it off around 10 degrees. No matter what as it drops down to zero, it starts to happen frequently.

_  Have understood there's no electric backup with these hyper heats, and they don't blow cold air during defrost, so it's just that you get no heat and there's an annoying noise in the defrost cycle. _You are correct that there I no electric backup. There can be draft during the defrost cycle as the unit does run the fan at a higher speed. With regards to noise I discussed it above


----------



## peakbagger

An update on my mini split. The various cold stretches have made an impact, I figured by now I would have 35 degree days and 20 degree nights (so do the maple sugar folks) but it has been getting down to zero or below. The mini split is cranking along. I am up to 1600 kw since Nov 11th 2013. I expect my net metering credit will be gone this month. I have cut my wood usage for my boiler which given the colder winters is good. I have pretty good sun exposure during the day so once the sun is up and the blinds are open, the heat pump usually goes idle by about 10:30 AM and stays that way until 4:30 PM.


----------



## velvetfoot

Electricity prices have been up this winter though.


----------



## flyingcow

velvetfoot said:


> Electricity prices have been up this winter though.





True. But so hasn't oil,propane, and even wood.


----------



## velvetfoot

But it's possible to store those commodities.


----------



## flyingcow

true. But with electricity you pay for after you use it.versus the commodities that you have to buy before you use it.some people prefer to use the money that way


----------



## DIrtyJersey

I do HVAC for a living. I have been installing Daikin mini-splits. Very nice stuff well made and many options.

http://www.daikin.com/global_ac/products_category/for_your_home.html


----------



## Seasoned Oak

Anyone have experience with Gree , they sell at Home Depot? THey have 3;levels of efficiency. Highest being 28.


----------



## peakbagger

Since I have effectively bought 20 years or more of electricity by installing PV panels to cover the mini split, I don't really consider electricity costs (although I may have to with in the next bill or two).


----------



## woodgeek

Seasoned Oak said:


> Anyone have experience with Gree , they sell at Home Depot? THey have 3;levels of efficiency. Highest being 28.



I saw some Gree units installed on a recent trip to Hong Kong.  Seemed popular (over there).


----------



## peakbagger

Cutting it close this month. I made it to my mid march power bill and I have 63 KW surplus left for a credit. If the sun is out and no snow on my arrays, I can generate 25 KWhrs a day. If we had normal temps this month I think I might squeak through the winter running the mini split for free but given the current forecast I am not so confident. About 1700 kWhrs run through the heat pump from November.


----------



## peakbagger

Knock on wood, my wood boiler has been shut down for the season since last week and my oil boiler is shut off. I am now running on the mini split  for all my household heat and my solar hot water is switched over to summer mode where the panels supply all the hot water with no backup on DC pump and solar panel. The PV system is supplying far more power than it takes to run the heat pump so as now I am running for "free" until October (I hope!).


----------



## velvetfoot

How does net metering work when you use the bank of kwh in a peak season, like in the dead of winter?  Do they give you full credit?  In NYS this winter, electric prices shot up a lot, maybe 50%.


----------



## Slow1

velvetfoot said:


> How does net metering work when you use the bank of kwh in a peak season, like in the dead of winter?  Do they give you full credit?  In NYS this winter, electric prices shot up a lot, maybe 50%.



I don't know about NY or other states, but in Mass, I get a $ credit on my account.  When I generate more than I use, the credit increases at the current rate; likewise when I use more than I generate I effectively "buy" the power at the current effective rate.  I'm on a fixed rate plan so it makes no difference to me for the most part (I end up at about $0.17/kwh either way), however if the plan rate were to go up in cost I'd effectively get fewer Kwh back than I 'banked' in the system... Same dollar value, but less utility.  Of course I get a $4.00/mo charge to be connected (quite a bargain for not having to buy batteries).


----------



## peakbagger

velvetfoot said:


> How does net metering work when you use the bank of kwh in a peak season, like in the dead of winter?  Do they give you full credit?  In NYS this winter, electric prices shot up a lot, maybe 50%.



It varies state by state, NH has about the easiest policy, I build up a KW credit not a dollar credit, as  long as I have KW in the bank, PSNH has to give me them back so the cost of power doesnt factor in. If you look at my meter in the fall it is negative and as the winter rolls along it slowly becomes positive. They didnt reset the meter when the system went on line so even though its positive I still may have credit. Since I am trying to sell SRECs, I also have a separate production meter that only records my generation that I installed.

PSNH has both generation and distribution and was not deregulated like other states. In a deregulated state I have no idea how they would manage it although some states do feed in tariffs. Net metering is a losing proposition for the utilities and they are fighting it in some states. In NH the law was written to encourage renewables up to 1% of the generation and then the program would be capped. They haven't hit that yet but it was one of the reasons why I installed an additional array as typically what the PUC does is "grandfather" a rate rather than eliminating it. The reality is that PSNH is just adding this effective subsidy for solar to the other ratepayers like they do all the other renewable incentives for wind and biomass.  

Other net metering states do a yearly gross up where they reset the KWhr credit to zero at a given date and pay the homeowner a wholesale rate for excess power. Some dont even pay for the excess. I can get paid for my excess once a year but its at a lower rate than residential so I would much rather run my heat pump.

In CA where there are utilities with tiered rates, some solar users are gaming the system to their advantage, they have a battery bank and sell all their solar power during the day including what is in their battery bank and then recharge the battery bank at night with low cost power. These battery systems are getting banned from net metering due to this.

In general there is much debate over net metering and feed in tariffs. Most of the New England States had renewable portfolio standards and the laws require a certain percentage of renewables over the course of year. The current rules are the utilities have to buy it whether they need it or not.  When compared to the long term wind contracts like Cape Wind that is reportedly near 30 cents a KW on a continuous basis, net metering is probably a better deal for them. 

Once NH starts allowing me to sell thermal SRECs for heating my house with a wood boiler, I expect I will have to relook at the whole concept again.

By the way, I pay about $12 a month for the utility to be my battery.


----------



## DBoon

velvetfoot said:


> How does net metering work when you use the bank of kwh in a peak season, like in the dead of winter?


Hi velvetfoot, in NY state, you get a yearly net meter based on kWh, not price.  The net metering starts when you get a PV system installed, and you can adjust this later.  If you haven't built up a kWh credit and you use more than you produce, you pay the difference at the retail rate. 

I had my net meter reset to begin May 1st.  But in retrospect, I think I should have had it started March 1st.


----------



## velvetfoot

DBoon said:


> Hi velvetfoot, in NY state, you get a yearly net meter based on kWh, not price.  The net metering starts when you get a PV system installed, and you can adjust this later.  If you haven't built up a kWh credit and you use more than you produce, you pay the difference at the retail rate.
> 
> I had my net meter reset to begin May 1st.  But in retrospect, I think I should have had it started March 1st.


So, if you had some kWh in the bank, earned when the price was lower last summer, you could use it when the prices went high this winter.  That's pretty good, because I don't think that's going to change for the next few years.


----------



## CaptSpiff

peakbagger said:


> <snip>
> In CA where there are utilities with tiered rates, some solar users are gaming the system to their advantage, they have a battery bank and sell all their solar power during the day including what is in their battery bank and then recharge the battery bank at night with low cost power. These battery systems are getting banned from net metering due to this.



Why would that practice be banned? It seems to accomplish exactly the goal of "peak shaving" that the time-of-day price structure is made to address, only on steriods.


----------



## woodgeek

They ban it because the utility lacks control on the process (which if widely adopted could lead to an unstable grid) and the profits made are not being made by them.

FYI, CA utilities are rolling out their own battery banks to do the same thing.  IOW, they don't want any competition.


----------



## Highbeam

woodgeek said:


> They ban it because the utility lacks control on the process (which if widely adopted could lead to an unstable grid) and the profits made are not being made by them.
> 
> FYI, CA utilities are rolling out their own battery banks to do the same thing.  IOW, they don't want any competition.


 
We do something similar with hydroelectric. We pump water up to a high lake during low demand times and then drain the lake through the turbines when demand is high. I say we but I mean the utility.


----------



## denjohn

DBoon said:


> In regards to why the HSPF of the RLS2H is worse than the RLS2, I asked the installer this same question.  He had no idea.  When researching HSPF, I came to the conclusion that the lower temperature units are penalized somehow since they operate over a broader temperature range, and naturally have a lower COP at lower temperatures since they still operate at those lower temperatures.  So I ignored the HSPF as a pretty "useless" figure of merit for anybody really trying to understand what unit to get.  Go with the COP and the operating temperature range.  Maybe there are some others here who can shed more light on this...



There seem to be a plausible explanations here:
http://www.revisionheat.com/the-latest-heat-pump-works-down-to-15f/
http://www.gogginenergy.com/tips-rants/article.aspx?id=24
It seems the H units are less efficient below 30* when a drain pan heater is activated.


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## rfin16

Did OP ever report on how the upper level unit in the hallway worked? We are thinking about something similar and have conflicting recommendations with some saying separate heads are needed for each room, while others are suggesting to direct one unit down the hall or install an ceiling mounted unit nearest to room doors. what is the potential for this type of setup to improve heat and cooling conditions in the upper level? Thank you for your feedback.


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## begreen

rfin, try starting a conversation with the OP to trigger an email to him. Also, maybe start a new thread and post a sketch of the floorplan(s) if you don't get a timely response.


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## begreen

DIrtyJersey said:


> I do HVAC for a living. I have been installing Daikin mini-splits. Very nice stuff well made and many options.
> 
> http://www.daikin.com/global_ac/products_category/for_your_home.html


Lots of Daikin systems being sold out here too. That is their global website. It's very thin on product info. You need to go to the North American site for better info:
http://daikincomfort.com/home


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## peirhead

You guys in the States have fantastic rebates on Solar Electric (PV systems).......even here in Canada a 5 Kw system is now under $20K without any rebates....perhaps it would be worth a look and what you can get there??? with your high CT electric rates it makes these systems even more attractive especially if you are thinking the heat pump route.


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## begreen

We heated the house in May with the heat pump with daytime temps in the 50s and 60s, nighttime temps in the 40s and low 50s. We also charged our electric car daily. Total electric bill was like $24. We expect in June for it to hit $0.00 or better yet, they pay us for that month in spite of our daily use of hot water, etc..


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## maple1

Buddy of mine had an LG put in, back in December.

After going through his power bills for the winter, he figures that overall it cost them about $1/day (at $0.18/kwh) to run it. He's in a Cape Cod, and they also run a wood stove when they are home. He had the LG set at 17c all winter, and were gone on a lot of overnight trips, and slacked off on the stove tending. They really like it - don't have to be a slave to the stove anymore or run out of bed in the morning through the cold to get it going .


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## DIrtyJersey

begreen said:


> Lots of Daikin systems being sold out here too. That is their global website. It's very thin on product info. You need to go to the North American site for better info:
> http://daikincomfort.com/home



Yes they are. I just threw that up so someone can see what options are out there. Just got done installing one in a home that has 4 zones. 2-2 ton coils and 2 -1 ton. Unit works great. With my cost all the parts involved. four line sets,4 condensate pumps, remotes,wiring and a few other bits. About 4900.00 my cost. Verses their quote to have duct work put into the tune of 40 grand. Big house.


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## STIHLY DAN

DIrtyJersey said:


> Yes they are. I just threw that up so someone can see what options are out there. Just got done installing one in a home that has 4 zones. 2-2 ton coils and 2 -1 ton. Unit works great. With my cost all the parts involved. four line sets,4 condensate pumps, remotes,wiring and a few other bits. About 4900.00 my cost. Verses their quote to have duct work put into the tune of 40 grand. Big house.



That is awfully cheap for 6 tons, you get great pricing.


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