# Getting a price to replace my 21 year old WaterFurnace GeoHP



## Jerry_NJ

I have been very happy with my Premiere Two speed 4 ton Geothermal (ground source) heat pump installed in 1993.  It started needing rather expensive repairs to replace worn out rotating machinery:  fan and loop pumps starting at about 15 years old.  When it needed a compressor repair last December I was happy to find a new dealer (the dealer who installed my HP retired a few years back) and repair man serving my area for Water Furnace.  He handled the repair in one visit.

I asked about replacing the then 20 year old compressor and he said Water Furnace no longer supplies a repair part for the compressor and no retrofit.  So, when that fails one will be faced with perhaps a week or more without HP heat or cooling (the HP has 34 KBTU resistive emergency heat, but that would run about $1 an hour to run, possibly $700 or more for a month of heat in cold weather).

I took a peek at the current line of Water Furnace and asked him to give me a price for a replacement of my unit with a 5 Series (Two Speed, not Variable Speed) heat pump.  I asked for a price with and without the ground loop pumping station being replaced.  My current loop pump station will work with the new 5 Series and it had its two pumps replaced 3 years ago.. they should be good for another 10 years. I estimate.   I also asked for a  price to replace my existing 10 year old electric water heater and the cost of equipping the 5 Series with a DSH (think that's the abbreviation) tap to feed HP hot water into my (new or existing) hot water heater.  My current system has the DSH but it never worked particularly well and that was in part to a poor design for the circulatory tap that was installed those 21 years back.  The current way to connect the HP and Water Heater looks to be more effective.  Water Furnace makes some rather high claims for savings on hot water using the HP... and of course with a COP of more than 4 and "Free" heat when cooling one could save significantly if the unit works as claimed.  

Interested in any inputs on current GeoHPs and specific inputs on the Water Furnace current line, especially the 5 Series.  

Interested on any neat "options" I should consider paying extra for.

I believe the replacement will qualify for the 30% federal tax credit, and I think there is a electric association rebate in the neighborhood of $500.


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## sloeffle

We have the Envision / 5 Series and have been very happy so far with it. It does supplement making hot water in the summer but you still need to run your hot water heater. I turn my the DSH ( de-super heater ) off when the temps are really cold to help keep my ground loops temps up.

Something that I was not aware of until this year is that you can order the furnace with a soft start option. I would highly recommend getting that if you plan on running the furnace with a generator. It drops the LRA from around 100AMPS to 35AMPS.

Have you looked at the 7 series ? It has a higher COP along with a  variable speed pump, compressor and blower motor.

http://www.waterfurnace.com/literature/7series/BR2700AN.pdf

Scott


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## Jerry_NJ

Thanks, my power outage strategy, and I had 10 days off-line when "Sandy" hit the East Cost a couple of years back (still have down wood I haven't cleared yet) is a low power generator to run the  refrig and a few CFL lights... and the blower on my airtight fireplace insert... and charge deep cycle batteries to use during the night and for periods of the gas gen being off.  I had trouble getting gas the the small engine and 1 gallon would run me several hours.

Thanks for the great input on the 5 Series.  I discussed the WF offering with the repair/installer/owner and asked about the life experience with the variable speed compressor - as noted my two speed is running 21 years now...with one repair to the starter circuitry last December.  He said not enough data to know on the variable speed, but he thinks the two speed is as good (better Scroll now) life expectancy as my current.  This is a bit at odds with my "notion" of what kills motors. start/stop but again, my two speed which was programed to go into Stage I at the first opportunity, is still running "like new".. but it isn't new (neither am I).  

I believe the 5 Series, even my Premiere 45 (21 yo) had the program set such that "Stage III" was shutting down the DSH, "State IV" was the run up on resistive supplement, two stages approximately 5KW then 10 KW (really a bit less more like 17KBTU). My old system, a 4 ton, was strong enough that even in our coldest winters I think the resistive (almost) never cut in to supplement the HP.

I'm yet to learn what the DSH cost, some of this stuff is clearly the "High profit" stuff and we pay top dollar for it.  The core has to be competitive the add-on like patents can draw big markups.  

I'd like to have more manual control, for example, when I use firewood to supplement heat the existing 3 speed fan will run only in low for the circulatory function, I'd like to be able to request the middle speed or even all speeds for circulation when the wood "stove" is running.


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## moey

If you get a DSH you must have a second tank ( buffer ) to realize any usefull hot water production specially in the summer. Also you may want to calculate if a 3 ton system will meet your needs.


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## Jerry_NJ

I don't understand the water tank concern.. I understand the potential advantage when there are occasional large demands for hot water.  My dealer suggested an 80 gallon single tank, and with only two old folks using the hot water that could act like a two tank system if we could turn off the bottom element.  The we'd have (approximately) a 40 gallon resistive heated fed from a 40 gallon HP driven pump.  The circulation I have in my current system is the DSH is feed from the bottom of the tank and returned to the bottom via the filler line.  That's how I modified my current unit - it was not the way that was used 20 years ago when both in/out was at the common drain port via a single coupling with a narrow ring to feed water back in.  My dealer asked if I put some kind of a valve in my return, via the cold feed, I said no.  He said one is needed, don't recall what it is, perhaps a valve that shuts off the DSH pump flow when the tank is taking in additional cold water.

Why a 3 ton, is the target to get a small as possible to gain efficiency, yes I understand dehumidification can suffer from a too large cooling power.  I really don't understand the Ton rating anyway as all unites are specified in BTH/H...and none have 36K or 48K (3 or 4 ton) in the listing and the cooling is always the higher of the ratings.  I'm happy to have a slightly oversized unit that runs a lot in Stage I (talking two speed here) as the additional capacity makes the lower speed extra high efficiency.  Have to go back to check, but I recall the 5 Series Water Furnace with a COP close to 5 in Stage I.  Ther trick I'd like to have is some override of the control board via the thermostat.  I'd like to be able to force the system to stay in Stage I as well as restrict/override the auxiliary resistive cut in ... say make the time delay for aux to be 1 hour, say.  This would allow recovering from a few degree set-back at night resulting in a hit of resistive heat in the moring when I ask for a 5 degree raise in the room temperature.  As for staying out of Stage II, I also use some "wood stove" wood heat and would like the HP to not go into Stage II when I am supplementing heat in one room.


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## moey

Efficiency in stage I and stage II are nearly identical. Most efficiency charts if you look closer at them have a higher incoming temp for stage I in the ratings then stage II. This does not happen when you run your system. You need to make comparisons at the same incoming temp.  I don't know why they do that. I dont know why you would want to shut off stage 2. 

If you shut off the bottom element on your tank off you'll have cold water when its 40F and sunny outside and the system is not running much. It just does not work well. The tank does not have a magical dividing line youll have cold water. Ive tried I have one tank it was a bad choice. In the summer you will not get free hot water with one tank. The summer DSH output is a much lower temp 100F or so having only one tank is useless because one element will keep that water on the bottom close to that temp. Also with a larger system it will not run long enough in the summer to make much hot water. It may even cost more as you lose heat checking the temp of your tank periodically. 

The smaller systems have higher efficiency ratings as well as a smaller blower. Of course if your load is 60BTU at 5F and you put in a 2 ton system youll have problems. You can run a a properly sized system be it 3 or 4 tons at less of a yearly cost then a oversized system. There is no debate on that. A oversize system costs more to operate. I know climatemaster has a tool to compare load on their systems. You can compare different systems when oversized the yearly cost is more then a system that deploys some electric heat. You do not get the stated efficiencies except in longer runtimes. 

I think most thermostats allow you to set temperature offsets Stage I is used until the temp falls X degrees from the setpoint then stage II then resistive heat. I do this in the spring and fall to get longer runtimes. 

geoexchange.org is good they are very helpful. Do some research dont assume because you had a unit that put out X btu that is the size you need.


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## moey

This is a spec sheet if you take a look at output for Stage 1 and Stage 2. The COP are calculated with EWT temp of 41F for Stage 1 and 32F for Stage 2. That is the reason for the different COP's between stages. In reality youll see very close EWT for both stages so your COP is about the same for each stage. I think they use the 41F so the industry can say they have a COP of 5 you may see that in Sept but not in January. 

http://www.waterfurnace.com/literature/5series/SC2500AN.pdf


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## Jerry_NJ

Moving forward on the Water Furnace 5 Series.  The 049 and the 038, both are two stage with variable speed blower.   My dealer's first proposal is for the 049.

I asked my dealer today to run both the 049 (4 ton cooling) and 038 (about 3.5 ton cooling) to see what the economics give. I'm sure the way I operate the 038 will work on heating too and will not call much auxiliary resistive heat even with a rated heating Stage II of only 26.7 KBTU. I like to run my wood stove fireplace insert on really cold periods. My house is a relatively small 2,000 sq ft two story built about 30 years ago for all electric heat. It has Anderson windows that could stand an update, but they are sound and double pane. My current unit has 40.5K Stage II heating capacity so the 038 could be working hard during a cold spell...running 24 hours a day. 

I was concerned and discussed with him that the 049 may have too much cooling capacity to get the humidity out in the summer. Its Stage I cooling is 41K BTU and I fear it will produce a cool damp house on short hot humid periods. Besides, running more at a lower BTU will increase the amount of hot water I get from the throw-away heat at the HP when cooling.

I was quoted with the 049 with DSH that adds over $1,000, I am surprised it cost so much. He said the cost/benefit run show about a $300 a year saving on hot water, so the DSH will pay off in a little over 3 years. I'm also quoted with a A.O. Smith 80 gallon hot water heater that will interface with the DSH. I have a working 50 gallon electric water heater, but my plan is to junk that heater (over 10 years old) and not keep it in series with the new DSH feed tank. We will call the new Smith 80 gallon the "buffer" tank, as well as the hot water tank. Here I wonder about good operating strategies. Does the DSH put out real hot water? That is if I have the HW heater set at 120 degrees will the DSH be able to pump heat into that environment, i.e., is the DSH output higher than 120 degrees? One strategy I used on the existing unit was to turn the water heater off when the HP was running a lot. Then if someone was going to take a bath or we were going to run the dishwasher I would turn the HW heater back on for that period, and off again as soon as our high demand for hot water stopped. This gave the DSH many hours of the day and all night to store BTUs in the HW heater as if it were a "buffer" tank. Sounds like a lot of work, but I like to "mess around" with stuff : )_

He's quoted with the ECM variable speed blower, Intellistart, Performance and Refrigeration package, and 10 KW auxil heat package options. I understand the performance package will give a lot of trouble shooting information, stuff I like to read myself such as the run time on aux heat, temperature of the brine in my ground loop and other operational parameters. The quote is with the TPCM32U03 thermostat. He also said the control board can be set for longer delay in starting the aux heat. I like to do a few degrees set back at night - like a cool bedroom and would like to be able to ask for a 5 degree increase in heat without the aux heat jumping right in. This operating mode may make the larger 049 more satisfying as it puts out (have to look up again, think about 40 KBTU  compared to 26.7 KBTU for the 038 and about the same as my existing Stage II heating).  

I haven't gotten a second quote, must be a Climatemaster and others in this area, but I like the Water Furnace I have, and I like the dealer who has done one expert repair on my existing unit last December. Before Tax rebate I'll be out about $16K as we will continue to use my existing ground loop and pumps. These two pumps were both replaced about 3 years ago. So, my after rebate cost will run about $11K. The new system should save me only a few hundred a year over my current system, but spares me the grief of having the old HP fail (compressor can not be replace) on a cold winter spell and have to rush to get a new installation. I know my old unit with a COP (when new) of 3.4 in Stage II will be well out done with a COP of 4.0 or better with either the 049 or 038 on Stage II. Besides, 21 years is a good service life for the existing unit, and it has paid for itself about twice in fuel cost savings (I paid about $9K with $3K more paid by Jersey Central Power). And I'm still using the vertical dual ground loop for a number of more years. That will be recharged as part of the new installation. 

My dealer says he can start work in about a week from the time I make a $5K deposit. It now looks like I'll go ahead for an early October installation. 

See any serious faults in my thinking?


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## DickRussell

[quote=".........My current unit has 40.5K Stage II heating capacity so the 038 could be working hard during a cold spell...running 24 hours a day./quote]

If the 038 runs 24 hr/day with no auxiliary at design minimum outside temperature, then that's just the right size. I'm not familiar with the ATP32U03's options, but it would seem that if it supported two levels of auxiliary heat, then it might be prudent to split that 10KW aux between say 2 and 8 KW, with the 8 coming on only in the case of true "emergency" heat, to avoid that big hit at COP=1 when all you need is a little increment beyond what the HP delivers when you are below design minimum outside. In my case, for my 2-ton Climatemaster Tranquility 27, with ATP32U04 tstat, I have three zones operated by a zone board, and the board allows two stages of aux. I put in the minimum 5 KW aux coil in the unit and a 1 KW in the outlet duct. The zone board treats the 1 KW as first stage of aux, adding in the 5 KW only if it really needs to. I've got the zone board set up to run that way, but I've no idea if it works, as my HP hasn't had to go to second stage unless I've monkeyed with the tstat settings temporarily.


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## Jerry_NJ

Thanks, the "half pregnant" idea did come to me.. using something smaller than the 5KW steps to the aux heat.  I know the proposed 10 KWATT aux/emergency heat isn't much heat.  My existing unit lost the compressor last December and with just Emergency heat of about 34KBTU I didn't' get a lot of heat. Hum, wounder why that's up in the HP range.  

My dealer called and said he ran the to sizes and put the results in the mail to me tonight.  I'll study them over but it is looking more like I'll stay with the 4 ton unit.  My only real concern is the cooling capacity may be too high, but then so is my current system in Stage II cooling, but it runs a lot in Stage I.  Current Stage I cooling is currently 27 KBTU the 049 is 41 KBTU and the 038 is 20 KBTU.   If my house was in the Washington DC area the 038 would be perfect as that's about the latitude were one needs as much or more cooling than heating capacity.

The other disadvantage of the 049 is less running time heating or cooling, thus less hot water at a COP of 4 or better and free when cooling.  

I asked about the proposed system and he said the thermostat can set the Stage III delay to 30 minutes, which could allow me to run the 049 at a lower heating temperature at bed time, my preference and still have a hope of recovering the 5 degree set back from just Stage II (37KBTU).  I also have a fireplace (wood stove) insert that I like to start on a cold morning to help bring the house temperature up.

I also discussed the proposed 80 gallon electric water heater for a combined "buffer" and Hot Water tank. He said that'll would we just set the lower thermostat as low as it will go, then the upper at 125 degrees if that's what we want.  I'm considering disconnecting the lower heating element.  We currently have a 50 gallon water heater and never run out of hot water.  This idea assumes the temperature stratification in the water heater will feed the DSH with cooler water in the lower half, thus turning the lower half into a "buffer" holding area.


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## moey

Jerry_NJ said:


> I also discussed the proposed 80 gallon electric water heater for a combined "buffer" and Hot Water tank. He said that'll would we just set the lower thermostat as low as it will go, then the upper at 125 degrees if that's what we want.  I'm considering disconnecting the lower heating element.  We currently have a 50 gallon water heater and never run out of hot water.  This idea assumes the temperature stratification in the water heater will feed the DSH with cooler water in the lower half, thus turning the lower half into a "buffer" holding area.



Setting the lower thermostat as low as it will go will not work. I can say that from first hand experience with a 80 gallon tank. I tried... You end up with luke warm water.  You need two tanks to realize any gain with a DSH. The tank does not stratify like one would hope. If your not getting two tanks save yourself the money and dont get a DSH.  Its unfortunate the geo companies and suppliers push the one tank setup presumably to sell more DSH.


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## woodgeek

Re the over-sized cooling....I am running a single speed 4 ton ASHP for heating and cooling not far from you.  With 47kBTU/h cooling on a 2250 sqft house, it initially never ran more than 10 hours a day.  

When I first got the system, I often had problems with excess humidity, mostly during the fall when the outdoor humidity was still high, but the outdoor temps had fallen. To deal with that I had the stat set to 'supercool'....if it detected humidity above some setpoint, like >60%RH, it would cool below setpoint as much as a few degrees.  Not always super comfortable, but it worked.

Part of my problem is that my site is heavily shaded, no sun loads, and my finished basement is uninsulated....so lots of 'earth tempering'.

Since then I have (1) repaired bathfans for shower humidity and (2) airsealed the house, getting it to ACH50=5, and now excess humidity is not such a problem.  I cruise around 50%RH all summer.  With the airsealing and insulation work, my AC now never runs more than 7 hours a day (when its 100°F all day).

I would still like to get to lower %RH, I am planning on setting the CFM of my variable speed blower a bit lower for AC mode than it is currently....that lower the coil temp, and improves dehumidification.  *I would ask your installer about this option now.*

So, you have options if there is too much RH....stat settings for super-cooling, source humidity control (fans), getting your house airsealed, summer blower CFM, etc.  You're not the first person to have this issue.


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## sloeffle

We have the 049 with the ECM variable speed blower, minus the Intellistart . It heats and cools our 2200 sq ft ranch without any issues. I never hooked my heat strips up to the electrical panel because I don't want to pay for them to run. I figured the cost out one time and I think it was around 3.40$ and hour. Not sure if that was a good decision or a bad one. It burned me one time last year when it was really ( -10 to -20 ) cold but I just told the wife and kid to tough it out until I get the wood furnace going.

We do not have the buffer tank and my HVAC installer told me to turn off my bottom element on my hot water heater also. We ended up with luke warm water also.

If you are looking for a new hot water heater, I would look at the ASHP hot water heaters. Lots of talk about them on this site. If you are do not like the idea of a ASHP hot water heater then I would look into getting a Marathon. They are made out of plastic and have a lifetime warranty on the tank.


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## woodgeek

agreed on the HPWH.  Figure a seasonal-average COP close to 2 in our area, and price it accordingly, with available rebates.  If the DSH adds to the system cost and requires a second tank, its seems a HPWH is a better buy.


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## moey

sloeffle said:


> We have the 049 with the ECM variable speed blower, minus the Intellistart . It heats and cools our 2200 sq ft ranch without any issues. I never hooked my heat strips up to the electrical panel because I don't want to pay for them to run. I figured the cost out one time and I think it was around 3.40$ and hour. Not sure if that was a good decision or a bad one. It burned me one time last year when it was really ( -10 to -20 ) cold but I just told the wife and kid to tough it out until I get the wood furnace going.



Not a bad idea to hook up the electric coil. Most thermostats you can basically program them out so they will not come on. At least mine you can set a temp offset of 10 degrees or so and also set the number of hours it would take of not maintaining a temp before the electric heat comes on. All it takes is for you to be away on vacation and have the HP quit for you to have frozen pipes.


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## woodgeek

You could also wire the aux's into the breakers, and just switch the breakers to off.  If you are going out of town, turn them on while you are gone.


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## sloeffle

woodgeek said:


> agreed on the HPWH.  Figure a seasonal-average COP close to 2 in our area, and price it accordingly, with available rebates.  If the DSH adds to the system cost and requires a second tank, its seems a HPWH is a better buy.


Good point. Just use the 1000$ from the DSH and put it too a HPWH. WIth gov't rebates you will probably be further ahead since it makes hot water year around vs summertime with a DSH.


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## woodgeek

On further thought, the HPWH will deliver cheap DHW all year long, because even in the dead of winter, it will be stealing cheap BTUs from your geo.  Your total COP, even including heat stealing, could be 1.5-2 even in the dead of winter.  I am sure you can get a Geospring, after rebates (with an extended warranty) for little more than a second tank costs, and just keep the DSH $1000 and the annual energy savings going forward.


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## sloeffle

moey said:


> Not a bad idea to hook up the electric coil. Most thermostats you can basically program them out so they will not come on. At least mine you can set a temp offset of 10 degrees or so and also set the number of hours it would take of not maintaining a temp before the electric heat comes on. All it takes is for you to be away on vacation and have the HP quit for you to have frozen pipes.


I could not agree more. I believe the HVAC guy set mine for 10 degrees also.

It has been on my todo list for about 2 years. Wiring them up is a lot harder than just running some wire across my basement. We only put a 100 amp panel in my house addition and the heat strips require 120 amps / 20kW if I remember right. So the wiring would need to snaked through a crawl space in conduit, up a wall and into the 200 amp panel in my house.

Not a fun job.


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## woodgeek

In retrospect, I wish my 15 kW aux coils were a lot smaller to give better comfort control when they are cycled on.  They were sized for EM heat, now 10 kW would do the job 99% of the time.  I could even go 8 kW and stash a couple cheap space heaters in the garage in case of (really unexpected) need.


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## moey

sloeffle said:


> Good point. Just use the 1000$ for the DSH and put it too a HPWH. WIth gov't rebates you will probably be further ahead since it makes hot water year around vs summertime with a DSH.



Ive thought about this. I have a DSH and one tank so Ive considered putting the HPWH as my buffer tank use the HPWH for 9 months of the year and the DSH for the other 3 months. In retrospect I wish I add not gotten a DSH and gotten a HPWH but I drank the koolade given to me by climatemaster and my installer.


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## woodgeek

sloeffle said:


> I could not agree more. I believe the HVAC guy set mine for 10 degrees also.
> 
> It has been on my todo list for about 2 years. Wiring them up is a lot harder than just running some wire across my basement. We only put a 100 amp panel in my house addition and the heat strips require 120 amps / 20kW if I remember right. So the wiring would need to snaked through a crawl space in conduit, up a wall and into the 200 amp panel in my house.
> 
> Not a fun job.



Strips are pretty cheap.

You could swap out the 20 kW strips for something smaller, and make the wiring job easier.  20 kW is 'only' 80A, or 100A wiring and breaker.  10 kW would be plenty for aux heat and useful for emergency heat, and only need 40A, or 50A wiring and breaker.


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## sloeffle

moey said:


> Ive thought about this. I have a DSH and one tank so Ive considered putting the HPWH as my buffer tank use the HPWH for 9 months of the year and the DSH for the other 3 months. In retrospect I wish I add not gotten a DSH and gotten a HPWH but I drank the koolade given to me by climatemaster and my installer.


I drank the kool aid also, so don't feel bad.


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## Jerry_NJ

Very interesting, I too drank the Koolaid 21 years ago when they didn't have a workable tap for the water heater and just tapped into my existing, which was 80 gallon.  I somehow can't shake the attractive image of getting "free" hot water at least when cooling.

I'll talk more, maybe read the instructions, but more manual control at the thermostat is better than smaller resistive elements in my "book" I like wood heat so having to assist the HP in an unusual lower temperature turn would fit me just fine.   I had the back up strips disconnected, disconnected the relays that cut them in.  I could reconnect time in a matter of minutes for an emergency... but I prefer a "soft" or "Program control" approach.


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## moey

Jerry_NJ said:


> Very interesting, I too drank the Koolaid 21 years ago when they didn't have a workable tap for the water heater and just tapped into my existing, which was 80 gallon.  I somehow can't shake the attractive image of getting "free" hot water at least when cooling.



The problem with the free hot water analogy in the summer is you only get 100ish degree water the compressor pressures are not high enough to make hotter water. The system also has to be running no free lunch when its a high of 75 outside unless you want your house 55 F inside. I think I ran my A/C maybe 10-15 times this summer and that is with it set on 70F which most people would feel is pretty cold. Of course you live further south then me we only had a couple 90F days.


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## Jerry_NJ

I'll talk with my Water Furnace dealer to see if also installs HPWH.  He does go some on his "own" as the proposal includes an 80 gallon A.O. Smith electric water heater which he sources outside Water Furnace.  

An interesting item I think I picked up on this thread is more control of the blower.  I currently have a 3 speed fan which is dedicated as follows:  low = demand circulation (under my control to turn on/off )  medium = Stage I operation and high = Stage II and Emergency operation.  If the variable speed and the new thermostat makes it possible for me to pick a higher than low speed for circulation it would help a lot in my battle to distribute wood heat.


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## moey

I wasn't trying to dissuade you from a DSH they do work well when setup up properly two tanks etc.  You just really need to get the maximum out of them to recoup your costs. They probably have a longer life then a HPWH too.


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## Jerry_NJ

Checking Geospring on Amazon I see it runs about $1K and it has very poor customer evaluations... never mind the second part for now, wouldn't the fact that the HPWH is dumping cold air into (my case) the basement, does it have a drain for removing condensation?  Wouldn't that help dehumidify the basement in the summer, as well as help to cool it?  Looks to me we have a couple of wins beside sufficient hot water with a COP of , what? better than 2?


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## woodgeek

yes, HPWH's provide cooling and dehumidification of a basement for 'free', and do require a condensate pump/drain.  COP in warm basements is prob ~2.5 heating water to 120°F.  The Geosprings have terrible reviews online, but we can't find anyone on Hearth.com who has had a problem, just many satisfied customers. Idea seems to be to buy the extended labor warranty (part warranty is included), and cross your fingers.  Are you running a dehumidifier in the basement, or tying it into your AC?


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## moey

There are several generations of GeoSprings the first generations had bad reviews. They newer generations have much better reviews or far less negative reviews.


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## Jerry_NJ

Thanks, I run a dehumidifier part time in the summer, I prefer to run an exhaust fan.  I have a good quality fan that sits on the floor and vents through a basement window.  If I remember I turn it on when the outside temperatures are dry -  a dew point below 50 degrees.  I will let it run over night and try to provide air from upstairs rather than draw from around my floating slab.  

I did consider that the hybrid water heater would not hold up like my existing Water Furnace, which has the DSH, but I quit using it when the aux pump failed.  This failure also brought an end to the dealer I called for repair.  He misdiagnosed the problem and replaced both of my loop pumps - there was some common fuse, don't recall the details any more.  This was then "covered up" by sticking me with new pumps running 24/7 I heard them running is how I discovered the "error".   When I got the schematics and diagnosed and tested my theory I called him back, we as very willing to make things "right" but I then looked for a new dealer and may have never purchased a WF again, but I found a dealer I believe is very competent as was the dealer (since retired) who installed my WF 21 years ago.

Can anyone point me at a good thread on the Hybrid Water Heater (heat pump)?  Yes, I know how to use search, but someone active here may have a favorite thread.  I'm not sure how the HPWH develops such a high (150 degrees?) temperature.  But given it can it is easy to see that it could also produce considerable BTU. If a COP of 2.5, that would be only 1,800 watts and should be well within the existing circuit capacity delivered to a WH using 4,500 watts.  What's the strategy on the HPWH, does it still call in resistive heat when it can't keep up with demand?

I left a message with my dealer asking if he also installs HPWH, and if so I "have" about $2,200 I could transfer from the current plan taking away the new 80 water heater and the DSH.  I understand I would be able to seek the same US Gov rebate of 30% for the HPWH.


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## sloeffle

If you do a search in the top right hand corner for geospring. You should find the various threads.

I personally am not a big GE fan. Their are plenty of other companies ( Stiebel Eltron, Rheem, A.O. Smith ) that make HPHW and would be worth looking into.


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## Jerry_NJ

My Water Furnace dealer likes A.O. Smith for regular electric water heaters so if he installed HPWH they may be Smith.


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## woodgeek

I have the 80 gal AOSmith HPWH, 2.5 years in, 100% Chinese made, no problems.  I have two teen girls...the Smith runs the shower for 90 minutes or so straight in HP only! Ask me how I know.  It would be overkill for you, as would the 60 gallon I suppose.  The 50 gal Geospring costs almost half as much after rebate, IIRC

The COP is ~2.5 heating water to 120°F from a 70°F air source.  Higher water temps are not recommended (scalding or tempering valve required).  Lower temps could allow pathogens, hypothetically.  120°F is perfect.  It achieves the higher temps by using a different refrigerant, HCFC-134a, if I recall, rather than R-22 (now phased out) or R-401a (for newer ASHPs and geos) aka 'Puron'.

When you decomission your geo, have them recycle the R-22 rather than vent it, the earth will be grateful.


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## DBoon

You can realistically get a COP of 2.25 heating water to 120 degrees F with a 60 degree basement temperature.  If you try to heat to 130 degrees F, I would estimate that COP is a little below 2, and at 140 degrees F maybe only 1.5.  

I was much more satisfied with my Nyle HPWH once I 1) superinsulated the supply and return lines from the HPWH to the tank, and 2) lowered the water temperature to 120 degrees F.  Run time decreased by about half with the reduction in temperature.  

If you get an all-in-one HPWH, you don't have the issue with superinsulation of supply and return lines.


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## Jerry_NJ

I haven't gotten any response yet to my telephone message with my dealer asking about a HPWH in place of my DSH and 80 Gal electric/buffer tank combined.  But I got some interesting numbers from his "Geolink Project Report" for the two size GeoHPs I am considering..  and I think I may be the most happy with the smaller.  This run assumes a DSH and functioning buffer and hot water tank.  For the 3.5 Ton and 4 Ton the DSH is rated at a mere 1,300 BTU/H or about 380 watts (roughly)... so the recovery is very slow when the resistive HW heater element is not running.  

The run is for the temperature range 2 degrees to 97 degrees external with 70 degrees and 75 degrees, respectively for inside temperature.  Of course at for the 038 HP (3.5 ton) resistive auxiliary heat is required.   The model expects to see 2 degrees for only 5 hours total and requires 13 KWH of aux heat... this is only 2.6 KW average.  This says to me I want the two stage resistive heat to be one 2 KW and one 8 KW.  Moving up the temperature scale the model expects to see 30 hours at 7 degrees and a use of 48 KWH of resistive heat.  That's only 1.6KW average which means only the 2 KW or Aux heating element will see use, and not full-time.  The 8 KW will see very little use unless there is a need for emergency heat (loss of the HP).

This is the area I was most concerned about for the smaller unit, the 049 uses no aux heat, zero.  Given I'm a "Minister of Fire" on this family of forums it is obvious I have not problem using some wood heat.  I have about 2 cords covered and ready to burn right now.

In total the estimated operating cost including Hot Water for the 3.5 Ton is $1,423 and for the 4 Ton $1,549, or I save about $100 per year with the smaller unit and dryer air in the during the hot/humid NJ weather.  Both units have enough to handle the 97 degrees and there is no aux cooling to call in, so good thing.  Interestingly the smaller unit at 87 degrees (for the model time at that temperature) uses 302 KWH while the larger unit uses 331 KWH or almost 10% more energy, because the smaller unit is running almost 100% of the time in Stage I with an EER of 30.

Many other interesting numbers, and I don't know what my price is with the smaller unit, but I assume less.   

I remain undecided on the DSH/80gal Buffer/Heater.  I've gotten a lot of negatives on that operational mode, but I still feel running the 80 gal with the lower unit off or set as low as it will go will provide me much the same as a 40 gal buffer and a 40 gal hot water heater in series.   As said somewhere, when I'm home and the HP is running anywhere over 50% of the time I'll switch the HW Heater Braker off.  I'm of the opinion from the above that the DSH should be able to bring the the tank (or maintain) to 120 degrees with no resistive heat used in the tank.  With only two senior age adults most days the tank will not see any one hour draw above 40 gallons.  Wild guess, I think my shower is more like 5 gallons of hot water, my wife's maybe 10 gallons.  The dishwasher is a newer high efficient unit and it takes over a hour to wash the dishes in "darn" little hot water.

Hope not too many typos - I appreciate communicating clearly is the only way to get the usual great help.  But, it is now 11:25 PM and I'm tired.


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## woodgeek

OK, if I recall, we had a whole discussion last year re whether you would downsize to a 3 ton unit, and I think we concluded that the step to 3 tons was just too much, and you would call too much aux.  Just based solely on that memory, I could believe the 3.5 tons is 'ok'.  You have extensive experience with the 4 ton, and know it always or nearly always kept up (right) so dropping 12% is not going to be a world of difference (versus dropping 25% to 3 ton).

Suppose that the balance point was previously 10°F for the 4 ton, heating the inside to 70°F, or 60° Delta.  The 3.5 tone will only heat 60° *(3.5/4) = 52.5°, so you new balance point will be 7.5° higher, or 17.5°F.  Now, there is a lot of lag and thermal inertia in BTU loads, so if you drop to below balance point for only a few hours, you may never even call aux at all.

One analysis is to look at heating done right at the 4 ton balance point, so your aux btu demand goes from 0 with the 4 ton to 12% with the 3.5 ton.  Your new COP is rather than 3 (for the geo), actually 3 for 88% of BTUs and 1 for 12%, my math gets you an effective COP of 1/(0.33*0.88 +1*0.12) = 2.43, or you are using 23% more power at that temp.  So, at whatever balance temp you had before....you will now use 23% more energy at that same temp with a 3.5 ton.  IF your balance point previously was close to your ave January temp (say 28°F), the 3.5 ton would boost your energy bill 23%.  If your balance point was -10°F, and now it is closer to 0°F with the 3.5 ton, you will use no extra energy with the 3.5 ton.  The truth for you is certainly between these limits.  0% more to 20% more.  IF it was 10% more, (maybe $100/yr) does the lower up front price make sense?  Maybe the AC dehumidification is worth $100/year in comfort (not energy), but it still seems the right answer might be a 4 ton two speed (like you have now).

I really think certainty on this point is going to be elusive....that would require some empirical knowledge re 'balance point', at what sustained outdoor temp the 4 ton could just keep up.  Any estimate I or your installer comes up with will be very uncertain relative to that datum.  Do you have a number in your head, where you noticed aux coming on??

And those demand hour tables that the installer generates are decadal averages. That 5 hours at 2°F...that means 50 hours one year, and then 0 hours in the next 9, on average.  They are not useful without balance point info....any calcs he makes are assuming some balance point....and it could be garbage in garbage out.

Phew....DSH/HPWH will have to wait...


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## sloeffle

My math skills are no where near woodgeek's so I will give you the philosophy on why I went with a 4 ton unit over a smaller unit.

I debated the same thing with my HVAC until he brought up a interesting point. Yes, the cost of a 4 ton unit is more expensive than a 3.5 ton unit. But by going to a bigger unit you will run first stage ( 2 tons / 22 amps ) heating and cooling more vs running in second stage ( 4 tons / 35 amps ) or aux heat ( 3.40$ and hour in my case ) . My GSHP has never hit second stage in cooling mode and I only hear it kick into second stage heating generally when we wake up in the morning and the thermostat ups the temperature.

In Ohio we do a lot more heating than cooling so the dehumidification effect of going to a smaller furnace IMHO is not worth it. I would assume that New Jersey would be the same.


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## Jerry_NJ

Hum, I don't recall discussing this last year, but I am sure I was considering a voluntary replacement that far back.  The not too expensive, $450, repair last December and the news a new compressor would not be an option got me more serious on the replacement subject. 

The computer program (factory/Waterfurnace) didn't give cums on Stage I and Stage II, but the data can be harvested out of the time for each external temperature.  My estimate is the 3.5 Ton (38KBTU Cooling max, closer to a 3 Ton it seems, even less heating at 28KBTU Stage II) runs a lot in Stage I also.  Yes, the weather is similar to OH, we lived in Granville for a number of years in the 70s (near Columbus), but there we did see some 25 degree below zero and the natural gas furnace had trouble keeping up. Yes, that was unusual. 

Interesting, perhaps, the program provides total run times for the given model of 695 cooling and 2648 heating for the 3T and 528 cooling and 1942 heating for the 4T.  But, the COP of the 3T is higher - and that doesn't take into account my ground loop was designed to support a 4T which says to me the loop temperature will be more moderate (efficient) with the 3T.  My/our plan is to reuse my recently rebuilt loop pumping station but run its two pumps for both Stage I and II, currently the system runs only one pump for Stage I.  It may be possible to run just 1 pump for both stages with the 3T unit. 

Some of the design numbers:  Delta T, 70 degrees heating, 20 degrees cooling (max), Hot water Temp setting 130 degrees (this one needs some explanation), Internal gains 8,400 BTU/H, this too needs some explanation - what cooking?  Maybe real geothermal, we're on a ground fault : (

I have been looking at the 3T for heating/cooling cost/benefits not initial cost.  If the 3T is $1,000 less that would be another big advantage for me.  I can not see any way I will live in this house even 5 years more.  A $200 a year average spending of the savings would cover any aux heating needs.  Here, did I say, I am thinking for the two stages of resistive heating:  2 KW aux, 8KW emergency, with either 3 or 4T.  And, I will not feel I am pulling any dirty tricks on the next owner who will have a geothermal (gs) hp that is near new and much more economical than an oil furnace and air to air AC unit.   Of course, if we get the promised "electric rates will necessarily sky rocket" the economics could shift the other way.  Then too there seems to be an effort to make the cost of oil/gas sky rocket too.  Of course oil has already.  When I put in my first Geo in 1993, heating oil was about $1 a gallon and electric in NJ was  about 10 cent KWH.  Now heating oil is $3.50 or more and electricity is 15 cents.  That's what made my decision to go Geo a wise one.  Then too, I had to depreciate a heating system that cost 3 or 4 times as much.  I'm still depreciating the ground loop, and put the HP with installation and maintenance/repair at about $600 to $700 per year depending on when the ground loop fails.  Whats maintenance on an oil furnace?  Must be $200 a year just for cleaning and adjusting... bur I digress, yet all these factors play in the economic modeling.  Iin fact Just Like Geo (GS) HPs.


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## moey

Folks curse at electric heat coming on to much. But the thing to remember is if its coming on when its 10F outside that means you saved money earlier in the year when it was 35F and you were not running such a oversize unit for that temp and short cycling. You only realize the COP of 4+ on long runs so if a unit is cycling for 5 minutes when its 35F out your losing out on savings. 

One of the biggest arguments for smaller vs larger units is the cost to drill/dig you already have that part paid for. 

Theres a writeup somewhere on this house http://welserver.com/WEL0478/ online at geoexchange.org I cant find. It basically a house with 50K btu heat loss that has a 3ton unit installed in it. The ductwork would have needed upgrading and more digging so they opted for a small unit. The yearly cost difference was in the $10-$20 range a difference that would never be made up.


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## woodgeek

Jerry_NJ said:


> Hum, I don't recall discussing this last year, but I am sure I was considering a voluntary replacement that far back.  The not too expensive, $450, repair last December and the news a new compressor would not be an option got me more serious on the replacement subject.



I was thinking of these threads...  
https://www.hearth.com/talk/threads/i-am-thinking-about-replacing-my-20-yo-waterfurnace.124456/
https://www.hearth.com/talk/threads...ier-at-compressor-out-time-to-replace.119434/

To wrap it up, the downsizing calc is doable IF you knew or otherwise estimated a balance point for the existing system, not otherwise.  If you really think the aux comes on very rarely, then the existing unit IS oversized from an economic point of view (mainly meaning the loop cost more than it had to 20 years ago).  With the 4-ton loop as a sunk cost, however, it seems the marginal cost of a new 4-ton is small.  Downsizing will not be likely to increase your (small) elec bill more than 10-20%.  And the smaller unit will like the bigger loop, re loop temps.

The next owner can/will improve the insulation and airsealing of the house, IF he/she cares about the heating bill, and the balance point will drop back down to eliminate aux.  Not your job on a 5 year horizon.  If you went 4 ton single speed, when the next guy airseals and insulates (hypothetically) the new unit gets even more oversized.  E.g. based on BTU loads I should have gotten a >5-ton ASHP when I installed 6 years ago, and I ran a lot of aux while I improved my house envelope.  Now my 4-ton is perfectly sized for heating.

That said, I agree that you DO want two-speed for comfort and dehumidification...and heating in stage 1 is prob nice and quiet....has good balance too, etc.  I think comfort, summer and winter, should drive the final decision and don't worry about downsizing a bit.

Re the DSH....I am no expert, but I think it is a complex, expensive white elephant.  I would listen to sloeffle that a 1-tank solution will not be happy....your effective HW 'capacity' will be much less than 1/2 the tank volume.  You and the DW might 'get by', but the next family with kids will curse the lousy hot water when they want 5x as much DHW as you do.  Going to 2 tanks is both expensive, takes up a lot of space and provides more points of failure.  And then at the end of the day, its not efficient. DSH can't lift to high temps efficiently by itself, and using an element to 'finish' heating the water seems wasteful.

In the 1990s, 'free hot water' must've sounded great.  Guess what...when I switched from oil DHW to my HPWH, my annual elec bill actually *fell*.   Scrapping my boiler saved me a ton of AC, and I eliminated a dehumidifier....so even with 2 teens I still have 'free' hot water.  HPWHs are the wave of the future, in a couple years all elec units bigger than 50 gal will be required  by existing law to be HPWHs (like the light bulb ban).  From an engineering POV, get a system designed (with a different refrigerant) to efficiently heat DHW, rather than get a complex kludge that tries to do it with a system optimized for other HVAC purposes...and then dump the whole thing on the next owner.


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## woodgeek

Jerry_NJ said:


> And, I will not feel I am pulling any dirty tricks on the next owner who will have a geothermal (gs) hp that is near new and much more economical than an oil furnace and air to air AC unit.   Of course, if we get the promised "electric rates will necessarily sky rocket" the economics could shift the other way.  Then too there seems to be an effort to make the cost of oil/gas sky rocket too.  Of course oil has already.  When I put in my first Geo in 1993, heating oil was about $1 a gallon and electric in NJ was  about 10 cent KWH.  Now heating oil is $3.50 or more and electricity is 15 cents.  That's what made my decision to go Geo a wise one.  Then too, I had to depreciate a heating system that cost 3 or 4 times as much.  I'm still depreciating the ground loop, and put the HP with installation and maintenance/repair at about $600 to $700 per year depending on when the ground loop fails.  Whats maintenance on an oil furnace?  Must be $200 a year just for cleaning and adjusting... bur I digress, yet all these factors play in the economic modeling.  Iin fact Just Like Geo (GS) HPs.



The average cost of electricity in the US has been flat or falling, corrected for inflation, for 30 years, (as your numbers show). Current projections from the EIA and many market analysts are for that to continue into the foreseeable future.  Cheap wind, cheap (for now) natural gas and flat or falling demand are putting a ceiling on the price generators can get for power, and the falling price of solar PV will apply even more pressure in the future.  A highly efficient, electrically-powered HVAC system will be 'future-proof' for the next owner, and will likely be running on mostly or 100% renewable energy well before it wears out in *2035*.


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## Jerry_NJ

Okay, guilty as charged, yes I was thinking this subject immediately following my last December repair and the news that a new compressor is not available for my current unit.

I had just about decided to give the DSH another try.. now again I wonder.

I looked at the tax rebate form (one contributor gave a link) and I didn't see a line for HP WH, but somewhere I saw there is a $300 rebate/credit - need to verify that as that would be another plus for the HP WH.


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## woodgeek

I think we the fed rebate for HPWH was part of the big package several years ago that had a cumulative cap....I exhausted the rebate with other things, and now its gone??  I did get $300 from my utility, and I think most utilities are providing a rebate these days.  Note that I was not replacing an electric tank either.


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## woodgeek

OK, after a little Google fu, I found:

http://www.njcleanenergy.com/residential/programs/warmadvantage/gas-water-heaters

that seems to say a HPWH is eligible for a *$500* rebate from the state of NJ if installed before June 30, 2015.

It seems that rather than have the utilities pay this out individually, it is out of a central, state office.


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## Jerry_NJ

Thanks, I see a connection to what my dealer said, something about I get $500 from some fund associated with the power companies, not government.  He didn't explain and I didn't ask.  Looks like it is for the DSH hot water.  He said he'd apply for that "refund".


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## woodgeek

Jerry_NJ said:


> Thanks, I see a connection to what my dealer said, something about I get $500 from some fund associated with the power companies, not government.  He didn't explain and I didn't ask.  Looks like it is for the DSH hot water.  He said he'd apply for that "refund".



I did not see any DSH on that link, but I did see HPWHs.  ??

I would think you would apply for the rebate yourself, not your installer.


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## Jerry_NJ

Thanks, I'll give it a closer look.  You may have introduced me to a new "pay off" to encourage being more "green" : 0 )   As already noted, I've been using a Geo (ground source) HP for over 20 years.   Unfortunately, my past experience with DSH wasn't good.


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## woodgeek

I think the new geo w/o DSH and separate HPWH should work better and could be more efficient than your sol'n 20 years ago.  The geospring all in one will be cheap to install, not complex or 'weird' to techs that will work on them in the future (i.e. they are sold off the shelf in Home Despot), and will score a $500 rebate from NJ.  At 50 gallons, it will provide plenty of nice DHW for two older folks in pure HP mode.  If more water is ever needed (e.g. by subsequent owners) they can press a button to go to hybrid mode, in which the unit will switch to an element when faster recovery is needed.


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## sloeffle

moey said:


> Folks curse at electric heat coming on to much. But the thing to remember is if its coming on when its 10F outside that means you saved money earlier in the year when it was 35F and you were not running such a oversize unit for that temp and short cycling. You only realize the COP of 4+ on long runs so if a unit is cycling for 5 minutes when its 35F out your losing out on savings.
> 
> One of the biggest arguments for smaller vs larger units is the cost to drill/dig you already have that part paid for.
> 
> Theres a writeup somewhere on this house http://welserver.com/WEL0478/ online at geoexchange.org I cant find. It basically a house with 50K btu heat loss that has a 3ton unit installed in it. The ductwork would have needed upgrading and more digging so they opted for a small unit. The yearly cost difference was in the $10-$20 range a difference that would never be made up.


I am not advocating buying a grossly over sized unit. Was just stating my conversation that I had with more than one HVAC guy about my situation. I did have the numbers ran from the waterfurnace program and my load came up in between 3.5 and 4 tons. So going to 4 tons is not a big deal IMHO. It is not like I told the OP to get a 6 ton furnace.

I got my furnace when the HPWH's were first coming out. I didn't buy a HPHW then because I am not a fan of first generation technology. If was getting a GSHP today I would forgo the DSH and get a HPWH.

If they made a HPHW with a plastic tank, I probably would get rid of my Marathon and buy that. I plan on tying a Geyser into my system one of these days when I have some extra $$$ to throw around.

Scott


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## woodgeek

sloeffle said:


> If they made a HPHW with a plastic tank, I probably would get rid of my Marathon and buy that. I plan on tying a Geyser into my system one of these days when I have some extra $$$ to throw around.
> 
> Scott



I think you will be waiting a while on the plastic HPWH....with a low temp working fluid, you need a large area of good thermal conductivity.  I suppose they could put a coil inside the tank, rather than wrapping it around, as they do with the current all in ones.

Personally, I have not seen an external HP system with stated EF factors as high as the current (2nd gen) all in one units.  There seems to be a big skew in this board towards the externals....but they seem to have lower eff IMO.

Don't know about the geosprings, but my all in one has an active anode rod, rather than a sacrificial one, I would not be surprised if it lasted as long as a Marathon, or at least until the compressor is shot.

EDIT: geosprings have a 'heavy-duty' sacrificial anode rod that is compatible with the 10 yr tank warranty.


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## sloeffle

woodgeek said:


> Personally, I have not seen an external HP system with stated EF factors as high as the current (2nd gen) all in one units. There seems to be a big skew in this board towards the externals....but they seem to have lower eff IMO.


No to go too far off topic.

The external HP would have a dual role in my situation. It would make hot water and act as a dehumidifier in my basement. I talked to Tom in Maine about getting one and he thinks it would be over kill since I already have a DSH on my geo. Wiring it up to not run when the geo is running would be another problem.

My Marathon is only three years old so I don't think I will be getting a traditional HPWH anytime soon.



woodgeek said:


> Don't know about the geosprings, but my all in one has an active anode rod, rather than a sacrificial one, I would not be surprised if it lasted as long as a Marathon, or at least until the compressor is shot.



Can you explain the difference ? I did some quick googling and couldn't really find a definition of an active anode rod.


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## woodgeek

Sorry, 'powered anode' is the preferred term.

A sacrificial anode has an electrochemical reaction on its surface that generates a small voltage on the rod, and it is that voltage to prevents galvanic attack at the tank liner.  This reaction, however, consumes the anode slowly, like a big battery.  When it is gone the tanks rusts out. As you know, the major difference b/w a 5 year tank and 10 year tank is the size of the anode rod.  Replacing the anode regularly will often make even cheap tanks last a long time.

With a powered anode, a rod of non-reactive, non-corroding metal is suspended in the tank, and a small voltage and current is applied to it using a small external power supply, powered by grid power.  Its galvanic effect is precisely the same vis-a-vis preventing tank corrosion, but it does not get consumed, nor does it add metal ions or other gunk to your water supply.  It is permanent.

The only downside is that tank corrosion can occur during grid outages.  Also, just switching off the breaker during vacation will also lead to a couple weeks of tank corrosion.  Instead, these units have a 'vacation mode' that turns off the entire unit except the rod power supply.


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## Jerry_NJ

How is your water furnace Envision DSH set up, one tank or two?  Seems when the HP is running you may be getting enough hot water from the DSH, correct?

My question is skip the DSH and put in just a HP WH, or skip the HP WH and put in a DSH with just one 80 gallon dual element water heater with the lower element off, and maybe with a timer that shuts down the water heater all together for many hours a day/nigh when I expect to see low to no use.  I am not considering installing a dual tank system... albeit I like the dehumidification benefits of the HP WH.

I am also considering not buying the emergency heat but would still like to have a 2kw AUX heating element.


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## sloeffle

woodgeek said:


> With a powered anode, a rod of non-reactive, non-corroding metal is suspended in the tank, and a small voltage and current is applied to it using a small external power supply, powered by grid power. Its galvanic effect is precisely the same vis-a-vis preventing tank corrosion, but it does not get consumed, nor does it add metal ions or other gunk to your water supply. It is permanent.


Glad to hear that the hot water heater manufacturers have finally gotten into the 21st century. Personally, I never understood why you would build a tank that holds water out of steel. I saw my folks have two broken hot water heaters in 20 years and that sold me on the Marathon.



Jerry_NJ said:


> How is your water furnace Envision DSH set up, one tank or two? Seems when the HP is running you may be getting enough hot water from the DSH, correct?
> 
> My question is skip the DSH and put in just a HP WH, or skip the HP WH and put in a DSH with just one 80 gallon dual element water heater with the lower element off, and maybe with a timer that shuts down the water heater all together for many hours a day/nigh when I expect to see low to no use. I am not considering installing a dual tank system... albeit I like the dehumidification benefits of the HP WH.


One 50 gallon tank. Only three occupants in my house.I have it setup like the diagram in this link. As I stated before, shutting off the bottom element will result in lukewarm water. The DSH will only run when the furnace is running. If you have a mild summer like we had this year then you are not  going to make much "free hot water". The DSH stops making water when the water temp reaches 130F. Per Waterfurnace doco:

Hot Water High Limit
(Domestic Hot Water Option)
This mode occurs when the hot water input temperature is at
or above 130°F for 30 continuous seconds. The DHW limit status
LED on the unit illuminates and the hot water pump de-energizes.
Hot water pump operations resume on the next compressor cycle
or after 15 minutes of continuous compressor operation during the
current thermostat demand cycle

I think we have beat this to death enough. But I think you are money ahead forgoing the DSH and getting a HPHW.


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## Jerry_NJ

Thanks, 130 degrees is fine with me, we run the hot water heater at 125 degrees now.  I understand I'm on resistive hot water during mild weather, I don't have to see a payoff of the DSH in the first couple of years.  With the improved hook up to the new 80 gallon hot water heater I think the DSH will be a good investment.  Still, I like the year around dehumidifcation from the HP HWH. 

I sent my dealer a note via his web site asking him to price my system with model 38, 3 Ton, in place of the model 49, 4 Ton (that should shave a few bucks off) and with no emergency heat, another option I have found of almost no use in my 21 years experience.  First, I had the resistive heaters disconnected much of the time so I could turn down the heat about 5 degrees at night and not get whacked with Aux/Emer heat thrown in when I ask the HP to bring the house back up in the morning.  At least 99% of the times I needed emergency heat (recall one 5 day and one 10 day stretch) it was because electricity was out... not emergency heat, then once for a few days when the blower went out (at about year 15) well no resistive heat without a blower.  Too, I have at least 5 KW of emergency heat in portable units, and an airtight wood stove (insert).  The insert is what allowed me to stay in my home when the electricity went out, and when the blower went out.   I think these two cuts from the proposal should knock at least another $1K off the cost, really only $700 given the rebate I'll not be getting for options not purchased.  That's about enough to pay for the DSH.


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## moey

Can you use your resistive heating elements from your existing system? Depends on the size I guess. Id be hesitant not to get something in case your HP locks out for some reason while your out of town.


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## woodgeek

I was pricing out 10kW strips yesterday....$60.  And presumably the $$ wiring is already there, just kill 'em at the breaker if you don't want them to ever come on.


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## Jerry_NJ

I can ask my installer/dealer.  He agreed to use my existing loop pumps (in my current system it ran one pump for Stage I and two pumps for Stage II, dealers says that's no longer the practice.  Both pump motors were replaced about two years ago and considerable $$ by another dealer I no longer use.  But that's another story.

In any case he seems to be okay with reuse, but the subject reuse of the Aux/Emer heating strips didn't come.  I did ask about cost in the context of not installing the heating strips.  If I go for the smaller 3 Ton (or 3.5 Ton I think he calls it) the model says I need a few hours of at least 2KW aux heat at a 12 degree outside temperature.  It gets that low in NJ, but only for a few hours in the wee hours of the morning.. when I'd like to set the house temp down to 65 degrees, not the design 70 degrees.  Still, I think I recall (couldn't be more than a few times, I really don't remember when) a couple of times NJ saw zero degrees, which says the small HP would have to have aux supplements... but I can use my wood stove and portable heaters too...  HP just needs a "little" help.  

Talked today via telephone and the dealer still recommends going with the 4 Ton unit, saying that the smaller unit is only a few hundred less expensive.  And, the "design maximum balance point is 13.5 degrees" where as the 4 Ton has a "..max balance point of 0 degrees" which I think is overkill.  

Again I'm more concerned about too much cooling in the 4 Ton not too little heating in the 3/3.5 Ton.  

From the Water Furnace GeoLink Project Report it shows a lot 100% run time on the smaller unit, starting at 12 degrees, and as noted it can't handle 11 degrees if I want 70 degrees inside.  Not a big deal to me for all the above reasons, and the resistive aux will run to handle that at the cost of a few dollars a year for the NJ  weather model.  I think this is good, right, the HP: compressor, blower, and loop pumps all like running continuously more that cycling between Stage I and Stage II.

Here's a strange number in the GeoLink numbers.  It shows the smaller unit with an average COP of 3.78 seems rather low given the Stage II is rated at 4.1 and that excludes Aux (resistive) heat which is accounted for elsewhere in the report.  And, the HP runs a lot in Stage I too and that has a COP of 4.8  how can the "average COP" be so low?  To complete the picture the COP is specified at a loop temperature of 32 degrees, the Report shows the "Minimum Extreme Tempeature" at 37 degrees and the average heating loop temperature at 45 degrees.  Something just doesn't add up, that is I think the HP should be performing better than the model shows.  Similar remarks for the model run on the 4 Ton unit.  Lower average COP 3.27 with specs at 4.0 and 4.6 for 32 degree loop temperature.

I may push for the smaller unit, not sure if I want to ask about the question in the above paragraph.  There seems to be no reason Water Furnace would run a model that shows lower HP performance than they claim in the specifications.  Surely the specifications are verified by tests, at least in the design check-out and perhaps in the qualification for Energy Star ratings.


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## woodgeek

You don't want to hear it, but here is goes....

1) If the balance point were 12 degrees (at 70°F inside), you are correct that you would not need aux at 65°F overnight inside....BUT, you would not be able to recover the heat w/o aux.  It would go to 100% and take many hours to climb out from 65 to 70.  I suppose you would need the woodstove.  

2) I would worry more about the error on the 12°.  It is prob 12±5 or 12±10°F.  What if the installer is wrong, and the balance point is 22°F?  And you have no aux!  You'd be calling him back.  He is pushing the 4 ton to avoid that possibility...the dreaded callback and unhappy customer.

3) The real COP of geos in the field as measured in surveys is closer to 3-3.5, not including *any* aux calls.  The manufacturers do not include the pump energy, or might use a real low-ball estimate for pump energy.  Installers hate call-backs, so they always go for a big beefy pump that uses a ton of electricity compared to manufacturer assumptions.  Add in too small loops, or too restrictive loops, and you get cold loop temps, even more pump energy, etc.  It's sad, but you really can't trust the COP numbers from geo manufacturers.  If you want to know your COP, you need to put a sub-meter on the power in, and do some calorimetry on the BTU output.

4) The aux strips are just coils of nichrome wire like in a toaster or hairdryer.  The cost of a 2 kW or 5 kW or 10 kW are all going to be in the $50-100 range for the hardware.  A rather expensive part of your install is the heavy gauge copper running from your box to the geo/aux.... and obviously all that wiring is going to be reused.  The run cost of the aux will *not* depend on its size.  If you need XXX extra BTUs, the stat will either call the little aux for long time, or the big one for a short period, same kWh and $$.  So, just get a decent sized one for the functionality....like 5 or 8 or 10 kW, it won't cost much with the wiring in place.  And then switch the breaker off for it if you want, and rely on the wood insert.  But when you sell you have an actual normal system installed, and a decent back-up.


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## Jerry_NJ

Yes, I given up on not buying resistive heating (haven't asked about reuse, but the cost of new isn't a deal breaker).  This is a replacement of an existing unit that has dual 5KW (approx) heating strips, so the brakers are there and usable.  

Well the GeoLink program must take the other electrical loads into account, thus the smaller COP numbers in the run.  If the model is correct it show my house design load (at balance point?) is 46 KBTU for both units, guess that's why the bigger unit crosses the Load Line at a lower temperature.  In any case, the bigger unit maxes out at about 37KBTU the smaller at 28KBTU (with one 5K Resistive that goes up to about match the larger HP only), but the weather data predicts only 35 hours below 12 degrees.  Further the model predicts the small unit will use a total of 107 KWH total resistive for the year.  Thats about $15, not a problem and there is no question the smaller unit will do a better job of air conditioning, including humidity control.

So, I am again reaching the conclusion that the smaller unit is the right answer, with aux/emerg resistive included.  The installer said he can set the aux to stay off for 30 minutes when more than 2 degrees are called for at the thermostat.  I could be convinced to not turn the heat down at night, maybe just damper down the Master Bedroom ducts - still plenty of room to move air and the small unit moves less CFS too... guess the lower blower rate makes the temperature out about the same for both units.  Here I believe the best HP is one that runs a lot at low power consumption - this does a better job of cleaning the air, and of distributing temperature to all corners of the house. The model sees the smaller unit running 100% in Stage II for about 1000 hours a year. That's a little over a month of constant running.  Of course it comes in spurts with warmer outside temperatures in-between.  Still, the smaller unit will see more constant run with fewer start/stop.  Further I think the small unit can work with only one loop pump running for both Stage I and II, spec shows 8 gpm, the big unit needs 11 gpm in Stage II.

Yea  your right on the "when I sell" very unlikely the buyer will be anything like me : ) or :  ( either way I find my conservative (tight wad) thinking is well off normal.  So it would be the responsible thing for me not to Screw up the next buy who had no idea the heating system needed so much hand support.. besides, he/she will likely have to go to work too, not retired.   I used to travel a lot on business and my wife had to depend on the HP not on backup/aux arrangements. Still the small unit will work just fine needing and having only a minimal use of resistive axillary heat.   With the 5 KW resistive on the little unit is putting out about 45KBTU with a combined COP of about 2.0, not a big deal give the small number of hours this will be needed.


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## woodgeek

Let's play with some load numbers. I would interpret his numbers as follows....

Usually, they start with a 99% temp, an outdoor temp a location is above 99% of the time (all but 80 hours on average).  Sounds like your 99% temp is around 13°F (mine for comparison is 5°F).

You then compute the BTU load at the 99% temp, the 'design load' and make sure the unit can cover it.  Sounds like your design load is 46 kBTU/h.  Seems like a reasonable number (mine for comparison is 38 kBTU/h).

So, on the coldest days of the year ('design day'), the bigger unit will get 37 kBTU from the geo, and 9 kBTU (about 2.5 kW) from the aux.  The smaller unit will get 28 kBTU from the geo, 18 kBTU (about 5 kW) from the aux.  Times 24 hours, the larger unit will burn 2.5*24 = 60 kWh/day in the strip, while the smaller unit will use 2x that, 120 kWh/day.  (for comparison, during the polar vortex, I ran my 15kW strips for 9 hours, in addition to my (low output) AHSP, burning 135 kWh/day)

My guess is that when you were still working, the old unit could've called 50 kWh on scattered really cold days and you would not have noticed on the bill.

Much more important (IMO) is performance at your 'average January temp'.  Your bill will not be much affected by design day...you want to make sure than your **average** day does not use much aux. In other words, you want your balance point temp (where no aux is required) to be well below the January ave temp.  My average Jan temp (24 hour ave) is ~29°F, but it seems you are a little warmer, I'd guess yours is 31°F.  You can read it on your February electric bills, BTW.

Now for the fun part....if you need 46 kBTU at 12°F, how much do you need at 31°F?  The DeltaT (indoor outdoor) is 39° instead of 58°F, so you would need 46*(39/58) = 31 kBTU/h.  You can figure appliances and body heat and solar gain provide maybe 5 kBTU/s, so you would need 26 kBTU at 31°F.  This seems very close to the Stage II output of the smaller unit.  If this analysis is correct, the smaller unit's 'balance point' is very close to you ave Jan temps.  If this is true, I would expect up to 10-15% of seasonal BTUS to come from aux (if you didn't burn wood), or it would raise your heating bill by 30-40% if you did not burn the insert, I suppose $200-300/year.  The bigger unit has a balance point near 70°F - (37+5 kBTU* (58°F/46kBTU)) = 17°F, and you would run little aux, as previously reported.

So, the number your report suggest that your balance point for the two units is ~29°F for the smaller unit, or 17°F for the larger (and this is assuming 5 kBTUs from 'background sources to help).  With the smaller unit, I think you are looking at $200-300 a year OR a lot of insert burning (most days) for the coldest 4-6 weeks of the year.  The bigger unit....just what you have now, disconnect the strips, and fire up the insert during a few days a year, or pay the same bills you did last year.

Are you going to spend an extra $2k to get a DSH, after a bad experience with them before, and not spend enough to get a big enough compressor to cover your average January load to save a couple bucks on install??

I think you are having a 'forest-trees' problem...You are all about staging and pump usage and might be missing what the darn thing is for in the first place....space heating!

I'd go for the bigger geo myself, but it is of course your call.

Talk to your installer...I don't get this whole 'I didn't ask', why not?  Ask HIM to explain it to you to your satisfaction!  He can take 20-30 mins face to face to discuss options, expected outcomes etc.

For the record, I think you should ditch the DSH, and use the savings for a new GE geospring HPWH, the larger geo compressor, and 10 kW strips.


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## sloeffle

woodgeek said:


> If you want to know your COP, you need to put a sub-meter on the power in, and do some calorimetry on the BTU output.


We have the 049 ( 4 ton ) unit and I put an amp clamp on one side of the 220 line coming into the unit and it was pulling 11 amps. So the whole unit ( pumps, DSH, compressor ) was pulling 22 amps total. My unit has two Grundfos pumps. They call it a Geolink Flow Center.



woodgeek said:


> For the record, I think you should ditch the DSH, and use the savings for a new GE geospring HPWH, the larger geo compressor, and 10 kW strips.



woodgeek, I think you are spot on with your recommendation except for the GE HPHW.  I have had back luck with their appliances in the past. Great write up on your last two posts BTW.


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## woodgeek

Fair enough.  He could get a conventional (well insulated) electric tank (or keep the one he has now), and as two retirees their DHW usage will be so low that it will not cost much to operate. 

I still suspect upsizing the compressor will be a smaller upcharge than the DSH, and the aux savings from it would be much greater than the projected DHW savings from the DSH.  That is: a smaller geo+DSH is more expensive to buy and to operate than bigger geo+no DSH+existing elec tank.

The next owner can replace with a (more mature, cheaper) HPWH 8 years from now if he/she wants.

To the OP: if you are worried about dehumidification....don't.  If you have a variable speed blower n the air-handler, ask the installer about slowing the blower in cooling relative to heating.  At 300 cfm/ton versus the rule of thumb 400, you would get more dehumidification than you did before.


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## sloeffle

woodgeek said:


> Fair enough. He could get a conventional (well insulated) electric tank (or keep the one he has now), and as two retirees their DHW usage will be so low that it will not cost much to operate.
> I still suspect upsizing the compressor will be a smaller upcharge than the DSH, and the aux savings from it would be much greater than the projected DHW savings from the DSH. That is: a smaller geo+DSH is more expensive to buy and to operate than bigger geo+no DSH+existing elec tank.
> The next owner can replace with a (more mature, cheaper) HPWH 8 years from now if he/she wants.


Should of been more clear on my last post.

No DSH. A HPHW is the way to go. Just not the GE flavor IMO.


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## woodgeek

sloeffle said:


> Should of been more clear on my last post.
> 
> No DSH. A HPHW is the way to go. Just not the GE flavor IMO.



We think the same, but on a 5 year ownership horizon, with two retirees not using a lot of water, on a budget, and having an electric tank already (?), I could believe that the payback might not be there on an expensive, non-GE unit.  I love my giant AOSmith, but the MSRP is $2k, as much as a DSH.

The OP needs a lot of space heat, but not much DHW.  The Next Owner can upgrade the DHW if he/she wants to reap some savings.


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## Jerry_NJ

Seems my writing ability isn't up to the task.

I spoke with my dealer about the HP WH, he sells AO Smith, the price is high.  We have already decided to reusing not only my ground loop, a given, but also my GeoLink Flow Center which had it two pumps replaced about two years ago.  It pumps 6 GPM with one pump and 12 GPM with both.  The 3 Ton would have "extra" flow in Stage II as it needs only 8 GPM.  The plan is to always run both pumps, WF seems to have given up on using lower pumping rate for Stage I.  I have not spoken with my dealer on reuse of my existing aux/emerg heat.

The Geoling Project report (a Water Furnace software package, or at least not the dealers private way) clearly states the for the 3 Ton unit
Balance point 13.5 degrees and Stage II heat goes 100% at 17 degrees, with no auxiliary heat until 12 degrees.  It also states the annual heat is 99% HP 1% Resistive, at 107 KWH. It also shows the 3T unit annual cost to be over 13% lower cost, this includes heat/cool and hot water (assumes DSH).

I hope the above dispels any notion that I'd be screwing any buyer who doesn't want to use fire wood heating supplement.  The bottom line on both uits is quite affordable, and assumes a higher electric rate than I am now paying:  3Ton Totals $1,423  and 4Ton $1,549 and both hold the house to the same heating/cooling demands.  The only "ringer" that troubles my dealer about the smaller unit is the model assume an "internal heat gain" of 8,400 BTU/Hour, but even if it were zero the smaller unit appears to be able to handle heating all the way to 32 degrees, and surely most of the time below 32 degrees outside are after dark.  The model says for my area: about 1,000 hours total.  So the worse case suggests the 3Ton could use aux heat help 1,000 hours a year, at 8KBTU, 1,000 hours of 2.35KW per hour totals to 2,350 KWH at 15 cents costs $345 in a year.  Well, obviously the true "internal heat gain" is more than zero, suppose it is only have the estimate, and is 4KBTU/Hour, the the above cost goes to half and makes the total cost about the same the 4Ton for heating, and the 3T still cost less for cooling and does a better job.

Further data favoring the 3T.
Loop flow for Stage II is 8 gph, gets 12 gph  4Ton requires 11 gph, also get 12
Stage I fan 1050 cfm, Stage II fan 1250 cfm, 4Ton much noisier at 1350 cfm and 1550 cfm respectively.

One thing not clear is the Project Report shows the DSH with a variable BTU output and it remains on at or greater than 1,302 BTU/H or greater throughout the temperature range, in the case of the 3T that includes even when some light aux heat is being used.  The report also shows the DSH output as high as 3,014 BTU/H for the 3T and as high as 5,332 BTU/H with the 4 Ton, talking some serious water heating at the upper end. Strangely both units in the Report show low heating at the upper cooling load ranges, must be an assumption built in about the temperature of the water in the tank, i.e., when 97 degrees outside, the HP has been running at or near 100% and the tank is full of hot water.  At the mid range when the HP is running below 20% we see the high input heat to the Water Heater - and they are different as shown, so the DSH must also reflect the size of the HP unit, not one DSH fits all.  Thus, while the 3Ton runs a lot more the 4T produces more water.  The Report (which you all seem to doubt) shows the 3Ton HP producing 55% of my hot water and the 4Ton producing 58%.

My one assumption that keeps me pushing for the 3Ton is the belief that long run times with fewer start/stop cycles is the best operation condition when using a heat pump (or any facility that uses rotating machinery).


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## woodgeek

*For the record, if you and your installer are all agreed on what you want and what you will get, I really don't care.*



Jerry_NJ said:


> The Geoling Project report (a Water Furnace software package, or at least not the dealers private way) clearly states the for the 3 Ton unit
> Balance point 13.5 degrees and Stage II heat goes 100% at 17 degrees, with no auxiliary heat until 12 degrees.  It also states the annual heat is 99% HP 1% Resistive, at 107 KWH. It also shows the 3T unit annual cost to be over 13% lower cost, this includes heat/cool and hot water (assumes DSH).



Ok, I'm sorry but this makes no sense to me. If we think the balance point is where the geo hits 100% and the aux starts cycling, then why does the report 3 different temps for that condition....12°F, 13.5°F and 17°F?



Jerry_NJ said:


> I hope the above dispels any notion that I'd be screwing any buyer who doesn't want to use fire wood heating supplement.  The bottom line on both uits is quite affordable, and assumes a higher electric rate than I am now paying:  3Ton Totals $1,423  and 4Ton $1,549 and both hold the house to the same heating/cooling demands.  The only "ringer" that troubles my dealer about the smaller unit is the model assume an "internal heat gain" of 8,400 BTU/Hour, but even if it were zero the smaller unit appears to be able to handle heating all the way to 32 degrees, and surely most of the time below 32 degrees outside are after dark.  The model says for my area: about 1,000 hours total.  So the worse case suggests the 3Ton could use aux heat help 1,000 hours a year, at 8KBTU, 1,000 hours of 2.35KW per hour totals to 2,350 KWH at 15 cents costs $345 in a year.  Well, obviously the true "internal heat gain" is more than zero, suppose it is only have the estimate, and is 4KBTU/Hour, the the above cost goes to half and makes the total cost about the same the 4Ton for heating, and the 3T still cost less for cooling and does a better job.



Yeah.  That's quite a 'ringer'.  How does your house have a 8400 BTU/h internal gain?  Your appliances and body heat are prob 3-5 kBTU/h tops.  Maybe they are figuring on a lot of solar gain?  The after dark thing is irrelevant.  Yeah, it will keep up at reduced nighttime setpoint temps, but it won't be able to *recover* the indoor temps in the morning until a couple hours after the outdoor temp rises above 32°F, without aux or the insert.   I've lived with a balance point in that range, setbacks, and no aux for a while....it all seems aok until you try to recover.

How does the 3 ton and 4 ton both hold the house to the same heating demands (without aux), when they have very different rated BTU outputs??  

Now the balance point might be 32°F (close to my estimate), and you are paying up to $345/yr in aux.  If we split the difference, and say you have 3-5 kBTU internal gain, and a 32°F balance point for the 3 ton (without gains), then sure, it might just cost you a $100-150/yr in extra aux (in an average year) than the 4 ton.



Jerry_NJ said:


> Further data favoring the 3T.
> Loop flow for Stage II is 8 gph, gets 12 gph  4Ton requires 11 gph, also get 12
> Stage I fan 1050 cfm, Stage II fan 1250 cfm, 4Ton much noisier at 1350 cfm and 1550 cfm respectively.



I don't see where giving the geo more gph than it needs is desirable....pump power is a major source of reduced COP.  If you are going to run both pumps all the time for both units, the 4T will achieve a higher COP, by running the two pumps fewer hours.  IF you think your air is too noisy, slow the fan down if you have variable speed, the effect on COP is quite modest.



Jerry_NJ said:


> One thing not clear is the Project Report shows the DSH with a variable BTU output and it remains on at or greater than 1,302 BTU/H or greater throughout the temperature range, in the case of the 3T that includes even when some light aux heat is being used.  The report also shows the DSH output as high as 3,014 BTU/H for the 3T and as high as 5,332 BTU/H with the 4 Ton, talking some serious water heating at the upper end. Strangely both units in the Report show low heating at the upper cooling load ranges, must be an assumption built in about the temperature of the water in the tank, i.e., when 97 degrees outside, the HP has been running at or near 100% and the tank is full of hot water.  At the mid range when the HP is running below 20% we see the high input heat to the Water Heater - and they are different as shown, so the DSH must also reflect the size of the HP unit, not one DSH fits all.  Thus, while the 3Ton runs a lot more the 4T produces more water.  The Report (which you all seem to doubt) shows the 3Ton HP producing 55% of my hot water and the 4Ton producing 58%.



Just for the record, if you used 100% resistive DHW, I suspect your annual bill would be ~$300.  If a DSH is providing 50% for free, it is saving you $150/year.  You said the DSH and second tank cost $2k.  Why would you spend $2k for a system that saves you $750 over the next 5 years before you sell the place?  A geospring HPWH costs $500 after rebates, with extended warranty, and it would also save you >50% of your hot water bill, $150/year.  But its a no-go, despite paying for itself before you sell the house.

Seems you are very concerned about saving $150/yr on DHW, but not so concerned about paying an extra $150-250/yr on aux.  I don't get it.



Jerry_NJ said:


> My one assumption that keeps me pushing for the 3Ton is the belief that long run times with fewer start/stop cycles is the best operation condition when using a heat pump (or any facility that uses rotating machinery).



We're gonna disagree on this one too.  Certainly true for internal combustion engines with sliding metal-metal contacts whose oil film drains away.  But I have NEVER heard of such a think for electric motors....all low temps, roller bearings, no combustion....why would it not want to start and stop??


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## Jerry_NJ

WG, you sure like to argue, but I guess that's why I came here, to get other views.

You have not persuaded me otherwise, and ask that you at least get the correct information on what is the biggest cause of wear on electric motors, start/stop. that's one reason for the upgrade to the EMC blower, and variable speed compressors (I am buying a two speed compressor with a EMC variable speed blower) - soft start up, gradual torque build, not just slam on/off.  There is no doubt in my mind that the 3 Ton running for 24 hours straight suffers less wear than the 4 Ton going through a considerable number of cycles during the same 24 hour  period going between Stage I and II, i.e., Stage II, then stop and restart in Stage I, then stop and restate in Stage II... and so on and just for a guess it may go through 10 or 20 cycles of switching between Stage I and II while the 3 Ton is running constantly in Stage II.  The 4 Ton compressor is suffering considerable more damage. 

The blower speeds are not just a pick one, these are the speeds Water Furnace recommends for the two units.  Seems the 4 Ton moving more BTUs needs more air to do that to provide the design COP.  I suspect the Plenum heat gain for both units is about the same, the 4T moves more heat my using more air.  Both need the same temperature drop across the condenser to operate efficiently, so the 4T has to move more air.  My current three speed blower is something like 1000 cfm (manual on mode runs when HP not operating) and it is almost silent.  It runs 1200 cfm in Stage I and 1500 cfm in Stage II and is noticeable noise.  One of the things I liked about the existing Geo HP, which replace a 6 year old GE air-to-air HP, was it is SO quiet, compared to the roar of the old AS HP. If the 3 Ton can do the job and be even quieter, great ! 

As for the temperatures, the WF Program based on inputs the installer 21 years ago provided to define my home and that established the 13.5 degree balance point for the 3 Ton and 0 degrees for the 4 Ton.  I picked the other temps off of a table showing the energy uses at different temperatures, one being 12 degrees and one being 17 degrees.... the 17 degrees being the first time 100% run time is shown, 12 degrees (another data point) being the first time Aux heat is reported.  This data does not say Aux is not on for some short periods at 13.5 degrees.  It does say a 5 KWatt Aux element is on intermittently, not constantly when the temperature is 12 degrees, indeed the table shows a total of 5 hours at 2 degrees is expected and the Aux heat needed is 12 KWH, or just an average of 2.4 KWH per hour.  That 5 hours is of course when I have the house set back to 65 degrees which makes the outside temps correspond to 7 degrees not 2 degrees, and the 7 degree data point shows 30 hours expected using a total of 69 KWH, getting real close to a 2 KW (6.8 KBTU) aux supplement needed.  As I stated some somewhere in the past on this thread the Report shows the 3 Ton needs a total of 107 KWH Aux heat for the whole year.  

Again, I have 21 years experience with a 4 Ton WF Geo HP and I have run it without the Aux connected.  I have seen a lot of temps at 10 degrees when I got up in the morning and the HP was not running 100%, but it heat BTU output of my old unit is similar to that of the new 4 Ton proposed, and both have a balance point of zero degrees. And both assume a 8 KBTU "free heat" from sun, refrig, bodies, whatever and it seems that number isn't far off.

My house was built under "all electric" protocols in 1986 and has double insulation R38 or thereabouts.  Of course when I run the insert I have to let some air in but the Insert is putting out more heat than the 4 Ton HP.  I have no doubt about the 3 Ton (or 3..5 Ton - the label really applies to cooling on these units not heating).


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## woodgeek

Again, I am happy you have finalized your design and are ready to pull the trigger.  As so often happens, where a person ends up is rather different from where they start out.  I do that myself.  

It seems that you started out being very satisfied with your previous 4 ton unit, comfortable, affordable, green.  Does not need aux regularly, etc.  That lasted for 20 years (and of course the loop is still aok).

Your first question to the board earlier in the year was whether if you downsized to 3 tons, would you use a lot of aux, b/c you wouldn't want that.  You didn't have a lot of hard data to go on, but is sounded like yes, you would.  Maybe a couple hundred bucks worth per year, not the end of the world, but there it was.  You have a report full of numbers in front of you, that we can't see, and keep quoting numbers from it that do not appear to be mutually consistent.  Most of the numbers you have quoted make it sound like your balance point on the 3 ton is going to be somewhere in the 20s, rather than somewhere in the single digits or low teens, like the old unit.  Based on the BTU numbers you quoted, that is just the sort of difference in balance point one would expect from downsizing that much, and that we estimated earlier in the year.

But its cool, we still just think the smaller unit is going to cost a couple hundred dollars a year in extra aux.  The only thing that has changed is how much you care about that much aux, now not very much.  I think that is reasonable....maybe you were worried it would be really expensive, and when the pro projections come in a couple hundred dollars, it matters not.

Now you tell us that you are more worried about summer dehumidification, operating noise and avoiding start/stops (despite the previous 4 ton somehow being ok for 20 years), so you are going for the 3 or 3.5 ton.  Ok. Done.

The second question was whether you should get another DSH.  You said that you were never really satisfied with the one you got before, AND that you two needed very little hot water.  We pointed out that for the same money you could get a v nice HPWH that will be more efficient, simpler and more compact (than two tanks) and work better than a 1 tank DSH system.  Or for less money you could get a cheaper HPWH (that will likely last the 5 years you are in the house).  Or for even less money, you could just run with the existing elec tank and no DSH, and the upcharge on your annual bill might be $100-150/year.

You heard all that, and then decided that you are getting a new DSH.  I assume that some unknown reason came up that made the DSH more attractive.  Ok, Got it.  Done.

I DO like to argue, but *we* aren't arguing.  You asked if a smaller geo would call more aux, and how much it would cost.  The answer is yes, and the amount is prob a couple hundred bucks a year.  You asked if there were better options than the DSH, that might be cheaper, more efficient, or both.  Again the answer is yes, you could save $1k on install and get a more eff DHW system, or save $2k and have a system that costs $150 a year more.

You asked a couple questions to the board, got some answers, and then you and your pro installer discussed all the details and decided to get the smaller geo and DSH.  Sounds like your installer did a good job of walking you through the decision process (something we can't do), allayed some initial concerns you had (as expressed here), gave you some various operating cost and install cost estimates that were acceptable to you, and you picked what you wanted.


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## Jerry_NJ

Thanks, suppose we've ran this on to the ground, or into the ground, geo : )  

Side point, most of the responses I got earlier, not lately, on the same set of issues posted on the GeoExchange Forum, populated by more than a few "sellers", was I should consider going smaller than the 3/3.5 Ton.  So I had that advice in my mind in all of our discussions.  

Yes, I have proof that it is possible for a two stage compressor of the 1990s design (not a scroll) holds up well to what must be thousands of starts and stops.  Right now it is heating and even some afternoons in the past week done some cooling and the compressor has a smooth humming sound which I hear only if in the basement... and an almost pleasant machine sound.  That's one reason I went back to Water Furnace.   As you come to know me, you may anticipate that my life with Water Furnace was not without complaint, but never against the installer or the general good performance and economics of the unit.  My problems with WF came only  after 15 years when I needed repair, my dealer had retired and I didn't pick the best replacement, and the poor job WF on parts supply, because my unit was so old.  I understand they are an OEM and all of the rotating machinery they have thy buy on contract from a supplier/mfg who decides when to stop manufacturing an item, the case now even for the compressor in my existing unit. So, yes I like my existing unit and if I could replace the existing compressor (better if with a retro Scroll) for under $3K I'd do it.  I have replaced the pumps and blower, the DSH pump is out but didn't plan to repair for the reasons you understand better than me, so a new compressor would have put my unit in the reliable column for another 10 years at least...yes there are connection and the condensor ... plus other relay stuff, plus electronic that are old. But absent a new compressor a complete replacement leaves a more comfortable feeling. 

I post her seldom in recent times, but I came to The Hearth for wood heating exchanges and information and had no reason to visit here in the "Green Room" other than a few times as I don't consider wood heat "green" but do consider my Geo unit of 21 years to be an effort in the green direction and sound economically.  I know I have saved at least $1,000 maybe $2,000 a year in the last five or more years over what it would have cost me to heat with oil.  Yes, I've burned a couple of cords of wood, much paid for with sweat labor as I have over 5 acres - another green contribution I make. But before the Geo unit, when I had only an air-to-air unit I burned a couple of tons of anthracite coal in a coal stove in the basement.  That looked clean, not much visible smoke, but we all now it was not and neither is my wood even though I installed a modern approved air tight insert in my fireplace a few years back - listed in my "signature".

As for the numbers I have in the study, I'm at least okay with numbers I have a masters in electrical engineering and about 40 years as an engineer and engineering manager.  That helps me think logically, it doesn't make me a great typist (typos do plague my typing) or even necessarily as careful at with the content of my post/reply here, but I do nonetheless get usefull information, and some incorrect information.  But even my medical doctors advice is subject to me making self-interest decisions on what I do next.

Thanks for working with me on this exploration on sizing a HP.  On Hot Water generation, the decision is still very uncertain and if I go DSH i'll report my results here, results that will disclose numbers and methods of obtaining those numbers. But number absent any specifics on how much in electricity, rather how well the DSH heats water given my DSH/HWH management methods, e.g.,, use of timers and the like.


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## woodgeek

Something that I like about your process is that you are giving a thought to the next owner....

The next owner will either be like 95% of homeowners, and will happily pay the elec bill every month and never give a thought to the HVAC or DHW until it quits, or if a member of the other 5% (perhaps an engineer like us) and he/she wants to save money or energy, they will develop a plan to do so.

I think the most cost-effective way to save energy in your existing house would be a energy retrofit, which could likely drop your heating and cooling loads by 20-30%.  A house of the 1986 vintage would be a prime candidate for such a retrofit these days....which would mostly be airsealing and ventilation work.  After retrofit a 4T unit will be way oversized, and 3/3.5T will prob never need to call any aux.

I am NOT suggesting you undertake a retrofit project...IMO with cheap geo BTU and a 5 year horizon doesn't make sense.  

So, from the next owners perspective, they either don't care (95%), or they will be happy with the 3T (5%).


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## sesmith

I'm a little late to this discussion, but I'll throw in my 2 cents, having lived with a climatemaster 3 ton system with DSH for the last 3 years and occasionally (rarely) using my wood stove.

You definitely want the DSH set up with it's own dedicated tank to be most efficient.  FWIW, our DSH does almost all our water heating when our geo system is running steadily in the winter and almost none of our water heating in the summer.  The average over the year works for us.  A HP water heater may work best for you, especially if you could use the cool air it produces, and if its noise isn't an issue for you.

Ideally, to be most efficient, a geo system should be designed to use second stage, and even some aux heat during the winter.  Even when aux heat is running, the system is still producing most of it's heat from second stage operation.  It doesn't just switch to a COP=1.  I measured my system's COP a couple of years ago at various times throughout the season.  What I found was that in second stage, the system was basically as efficient as when it was in first stage (right around 4).  When  aux came on, it was still running with a COP of 1.87.  AUX was only running for around 15 minutes of every hour as a supplement, so the system was still very efficient on an hourly basis.  So I never worry when I see second stage on, and if I want to use my basically free aux from the wood pile (now  getting very old in my yard), I'll fire up the wood stove on the nights it's below zero out.  
One thing we experimented with, and do not do, is any setbacks, even though we like it cooler when we sleep.  Our system just has to work too hard to bring the house temp back up in the dead of winter.  There's just a lot of mass in my old house, and it seems to work better to keep the house at one temp.  We opt to just close the heat ducts off in our bedroom and close the door when we're sleepi

You may want to post some of your questions to the geo forum as there are several knowledgeable installers that frequent it.

http://www.geoexchange.org/forum/


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## Jerry_NJ

Thanks, I have written the check paying 1/3rd of the contact cost and placed it in the envelope with the signed contract, didn't mail yet as the Government shuts down on Columbus day, nothing else does...go figure.  I discovered it is Columbus day when I drove to the NJ auto inspection station and found it closed. 

I have decided to go with the so called 4 ton unit, a close match to what I now have.  The new 049 two speed Series 5 has a maximum (32 degree loop) Stage II heat of 37KBTU, my current is rated at 33 KBTU.  I was told I can have the delay switching to Stage III heat  (5 KW Aux) to be 30 minutes, which I plan to do. I also plan to have the fan manual operation to run at the Stage I level of about 1300 cfm to help move wood heat when the HP isn't running.   My current manual fan speed is 1000 cfm.  This is one way to cool the upstairs down, as the HP thermostat is in the living room and the wood insert will raise the temperature there above the 70 degree set temperature... the upstairs will drop to 65 or so even with the fan running to circulate air around the house. 

Thanks for the good testimony on the DSH for hot water I have decided to include that unit and I plan to get by with a new 80 gallon AO Smith electric water heater with the lower element set at the lowest possible temperature, about 90 degrees I think it is.  I also plan to simply shut the hot water heat off when the heat pump is running a lot, heating or cooling.  The 4 ton DSH is rated at over 5KBTU input to the hot water when the water is cool (don't have the temperature, but suppose that sort of heat transfer occurs only when the tank being heated is closer to cold water temperature, say 55 degrees or so.  I'll at least have a timer cut off to the hot water heating elements to shut down around 6 PM and not come back on before about 7 AM, or over half the 24 hour cycle.  I believe these strategies will help the one tank system perform near that of a two tank system. 

While I still like the idea of the smaller unit running a lot, even 100% with an outside temp in the lower teens, and using some Aux periods to supplement when the temp drops toward zero, that's unusually cold for NJ.  A 10 degree morning was seen a few times last winter, but no zero readings.

I'm a 21 year veteran of Geothermal HP and know it has paid off even given the high initial cost, was about $12K including the ground loop back in 1993.  The price has at least doubled in those 21 years, but the cost of heating oil as gone up over 300% in the same time while electricity has gone up less than 50% - I've saved at least a couple of thousand $$ a year in each of the last 6+ years.  The cost benefit was about a wash with oil heat when I installed the existing system, and oil was under $1 a gallon, electricity about 10 Cents KWH.  My electric provided provided about $3K incentive, making my cost about $9K in 1993. 

But I still have to remind myself of how economical the HP is when running - my automatic reaction is to react negatively when I am aware (like when in the basement) the HP is running with concern about the cost.  I had natural gas heat in the home before my current, and it then and now is very competitive and if I could have I'd have installed it here - I still like the 100KBTU heat with a register putting out hot not warm air.  Yes, the warm air is more gentle and less drying. The house before last even had natural gas powered cooling - figure that one, guess it used gas heat to develop  refrigerant high pressure, exhausting the heat into the outside air, and expanding the refrigerant to develop cooling...whatever it worked.  That was Ohio and we saw one winter with a period of temperatures at 25 and more below zero, colder even than the temperatures I experienced in Denver Colorado. Boy that gas heat was nice, and ran a lot I'm sure - must have cost as much as $40 for heating and cooking that month.  Well that was in the late 1970s, but even then $40 was affordable.   I know some folks who had electric heat, and one who had an air-to-air heat pump.  I think some of them saw $200 in electric bills.   What was electricity then?  maybe 4 cents a KWH.  Sorry for the ramble, just remembering what affects my thinking and decision making. 

I don't visit this forum often, but will come back after I gain this winter's experience to see if I can add any facts.


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## woodgeek

Or you could skip the desuperheater, use the existing conventional elec tank for your minimal DHW needs, and use the money you save to take the wife on a mediterranean cruise.


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## Jerry_NJ

She's already been to the French Riviera (Nice) and other places in France.  Nice and The Bay of Angels looks a good bit like the picture you sent.  





Unfortunately we find in our advanced years we don't feel up to such vigorous travel any more.   It takes some effort just to fly to Florida and California, two places we have family to visit as well as enjoy the warmer winter weather.  But with the new HP we may enjoy just keeping the house a couple of degrees warmer : ).  

I was engaged in international business for about 20 years when I was still young enough to know enough to be employed.   Growing old a'int for sissies.


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## Jerry_NJ

I'll try to share my experience with others in more current threads, but to conclude this thread:  THE DEED IS DONE.

My 4 ton Water Furnace (replacement) was installed, it will be one week old tomorrow.  Love it.  The smart thermostat has many features only an engineer will appreciate (no engineering degree required).

I purchased the DeSuperHeater (DSH) and so far I am happy with that decision.  The DSH in the original 21 YO Waterfurnace never really produced hot water.

As part of the installation I had a new 80 gallon electric water heater installed to replace my 12 Yo (est) 50 gallon heater - so we're all new on this subject.  I heated the water in the HW heater with the resistive elements because it was installed one week ago, a day ahead of the installation of the new WF.  Then on Tuesday last when the HP was on line I threw the circuit breaker feed to the water heater.  The weather since then has been mild and I'll estimate the HP run time at about 25 % of the time, more than half of that during sleeping hours, several days did not need any heating after 10 am.   Even with this low heating we have had sufficient hot water (two seniors, and we are young enough to take baths) with the HW heater power off.  We wash dishes in the morning when the hot water is around 125 degrees.  The dish washer is about 4 years old so it is a low hot water user, an energy star rated dishwasher, still it uses hot water, as does general clean-up around the house, cooking, baths, and some cloths washing, still enough hot water is delivered from just the HP.  

We are expecting colder weather later this week, low about 30 degrees and highs in the 40s, so the HP will be running more like 30% of the time, maybe 35%, and I feel safe expecting more than enough hot water - and I estimate we will not need to use the hot water heater to heat hot water before next April.

So whatever the poor performance of the DSH approach has been, it looks like Water Furnace has addressed that and now have a real HP generated hot water source.   Remember too, the HP has a COP of 4 or better, so my hot water is coming at 1/4th the cost of heating with resistive elements.  I recall (approximate recollection) that the dedicated water tank heat pumps deliver a COP closer to 2 than to 4.  But, the dedicated water tank HP does have the benefit of doing some welcome air cooling in the hot weather, but then so does the WF HP, with the cooling and hot water coming from a unit delivering a EER in the 20s.


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