# Advancements in cold climate heat pump efficiency.



## Brian26 (Dec 23, 2020)

Mini splits are starting to achieve some incredible efficiencies in some pretty extreme cold. This new LG unit can maintain a COP of 2.88 at 5 degrees at full output. It can turn down to a crazy low 561 btus using only 60 watts even at 5 degrees with a COP of 2.74.

The 47 degrees specs are just as impressive. It can output almost double its rated capacity with 20,472 btus with a COP of 4.55.

I went through the engineering manual and even at -13 it still has an impressive COP of 2.56 and still has close to 90 percent of its capacity.

So this LG unit will have an effective efficiency of 288% at 5 degrees and 455% at 47 degrees.










						ASHP
					






					ashp.neep.org


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## CaptSpiff (Dec 23, 2020)

Is that a 9000 btu unit ? That's amazing.


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## DBoon (Dec 23, 2020)

My recollection is that my Fujitsu RLS2H (capability of providing heat down to -17 degrees F) has comparable performance. I recall that the rated capacity for my 15 kBTU unit is around -5 degrees F. Having operated it as a primary heater in a house during renovation, I can tell you that it produces a nice, warm heat below 0 degrees F.


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## Highbeam (Dec 24, 2020)

I believe the new advancement is that it makes full rated output at -5 AND does so with a COP of nearly 3.


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## peakbagger (Dec 24, 2020)

I agree, normally the COP and output drops significantly as the temps drop. Many companies did not routinely supply low temp performance and it caused some issues with various state incentive programs in northern New England. There is non profit linked to Vermonts program that lists the preformance at lower temps a bit more typical of the region. They have a website but I cant find it right now.


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## Brian26 (Dec 24, 2020)

CaptSpiff said:


> Is that a 9000 btu unit ? That's amazing.



It is listed as a 9k unit.  Most mini splits share the same compressor and its the software that limits the output. If you look at the submittal sheets usually  the 9 and 12k and 18 and 24k units have the same compressors.


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## Brian26 (Dec 24, 2020)

peakbagger said:


> I agree, normally the COP and output drops significantly as the temps drop. Many companies did not routinely supply low temp performance and it caused some issues with various state incentive programs in northern New England. There is non profit linked to Vermonts program that lists the preformance at lower temps a bit more typical of the region. They have a website but I cant find it right now.



Its the Northeast Energy Efficiency Partners directory.  The current AHRI testing only requires performance specifications at 47 and 17 degrees.  This directory got the manufacturers to submit the data for performance at colder New England temperatures such as 5 degrees. 





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						ASHP
					






					ashp.neep.org


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## Brian26 (Dec 24, 2020)

Highbeam said:


> I believe the new advancement is that it makes full rated output at -5 AND does so with a COP of nearly 3.



Just as important are the turn down ratios between the minimum and maximum output.  That LG at 47 degrees can modulate from 1000 to 20000 btus. No fossil fuel source of heat has anywhere near that kind of variable range of btu output.


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## peakbagger (Dec 24, 2020)

Since I am up in an area where cold weather temps can go below even the 5 degree temps I have thought of getting a functioning used one and removing the outdoor coil and replacing it with a water to refrigerant heat exchanger and try a small scale geothermal setup. Ground water temp is consistently in the low forties and my guess is the minisplit compressors performance is better than a typical geothermal. Whenever I run into geothermal reps at trade shows its obvious that they are focused on whole house high end custom systems or lower efficiency units for middle atlantic and down south. 

I have participated in a couple manufacturer webinars of late and across the board they still recommend having a alternative source of backup heat from the middle atlantic north.


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## Brian26 (Dec 24, 2020)

peakbagger said:


> Since I am up in an area where cold weather temps can go below even the 5 degree temps I have thought of getting a functioning used one and removing the outdoor coil and replacing it with a water to refrigerant heat exchanger and try a small scale geothermal setup. Ground water temp is consistently in the low forties and my guess is the minisplit compressors performance is better than a typical geothermal. Whenever I run into geothermal reps at trade shows its obvious that they are focused on whole house high end custom systems or lower efficiency units for middle atlantic and down south.
> 
> I have participated in a couple manufacturer webinars of late and across the board they still recommend having a alternative source of backup heat from the middle atlantic north.



LG has an air to water heat pump now that I think is available here. It uses a new more efficient compressor and the new r32 refrigerant that is going to replace r410a. It is an all in one unit and only water lines need to be run to it.  The specs claim it can provide 149 degree water temperatures all the way down to-13.



LG THERMA V R32 Monobloc is an all-in-one unit equipped with an innovative and eco-friendly R1 compressor and R32 refrigerant. This unit can operate at extremely cold weather like -25℃ and heat water up to 65℃.









						Monobloc AWHP | Products | Air Solution | Business | LG Global
					

LG's Monobloc utilises heat generated by the outdoor unit via heat exchange with external air transferred to the domestic hot water tank. Learn more now.




					www.lg.com


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## peakbagger (Dec 24, 2020)

That is good to know if they are importing them. If you look at John Siegenthalers stuff he is major advocate of low temperature radiant emitters supplied from a thermal storage tank heated by an air to water heat exchanger with a wood or pellet boiler for backup. To date the offerings for these have been pretty slim less known companies.

I took a quick look and do not see any for sale in the US


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## Highbeam (Dec 24, 2020)

Brian26 said:


> LG has an air to water heat pump now that I think is available here. It uses a new more efficient compressor and the new r32 refrigerant that is going to replace r410a. It is an all in one unit and only water lines need to be run to it.  The specs claim it can provide 149 degree water temperatures all the way down to-13.
> View attachment 270231
> 
> 
> ...



This is what we need. Okay, what I want.


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## peakbagger (Dec 24, 2020)

Similar to several other firms, they just dont seem to want to import them in the US. 

Several companies sell inverter based refrigerators in Mexico but not in the US.


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## DBoon (Dec 24, 2020)

Highbeam said:


> I believe the new advancement is that it makes full rated output at -5 AND does so with a COP of nearly 3.


Agreed that a  COP of nearly 3.0 at 5 degrees F is a pretty nice advancement in a broader-market (lower-priced) unit.

I reminded myself what my nearly 10-year old technology Fujitsu unit could do. Take a look at the RLS2H Design Technical Manual (link here https://manualzz.com/doc/7776927/rls2h-design-technical-manual, extracted image attached). At an outdoor temperature of -17 degrees F the input power is 2.28 kW and the output is 15.4 kBTU/hr (4.51 kW/hr) or a COP of ~2.0 with indoor temperature at 65 degrees F. At -5 deg F, COP is 2.17 and at 5 deg F COP is 2.37. I could expect some de-rating from this (it is a Total Capacity, not actual Output/Hr rating, so there must be some defrost cycle lost). But still, this was a pretty good COP for its day (nearly 10 year old technology). 

Where these units historically suffered was that their COPs at higher temperatures weren't nearly as good (COP of this one only 3.25 at 47 degrees F). as units that don't have the cold-heating capability. 

I recently installed Mitsubishi MXZ-2C20NAHZ2 splits in a condo. See attached datasheet. That unit at 5 degrees F  outputs 22 kBTU/hr (6.44 kW/hr) with an input of 1.45 kW (COP = 4.44) and COP of 5.85. It can't modulate as low as the LG unit (only to about 25% of full output). I can't remember if this is capable of operating below 5 degrees F, but it is not so critical for it to do so in that southeastern NY climate. 

So it is good to know that other manufacturers are gaining capabilities for great COP at low temps. Fujitsu and Mitsubishi need some competition in that area. Their prices have been a little ridiculous (Mitsubishi more so than Fujitsu). Maybe that is why the Mitsu unit came in a lot lower than expected when I asked for a quote a year and a half ago.


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## begreen (Dec 24, 2020)

That Fujitsu is a remarkable unit. I can't forget when several years ago I visited a local old farmhouse that had one sitting next to the entry steps. It was running, but very quiet. When the owner opened the door, the heat blasted out, even though it was 14º outside. I asked if they also had a woodstove going and they said no, just the mini.


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## Brian26 (Dec 25, 2020)

begreen said:


> That Fujitsu is a remarkable unit. I can't forget when several years ago I visited a local old farmhouse that had one sitting next to the entry steps. It was running, but very quiet. When the owner opened the door, the heat blasted out, even though it was 14º outside. I asked if they also had a woodstove going and they said no, just the mini.



The Japanese invented mini splits and they had to be reliable, quiet, and energy efficient as electricity was and still is expensive in Japan. If installed correctly the refrigerant loop is airsealed and the compressor oil is never exposed to outside contaminates. The compressors can last for decades. I know of someone with a 15 year old Mitsubishi split that has been running pretty much nonstop for 15 years. Inverter driven compressor also have the huge advantage of soft starting at low rpms and gradually ramping up.

Despite what people think of the electronics  on these they are extremely reliable. These units were designed to be used mainly in Asia and China were the power can be dirty. My Chinese Gree mini split said right in the brochure it has stable operation under a wide voltage range.

Also interesting is the reason for the flare fittings on the refrigerant lines was due to the huge fire hazard in Asia. There are a lot of poorly built extremely flammable wood structures there. Here in the states brazing refrigerant lines with a flame is common practice.


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## Brian26 (Dec 25, 2020)

I have electricity monitors on both my mini split's. Its amazing to see them operate and how little power they use. I have seen them ramp up responding to me opening a door to go outside or a cold front coming through. They will lock on the temperature set point with extreme precision and modulate to the exact heating load.

Here is a snapshot yesterday of my downstairs Midea 12k spilt that carries most of my heating load. Those brief electrical spikes at the end of the graph are designed into the software for oil control. When the compressors are near their minimum speed they briefly ramp up to send oil to the compressor.


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## Corey (Dec 25, 2020)

Interesting numbers.  Curious how the 'defrost cycle' plays into those - is it already included with the rated COP?  Maybe they've found some way to get rid of it?  

 I recall that was the slightly unsettling thing about one house I was in, which was primarily heated with a heat pump system (besides the constant draft of barely warm air).   The heat pump would run with some nominal efficiency...maybe COP of 2.0 back in those days.  But every so often, it would 'defrost' the outdoor coils, so basically switch back into 'air conditioner' mode, kick on the electric resistance heat and pump that hard won heat from the house right back outdoors.   So while it could run efficiently, it seemed some amount of time was in 'anti-efficient' mode, pumping heat the wrong way.


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## Brian26 (Dec 25, 2020)

Corey said:


> Interesting numbers.  Curious how the 'defrost cycle' plays into those - is it already included with the rated COP?  Maybe they've found some way to get rid of it?
> 
> I recall that was the slightly unsettling thing about one house I was in, which was primarily heated with a heat pump system (besides the constant draft of barely warm air).   The heat pump would run with some nominal efficiency...maybe COP of 2.0 back in those days.  But every so often, it would 'defrost' the outdoor coils, so basically switch back into 'air conditioner' mode, kick on the electric resistance heat and pump that hard won heat from the house right back outdoors.   So while it could run efficiently, it seemed some amount of time was in 'anti-efficient' mode, pumping heat the wrong way.



Traditional heat pumps used a wasteful timer for the defrost.  Mini splits use software driven algorithms for the defrost cycle. They can detect the coil icing up based off the amp draw on the variable speed outdoor DC condenser fan.  As the outdoor coil ices up they can see the the airflow dropping by an increase in the outdoor fan speed amp draw. I can see my outdoor condenser through my window and the defrost controls are extremely energy efficient.


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## DBoon (Dec 25, 2020)

Corey said:


> which was primarily heated with a heat pump system (besides the constant draft of barely warm air).


The classic "heat pump" is a pile of garbage. I was happy to replace mine at the condo with two mini-splits. The old heat pump seemed to spend half its time in electric resistance mode anytime the temperature was close to freezing or if you nudged the thermostat up a half degree. It was really an electric resistance heater, in my opinion, that also provided air-conditioning in the summer.


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## mcdougy (Dec 25, 2020)

These mini splits are starting to gain nterest here in Ontario. The old school heat pump disasters caused a slow climb for them to catch on....I have a project coming up and the current shop house has in floor heat. The client has indicated that they are not interested in trying to tie into the existing system, nor interested  in doing infloor at all.  There is no basement or a/c. This points directly at a mini split in my opinion. Since I have no experience at all with a mini split I have a couple questions.....
I understand that you can have one outdoor unit and multiple thru the wall units supplied by the lone outdoor unit......Does each bedroom need its own thru the wall unit to supply a comfortable bedroom?
This shop house is currently a 1 bedroom 1 bath and largish open kitchen/family room. Currently is 1000sqft total. Built by me in 2009, well insulated and airsealed. The addition they are wanting is 2 more bedrooms and another bathroom, as well as enlarging the main space for a total addition size of approx. 600sqft. Bringing  the totals to 3 bedroom.,2 bath and sq footage of 1600. 
I have a great hvac contractor that I have worked with for over 18years, but I'm thinking he does not have alot of real experience with mini splits. He did indicate that he can get LG units. There appears to be many here with first hand experience and others with large knowledge of these systems.....What do you folks think would suit this retrofit scenario??  Since there is a lack of a/c in the current building and they are requesting a/c, I believe they will be fine with abandoning the current l.p.boiler radiant heat system. Its a white Roger's combo tank that they would still use for d.h.w..


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## Brian26 (Dec 26, 2020)

mcdougy said:


> These mini splits are starting to gain nterest here in Ontario. The old school heat pump disasters caused a slow climb for them to catch on....I have a project coming up and the current shop house has in floor heat. The client has indicated that they are not interested in trying to tie into the existing system, nor interested  in doing infloor at all.  There is no basement or a/c. This points directly at a mini split in my opinion. Since I have no experience at all with a mini split I have a couple questions.....
> I understand that you can have one outdoor unit and multiple thru the wall units supplied by the lone outdoor unit......Does each bedroom need its own thru the wall unit to supply a comfortable bedroom?
> This shop house is currently a 1 bedroom 1 bath and largish open kitchen/family room. Currently is 1000sqft total. Built by me in 2009, well insulated and airsealed. The addition they are wanting is 2 more bedrooms and another bathroom, as well as enlarging the main space for a total addition size of approx. 600sqft. Bringing  the totals to 3 bedroom.,2 bath and sq footage of 1600.
> I have a great hvac contractor that I have worked with for over 18years, but I'm thinking he does not have alot of real experience with mini splits. He did indicate that he can get LG units. There appears to be many here with first hand experience and others with large knowledge of these systems.....What do you folks think would suit this retrofit scenario??  Since there is a lack of a/c in the current building and they are requesting a/c, I believe they will be fine with abandoning the current l.p.boiler radiant heat system. Its a white Roger's combo tank that they would still use for d.h.w..



The multi split units that have one outdoor condenser with multiple indoor heads  usually have a big flaw.  The minimum heating or cooling output is often way too much and they short cycle which kills the efficiency

An example would be a 36k btu Mitsubishi that can be connected to 3 indoor 12k heads. The minimum heat output might be 9k btus. With a 1 to 1 unit you get much better turn down ratios such as the LG that can turn down to just 500 btus.


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## mcdougy (Dec 26, 2020)

Brian26 said:


> The multi split units that have one outdoor condenser with multiple indoor heads  usually have a big flaw.  The minimum heating or cooling output is often way too much and they short cycle which kills the efficiency
> 
> An example would be a 36k btu Mitsubishi that can be connected to 3 indoor 12k heads. The minimum heat output might be 9k btus. With a 1 to 1 unit you get much better turn down ratios such as the LG that can turn down to just 500 btus.


Ok, this is the type of info I am looking for. So for a all in one units.....how many do you think a place of their size need?   Do bedrooms suffer if you don't have one unit per room?


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## stoveliker (Dec 26, 2020)

mcdougy said:


> Ok, this is the type of info I am looking for. So for a all in one units.....how many do you think a place of their size need?   Do bedrooms suffer if you don't have one unit per room?



You would have to do the calculation of buying multiple (at $2000 each?)  outdoor units versus the power savings over the (20?) years as compared to one outdoor unit and multiple indoor ones.


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## JRP3 (Dec 26, 2020)

peakbagger said:


> Similar to several other firms, they just dont seem to want to import them in the US.
> 
> Several companies sell inverter based refrigerators in Mexico but not in the US.


I don't know much about them but this company sells an air to liquid unit.   https://www.chiltrix.com/chiller-technology.html
Rather pricey as I remember, I think $4k just for the outdoor unit.


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## Brian26 (Dec 26, 2020)

JRP3 said:


> I don't know much about them but this company sells an air to liquid unit.   https://www.chiltrix.com/chiller-technology.html
> Rather pricey as I remember, I think $4k just for the outdoor unit.



I think this is where the technology is heading. Here in New England most homes have baseboard hot water heat or radiators. The fact that the unit is self contained and you just need to run water lines would make installations quick and easy.


I


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## Highbeam (Dec 26, 2020)

If you can heat your whole house comfortably with a single woodstove in one room then I see no reason to think that a single indoor condenser wouldn’t heat the home at least as well from that same room. 

I live in a heating only climate and see no reason for putting in any more of those ugly wall units than I must.


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## UpStateNY (Jan 27, 2021)

This is a great thread for the Wood Pellet forum folks to read.    To save on cost of heating, I pretty much stop using my 2008 Harman pellet stove.   On that note are there any fuel comparisons web applicatons like this one that include the cost of BTU for these high efficient mini-split ductless compressors?  If someone created that I think you would see a lot more people stop using the wood pellet stoves at $6.00 a bag of quality pellets.  






						Compare Fuel Costs
					






					www.pelletheat.org


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## peakbagger (Jan 27, 2021)

It not a simple chart, The heating efficiency of a minisplit varies with outdoor temperature. As the temps drop, the minisplit eventually  turns into a electric heater.


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## Brian26 (Jan 27, 2021)

peakbagger said:


> It not a simple chart, The heating efficiency of a minisplit varies with outdoor temperature. As the temps drop, the minisplit eventually  turns into a electric heater.




Its actually pretty easy to get a rough comparison using the NEEP cold climate heat pump site I linked earlier. That has the COP numbers at various temperatures at max speed.

You can convert the COP to electric efficiency in that fuel cost calculator easily. Just remove the decimal point and enter the percentage value in the calculator for electric heat efficiency. Example a COP of 2.88 is 288% efficiency for electric heat.

Using the LG I linked in the first post that has a COP of 2.88 at 5 degrees and COP of 4.55 at 47. Here is what it would cost per million btu compared to pellets. I left the .12 kwh in the calculator that is probably the national average and left the default $245 a ton for pellets.

Pellet cost per million ton at $245 ton. 
$19.15

Mini split at 47 degrees with a COP of 4.55
$7.73

At 5 degrees with a COP of 2.88.
$12.21

An important thing with the listed COP's number is that is when the unit is running at max compressor speed. When inverters are running at partial load the efficiency significantly increases. I have seen some Mitsubishi numbers where COP's are in the double digits like 11 or 12 at low speed st 47 degrees.  At those efficiencies your looking at like $4 per million btu.


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## peakbagger (Jan 28, 2021)

So to satisfy the posters  request,  make up a simple chart that covers a range of COPs, compressor speeds  for a range of  manufacturers models that compares a range of pellet stoves efficiencies at various fuel and electric prices with local climate conditions factored in.  IMO, an Excel model with a lot of look up tables is going to be needed.


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## Brian26 (Jan 28, 2021)

peakbagger said:


> So to satisfy the posters  request,  make up a simple chart that covers a range of COPs, compressor speeds  for a range of  manufacturers models that compares a range of pellet stoves efficiencies at various fuel and electric prices with local climate conditions factored in.  IMO, an Excel model with a lot of look up tables is going to be needed.



No need to do all that work. An easier method is to use the HSPF rating (Heating Season Performance Factor). HSPF is defined as the ratio of heat output over the heating season to electricity used.  The HSPF number is divided by 3412 to get a seasonal COP. 3412 is the amount of btus per kw of electric  resistance heat.

Let's take the popular Mitsubishi MSZ-FH12NA with a HSPF of 12.5/3412 is a seasonal COP of 3.6

Cost for a million BTUs would be $10.55

Here is my Gree Sapphire 12k with a HSPF of 15. Seasonal COP of 4.4

$7.99 per million btu .

Even a mini split running at a COP of 2 is cheaper than wood pellets at $19.15 per million btu.


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## peakbagger (Jan 28, 2021)

I still dont see a chart


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## Highbeam (Jan 29, 2021)

I don’t need a chart to get the very valid point that even at 5 degrees, the mini split is beating the snot out of pellets at cost per btu. 

I just wish they didn’t look so silly!


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## UpStateNY (Feb 3, 2021)

I had my HVAC buddy install whole house ductless mini-split compressors for heating and AC for $14,000 here in Hudson Valley  in Woodstock, NY .  I got a rebate check from Central Hudson Power company for $7660.00 .    
https://www.cenhud.com/my-energy/sa...l-incentives/air-source-heat-pump-incentives/


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## begreen (Feb 3, 2021)

UpStateNY said:


> I had my HVAC buddy install whole house ductless mini-split compressors for heating and AC for $14,000 here in Hudson Valley  in Woodstock, NY .  I got a rebate check from Central Hudson Power company for $7660.00 .
> https://www.cenhud.com/my-energy/sa...l-incentives/air-source-heat-pump-incentives/


What system did you have installed? Does it have resistance coil heat for backup? If yes, what is the crossover temp to the resistance heat coils?


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## UpStateNY (Feb 4, 2021)

begreen said:


> What system did you have installed? Does it have resistance coil heat for backup? If yes, what is the crossover temp to the resistance heat coils?


Fujitsu - AOU24RLXFZH 
Advertised Compressor to work down to -15F  with ZH model.  

Not sure if it has a resistance coil.    You can google the model number if interested.


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## begreen (Feb 4, 2021)

Thanks. That's a new system for me. I will look into it. I like Fujitsu, they have been making good, super-efficient equipment for a long time. And I see they make a 3 ton unit too.


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## begreen (Feb 4, 2021)

UpStateNY said:


> Fujitsu - AOU24RLXFZH
> Advertised Compressor to work down to -15F with ZH model.


This appears to be for a non-ducted system. Their Fujitsu - FO3620RVJCAB is for ducted. It's not ultra low, but would have enough heat ouput at 20º to cover our house.


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## Woodspliter (Feb 6, 2021)

I ve been thinking about putting in a few singles in my 1100 Sq range one in the finished basement one in one living room kitchen area and a small 6k in the master bedroom.  I've looked into the top three in my opinion mitsubishi fujitsu and daikin. I'm leaning towards the mitsubishi for the sizing and btu output. People are pretty put off by the look of the indoor units but I don't mind them I'd rather look a one box on the wall than put a bunch on holes in my floor to install base board


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## begreen (Feb 6, 2021)

Woodspliter said:


> I ve been thinking about putting in a few singles in my 1100 Sq range one in the finished basement one in one living room kitchen area and a small 6k in the master bedroom.  I've looked into the top three in my opinion mitsubishi fujitsu and daikin. I'm leaning towards the mitsubishi for the sizing and btu output. People are pretty put off by the look of the indoor units but I don't mind them I'd rather look a one box on the wall than put a bunch on holes in my floor to install base board


So far it seems mainly Highbeam that strongly objects to the look of the wall units. They don't bother me. We have seen them so much in our travels around Asia that I take them for granted now. I have recommended and been in several houses with them, old and new. Quite frankly after a while you just ignore them.   However, these companies also make radiator style wall units and ceiling units as options.


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## Woodspliter (Feb 6, 2021)

Yeah I do like the floor unit, just a bit less efficient. The mitsubishi units are a nice bright white they will match the white trim work, may actually just complement the living room. Im just not sure about outdoor units I guess a little landscape can do the trick.  The single zones are the most efficient and have more output than the same size multi zone units


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## stoveliker (Feb 6, 2021)

Woodspliter said:


> I ve been thinking about putting in a few singles in my 1100 Sq range one in the finished basement one in one living room kitchen area and a small 6k in the master bedroom.  I've looked into the top three in my opinion mitsubishi fujitsu and daikin. I'm leaning towards the mitsubishi for the sizing and btu output. People are pretty put off by the look of the indoor units but I don't mind them I'd rather look a one box on the wall than put a bunch on holes in my floor to install base board



I have a mitsubishi system and I am very, very satisfied with it. I do not have the ultra low T system (being on Long Island where we get cold snaps but the sea moderates). Outdoor unit is MXZ-4C36NA2. Indoor units MSZ-GL18NA-U1 (and two 9 and one 6k units, instead of the 18k). 18k unit in the living/dining room with open kitchen. 6k unit in the basement mostly to dehumidify there (mitsubishi has a setting meant for that, where it keeps the temperature of the heat exchanger just below the room temp and keeps a constant low flow of air to maximize moisture condensation). I am not very enthusiastic about that; I still use the stand alone dehumidifier every now and then in summer to help the minisplit there.

I am quite surprised by how little energy they use, but that you can calculate for yourself using the COF.
What I'm even more happy about (having lived in the South with ducted central AC/heat) is the sound level. They are very quiet, both inside and outside. In fact when they installed the system, I opened a window when they started the outdoor unit, and I with my big mouth told them it was not working - being used to the big heat pumps from the South. It was working. You can't hear a thing. Only if you're within 3 ft can you hear a faint humming and the fan.

As I'm in moderate climate, with the stove, and an oil burning hydronic system, I'm only using the minisplit for heat when it's 35 or up outside. I may dial that down to lower temps when I get the hang of how many of my solar banked kWhs it uses. So far I use far less with it than I had expected.  I looked also at daikin, but for me mitsubishi just looked better.

I don't care about the looks - though my better half does. However, getting AC here (when we had none, not even window units "b/c they look trashy", according to the wife) beats all complaints here. 
Regardless, I don't think (apart from the very cold climate parts of the system of which I don't have knowledge) you can go wrong on any of these three brands.


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## Woodspliter (Feb 6, 2021)

Yeah I agree a either one of the three would be good. I am going to be getting the low ambient temperature units. We woukd Like to be able to step away from the stove as it is our main heat source. So I think this combo will be  great wood stove when it's super cold and heat pump the rest of the time. I love Bruning wood but I'd like to decrease our dependence on the wood stove


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## peakbagger (Feb 6, 2021)

Woodspliter said:


> I ve been thinking about putting in a few singles in my 1100 Sq range one in the finished basement one in one living room kitchen area and a small 6k in the master bedroom.  I've looked into the top three in my opinion mitsubishi fujitsu and daikin. I'm leaning towards the mitsubishi for the sizing and btu output. People are pretty put off by the look of the indoor units but I don't mind them I'd rather look a one box on the wall than put a bunch on holes in my floor to install base board



Its worth going to this site https://ashp.neep.org/#!/ and see what unit has the best cold weather performance.


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## Woodspliter (Feb 6, 2021)

Thanks peakbagger I have visited that site before kinds difficult to navigate. I looked on efficiency maine at the most popular rebates I know the mitsubishi probably don't have the best low temp heating temp and efficiency but seem to be a good overall unit. I'm just in the process of shopping a deal


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## peakbagger (Feb 6, 2021)

I think it comes down to if you are doing a self install or paying for a dealer to do it.


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## mcdougy (Feb 6, 2021)

peakbagger said:


> Its worth going to this site https://ashp.neep.org/#!/ and see what unit has the best cold weather performance.


Can you give an example of the fill in the blank numbers required for the product look up?


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## peakbagger (Feb 6, 2021)

Not that simple but pick a brand, Mitsubishi for example then a type, single zone, non ducted  wall placement, Now the tough part, for us folks in a cold zone you need to figure out your heat demand *you want at 5 degree F. and then enter that value.  You should now be able to sort and get bunch of models that meet the criteria. Now switch to List view and you will get spreadsheet that you can sort. My suggestion is sort descending for the zone IV HSPF.  That lists the most efficient heating units at top. If you are in heating dominant area HSPF is the heating efficiency, while SEER is the cooling capacity so you want the highest HSPF and may trade off a lower SEER. 

If you are trying to get a utility rebate, they usually have minimum requirements for SEER and HPSF. You may have to submit  a catalog cut in advance but it varies by utility. 

*how big of heating load is the $1000 question. A standard manual J heating calculation can be done for a range of outdoor temps. As the temps drop the heating demand goes up, while a heat pump puts out less heat the colder it gets outside.  Therefore if you have the potential for very cold outdoor temps like in Maine (minus 10 to 20) and you do not plan to have backup heat  then you need install a lot of heat pump capacity. You also need additonal capacity if you are bringing a place up from one temperature to a warmer temp like a seasonal cabin. Manufacturers rarely list the COP at below zero temps but as the temp drops, the COP may drop to 1 which is the equivalent of electric heat. If you have high power rates and lower cost backup source its up to you to do the math for what temp makes sense to heat exclusively with heat pumps.  The COP goes up as the outdoor temps increase.  If you pick a particular model you can get the COPs for higher temps.  

In my case and many others we have wood backup so we dont buy enough heat pumps to heat the house down to -20. We use the wood.I have a wood boiler so my threshold for my 12000 BTU Mitsubishi is around 20 degree overnight temps. As long as I set it and forget it,  it should keep my close to 1200 square foot well insulated main floor heated. I have a second floor office that adds another 500 square feet and if I leave my doors open I can carry both floors with my single unit with temps over 30 F. My minisplit is 10 years old and current models have a bit more efficiency and marginally better performance at very low temps. I have not heard from many folks happy with their heat pumps performance at less than 0 degrees. The heat mine puts out at sub zero temps is only somewhat warm and it defrosts often. I have run mine for the last couple of days so it nice break for few days from feeding the boiler.  Incidentally I can cool my main floor with this unit as long as I turn it on early on the hottest days.  I have an older 7500 BTU minisplit AC only unit in my office that cover my cooling in summer. When it dies I will probably replace with a cold climate unit and be able to heat it with the minisplt more efficiently than heating it from a lower floor.  BTW I have a solar system with net metering. I carry a surplus into the winter so its free heat and cooling in the summer.  

I am not the only one with very cold condition mini  split issues in Maine. I have mentioned in the past that I know someone who has sold Monitor vented kerosene heaters for decades (he was one of the first dealers in Maine), Monitor stopped production about 15 years ago so his business was ramping down keeping the ones out there still running. He and his daughter who runs the business are busier than ever as people are buying rebuilt units or Toyostove brand units to back up their minisplits during cold cold temps.


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## EbS-P (Feb 7, 2021)

I watched some of this video but not to the end and was surprised to see ceiling units for the zoned mini splits. The condensate plumbing was interesting to see.  Not cold weather but a good example of how versatile these units can be.  Evan


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## Brian26 (Feb 7, 2021)

Woodspliter said:


> Yeah I agree a either one of the three would be good. I am going to be getting the low ambient temperature units. We woukd Like to be able to step away from the stove as it is our main heat source. So I think this combo will be  great wood stove when it's super cold and heat pump the rest of the time. I love Bruning wood but I'd like to decrease our dependence on the wood stove



As much as I love burning wood  as well I am pretty much using them practically 24/7 here. I really only burn in severe cold outbreaks. Its just so easy to set the units to 70 with zero work required. Building small fires during shoulder season sucks. Way easier to run a split that costs pennies per hour to run.


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## Brian26 (Feb 7, 2021)

Woodspliter said:


> Yeah I do like the floor unit, just a bit less efficient. The mitsubishi units are a nice bright white they will match the white trim work, may actually just complement the living room. Im just not sure about outdoor units I guess a little landscape can do the trick.  The single zones are the most efficient and have more output than the same size multi zone units



I have a floor unit and a regular wall unit downstairs. The floor console in heating mode is vastly superior to the wall unit. It can direct air in 4 directions out both the top and bottom. In heating mode I usually have it go out the bottom on the floor. A huge advantage with the floor units is they are drawing in the cold air down low along the floor. Wall units are way up high drawing in the warmest air up by the ceiling. Ideal for cooling but not heating. 

I shot mine with my FLIR. You can see the nice heat it sends out along the floor.


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## stoveliker (Feb 7, 2021)

Brian26 said:


> I have a floor unit and a regular wall unit downstairs. The floor console in heating mode is vastly superior to the wall unit. It can direct air in 4 directions out both the top and bottom. In heating mode I usually have it go out the bottom on the floor. A huge advantage with the floor units is they are drawing in the cold air down low along the floor. Wall units are way up high drawing in the warmest air up by the ceiling. Ideal for cooling but not heating.
> 
> I shot mine with my FLIR. You can see the nice heat it sends out along the floor.
> View attachment 273937


Nice pic! My wall unit (high up) can also direct up (well, parallel to the ceiling), down, and left and right.
In my case they work very well, also for heating. Obviously I don't have a comparison as I don't have a floor unit (which would have interfered with the hydronic baseboard I also have).


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## Highbeam (Feb 8, 2021)

begreen said:


> So far it seems mainly Highbeam that strongly objects to the look of the wall units. They don't bother me.



I'm coming around to the look. At some point, as with the princess stove you strongly object to, the performance benefits exceed the aesthetic drawbacks. 

Myself, I've been looking at the MrCool DIY units again. The project is almost too easy with electrical being almost a bigger challenge than the actual heat pump.


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## semipro (Feb 9, 2021)

Highbeam said:


> Myself, I've been looking at the MrCool DIY units again. The project is almost too easy with electrical being almost a bigger challenge than the actual heat pump.


We installed a Mr. Cool Universal unit in July and I'm pretty impressed so far.   I need to post a review.  If anyone has any specific related questions I can probably provide some insight.  For instance, I discovered that while the compressor and exterior fan are variable speed the one in the air handler is not.  However, it does run at a different non-variable speed depending upon whether you're running in the 2 or 3 ton mode.  I was also initially unimpressed with the plastic exterior fan until I realized that the way it's shaped is one of the reasons the unit runs so quietly.  I'm assuming it would be tough to get the same complex shape from a metal fan.


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## Highbeam (Feb 9, 2021)

semipro said:


> We installed a Mr. Cool Universal unit in July and I'm pretty impressed so far.   I need to post a review.  If anyone has any specific related questions I can probably provide some insight.  For instance, I discovered that while the compressor and exterior fan are variable speed the one in the air handler is not.  However, it does run at a different non-variable speed depending upon whether you're running in the 2 or 3 ton mode.  I was also initially unimpressed with the plastic exterior fan until I realized that the way it's shaped is one of the reasons the unit runs so quietly.  I'm assuming it would be tough to get the same complex shape from a metal fan.



The standard wall units from mr.cool MUST have their refrigerant lines poke through the wall on the right side of the unit which is a problem for me. So I became discouraged and started reading about the universal central one again. 

I watched their video installing/retrofitting that unit in an old house in North Dakota and it sat there at -24 degrees making full output to keep the home above 70. Pretty impressive stuff. We barely ever get to single digits here. 

I think the blower speed on a ducted unit needs to be high enough to always keep flow to all of the vents on the duct. So if it were to roll really slowly like a wall unit there might be some rooms that get no heat.

I'm honestly afraid of ductwork. I have plenty of space in the attic to run the very simple ducts to just a few central rooms but I don't know how to fab up the return air filter, and the take off on top. It seems daunting.


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## sloeffle (Feb 9, 2021)

Brian26 said:


> As much as I love burning wood  as well I am pretty much using them practically 24/7 here. I really only burn in severe cold outbreaks. Its just so easy to set the units to 70 with zero work required. Building small fires during shoulder season sucks. Way easier to run a split that costs pennies per hour to run.


Can you expound on how many pennies per hour you are spending to run your mini-split ? And how many BTU's you are producing ?

For example - I have a Waterfurnace 5 series ( Envision when I bought it ) and it uses 2.2kW when running on the first stage. My installation method is via ground loop so my COP is around 4.4 according to the Waterfurnace manual. At my current electric rate it costs me 35 pennies per hour to run and it produces 31k BTU's.


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## Brian26 (Feb 9, 2021)

sloeffle said:


> Can you expound on how many pennies per hour you are spending to run your mini-split ? And how many BTU's you are producing ?
> 
> For example - I have a Waterfurnace 5 series ( Envision when I bought it ) and it uses 2.2kW when running on the first stage. My installation method is via ground loop so my COP is around 4.4 according to the Waterfurnace manual. At my current electric rate it costs me 35 pennies per hour to run and it produces 31k BTU's.



I have net metered solar so I don't actually buy the electricity.  Decent cold climate  mini splits though average around 1kw per ton of output with COP's around 3.5-4. I'm in CT where electricity is expensive around .24 kwh. If I did have to buy the electricity it would cost about .60 cents/hr to run both my 12 and 18k btu units at full output. They rarely ever run anywhere near full output though. I have electricity monitors on both mine and even on the coldest days I never use more than 15 kwh's day. That's for both units combined. In the 2 winters I have had them I have never used more than 500 kwhs a month. They provide probably 98% of my heating load.

I read that air source heat pumps are pretty much on par with geothermal now.  Minus the expensive ground loops. I self installed both my splits for less than $2500.


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## EbS-P (Feb 9, 2021)

My 3 ton heatpump is now 11 years old. Back then it was top of the line installed right before we bought the house.  I just looked at the data sheet. COP47 is 3.9 at 36k and COP17 is 2.7 at 21k.  All at about 2.3 kW. That’s not cold weather performance but it never gets and stays cold here.  My rough math I have been using and confirmed was about on average 12 12kw hrs a day at 0.12$ kw hr. Or about 50$ a month. 
This is a package unit and even today you can’t get a package unit that is more efficient.  Hence why you are seeing more mini splits even here in the southern part of the US.


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## sloeffle (Feb 10, 2021)

Brian26 said:


> I read that air source heat pumps are pretty much on par with geothermal now.  Minus the expensive ground loops. I self installed both my splits for less than $2500.


If I was doing the same installation today I would probably choose a ASHP over geothermal due to the COP's being about the same for heating. If I was in a cooling dominated climate I think geo is still the way to go. Not unless you are heating / cooling a big house I don't think the ROI is there anymore for geo over ASHP. The two nice things about geo are, you don't have to listen to the compressor outside of the house run, and at least in my situation the cooling is dirt cheap. I spend about $5 - $10 a month (  .16kWh ) to cool my house and make hot water during the summer.  I don't think you can do that with a conventional unit.

To give you some perspective on price, I paid 17k 10 years ago for my system. I however got a 1k back from the electric company and the government at that time had a 30% or 33% tax credit. After those two "rebates" it actually brought the prince inline with a bid I got for  Trane ASHP / propane furnace. That's why I went the geo route. I got one geo quote that was as high as 26k. I would love to know the markup on a quote like that.


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## Brian26 (May 28, 2021)

These cold climate splits also have some incredible cooling performance. I have electricity monitors and I pretty much left both my splits set to 72 for the month of May. It was warm here with many days in the 80s and some 90s. Total electricity consumption was only 100 kwh! Its incredible watching the electricity monitor of the unit drawing less than 100 watts and blasting out cold air. 

I have a 30.5 Seer 12k gree Sapphire and 24 Seer 12k Midea Premier. The Gree carries most of my cooling load. This thing has some insane cooling efficiency. At its minimum capacity at 95 degrees it has a COP of 10.62 and is only drawing 80 watts.






						ASHP
					






					ashp.neep.org


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## ABMax24 (May 30, 2021)

Brian26 said:


> These cold climate splits also have some incredible cooling performance. I have electricity monitors and I pretty much left both my splits set to 72 for the month of May. It was warm here with many days in the 80s and some 90s. Total electricity consumption was only 100 kwh! Its incredible watching the electricity monitor of the unit drawing less than 100 watts and blasting out cold air.
> 
> I have a 30.5 Seer 12k gree Sapphire and 24 Seer 12k Midea Premier. The Gree carries most of my cooling load. This thing has some insane cooling efficiency. At its minimum capacity at 95 degrees it has a COP of 10.62 and is only drawing 80 watts.
> 
> ...



That's really cool (pun intended), and impressive performance curves. I really do have to question that COP of 10.62 however, I'm thinking there is some error in that number, I thought theoretical maximum COP was somewhere around 8. In fact I have to question all those min values, they all seem overly optimistic to me.


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## CaptSpiff (May 30, 2021)

Brian26 said:


> I have a 30.5 Seer 12k gree Sapphire and 24 Seer 12k Midea Premier. The Gree carries most of my cooling load. This thing has some insane cooling efficiency. At its minimum capacity at 95 degrees it has a COP of 10.62 and is only drawing 80 watts.
> 
> 
> View attachment 279119



I'm wondering if that 80 watts isn't just your inside unit fan ?!?


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## EbS-P (May 30, 2021)

ABMax24 said:


> That's really cool (pun intended), and impressive performance curves. I really do have to question that COP of 10.62 however, I'm thinking there is some error in that number, I thought theoretical maximum COP was somewhere around 8. In fact I have to question all those min values, they all seem overly optimistic to me.


I have seen these number on this unit. I just can’t imagine the case where they are real world repeatable numbers.  For the sole fact that if the tech was out there why is Mitsubishi not offering anything similar?  I think there is evidence that they are very efficient  but a COP>10..... if it was true that’s a gold mine, or a loophole, rounding error in their favor on the standard test like the flow meter only measures in units of 50 cfm and whole degrees Celsius.  When turned way down those rounding errors could be used in your favor.  That said if I could be assured that the warranty would be honored I would be very tempted to install one. 

Evan


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## maple1 (Jun 4, 2021)

stoveliker said:


> Nice pic! My wall unit (high up) can also direct up (well, parallel to the ceiling), down, and left and right.
> In my case they work very well, also for heating. Obviously I don't have a comparison as I don't have a floor unit (which would have interfered with the hydronic baseboard I also have).



Just as a general FYI to anybody reading, a floor unit can be installed above baseboard. Ours is. They are called floor units but are still fastened to the wall. A bit of a misnomer. You could put one anywhere on a wall you wanted, but they are at their best when heating when mounted way down low. As Brian's IR pic shows. A very big and very noticeable advantage over wall mounts up at the ceiling.


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## Woodspliter (Jun 4, 2021)

maple1 said:


> Just as a general FYI to anybody reading, a floor unit can be installed above baseboard. Ours is. They are called floor units but are still fastened to the wall. A bit of a misnomer. You could put one anywhere on a wall you wanted, but they are at their best when heating when mounted way down low. As Brian's IR pic shows. A very big and very noticeable advantage over wall mounts up at the ceiling.



Id like to know where maple is getting his information from, all the research ive done on heat pumps the wall mounted uints have better Seer and Hspf ratings than the floor uints. Is there something im missing?


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## stoveliker (Jun 4, 2021)

I think that  injecting heat at floor level is more efficient in heating (or experiencing a good climate inside) as compared to injecting heat up high.

Of course the trade off is that cooling in summer works less well. So it's important to assess what is more important for your situation.


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## maple1 (Jun 4, 2021)

Woodspliter said:


> Id like to know where maple is getting his information from, all the research ive done on heat pumps the wall mounted uints have better Seer and Hspf ratings than the floor uints. Is there something im missing?



Living with one unit of each type of the same btu ratings. The floor mount feels warmer. The air currents from a high up wall mount can lead to less comfort. Especially when they're defrosting.  And I think they sometimes can create a small gradient so it is cooler in the room down low where you're sitting maybe depending where you're sitting. I dont think I compared their spec sheets but now you've got me curious.


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## peakbagger (Jun 5, 2021)

I heat both a main floor and part of a second floor with single minisplit. I think the standard high mount gets the heat to the second floor quicker.


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## maple1 (Jun 5, 2021)

peakbagger said:


> I heat both a main floor and part of a second floor with single minisplit. I think the standard high mount gets the heat to the second floor quicker.



Yes, I agree. Our living room high mount points toward a doorway, outside of which is a landing at the bottom of our stairway to the second floor. It is noticeably warmer at the top of those steps than it is in the room the unit is in, down low and off to the side of it. Which is where our love seat facing the TV is . Heat rises, which is the simple reason for the differences in high mount vs. low mount overall feelings of comfort when heating .


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## Brian26 (Jun 5, 2021)

Woodspliter said:


> Id like to know where maple is getting his information from, all the research ive done on heat pumps the wall mounted uints have better Seer and Hspf ratings than the floor uints. Is there something im missing?



Not the case with my Midea floor console. My floor console has better efficiency numbers and a lower min capacity than the high wall unit on the same  outdoor condenser. I think the coil surface area is larger and more efficient on the floor console as its square.


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## MikeT2 (Jun 5, 2021)

Question for the group-
I currently have a propane boiler and a gasifier wood boiler on the same system in Vermont. Wood boiler runs in the winter and propane heats the DHW in summer.  I have two wood stoves for shoulder season usage and supplemental.  I have radiant floors except for the second floor which has two smith power radiators.
The wood boiler is rated at 140,000 BTU and handles winter except for really bitter cold stretches (below zero times) and then a wood stove is lit off to help.
 I believe the 140 degree ASHP would work quite well for the shoulder seasons and DHW for summer.  I can get a grant of $6500 towards a single ASHP.
My thinking is to replace the times the wood boiler is in use, I would need two ASHP units. Not going to do that. If I got just one, would it be too undersized to work in the shoulder seasons? 
I would consider getting a ASHP water heater, but they do appear to be quite expensive for what you get unless I am wrong there.
I thought about a few mini-splits and I can get  a $650 rebate but this appears to be a very large expense
Thanks!


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## maple1 (Jun 5, 2021)

MikeT2 said:


> Question for the group-
> I currently have a propane boiler and a gasifier wood boiler on the same system in Vermont. Wood boiler runs in the winter and propane heats the DHW in summer.  I have two wood stoves for shoulder season usage and supplemental.  I have radiant floors except for the second floor which has two smith power radiators.
> The wood boiler is rated at 140,000 BTU and handles winter except for really bitter cold stretches (below zero times) and then a wood stove is lit off to help.
> I believe the 140 degree ASHP would work quite well for the shoulder seasons and DHW for summer.  I can get a grant of $6500 towards a single ASHP.
> ...



What exactly are you referring to by '140 degree ASHP'?


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## MikeT2 (Jun 5, 2021)

The newer Air source heat pumps can produce 140 degree water


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## maple1 (Jun 6, 2021)

MikeT2 said:


> The newer Air source heat pumps can produce 140 degree water



Ok. Lots of variables to the questions in your first post that go way beyond the output temp of the ASHP alone. You'd need to know its overall btu output and at what inlet temp or dt. E.g., how many gpms would it flow at what dt with inlet temp of say 100 or 120? A cold inlet temp say from heating dhw, of say the 60-70 area, would be capable of pulling more BTUs out of the heat pump. Then there's your distribution system. Radiant floors dont need as high input temps as say baseboard but there is still an overall btu requirement for a given outside temp or overall heat loss.  (Plus DHW demand). If things match up on each side, then maybe? But there's also equipment costs to factor in and paybacks. No idea how much the heat pumps cost that you're speaking of. They haven't really hit where I'm at yet. That sounds like a real fat grant figure, are you sure that's not for geothermal?


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## peakbagger (Jun 6, 2021)

Yes they can put out 140 degree F but far less of it at lower a COP.


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## Highbeam (Jun 12, 2021)

Not yet, but the ashp tech is coming. Currently just marketing.


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## Komrade (Sep 9, 2021)

Does anybody know if there is a list of high efficiency water heating appliances that are sold in US?

I've looked at Sanden, but it's low BTU (15k) is insufficient for heating. 
I've briefly looked at Chiltrix, does not seem to have very good reputation.

Looks like there is LG Monobloc, but it don't appear to be avail in US based on what I can find. I am sure there are others from big name manufacturers.


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## sloeffle (Sep 9, 2021)

Komrade said:


> Does anybody know if there is a list of high efficiency water heating appliances that are sold in US?











						Product Finder — ENERGY STAR Certified Water Heaters
					

Compare ENERGY STAR Certified Water Heaters, find rebates, and learn more.




					www.energystar.gov


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## Highbeam (Sep 11, 2021)

sloeffle said:


> Product Finder — ENERGY STAR Certified Water Heaters
> 
> 
> Compare ENERGY STAR Certified Water Heaters, find rebates, and learn more.
> ...



I think he means space heating, not domestic water heaters.

I wish the market would catch up on space heating heat pump water heaters. We know the tech is there but just not readily available in North America.


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## Brian26 (Sep 12, 2021)

Highbeam said:


> I think he means space heating, not domestic water heaters.
> 
> I wish the market would catch up on space heating heat pump water heaters. We know the tech is there but just not readily available in North America.


I agree.  Almost all the air to water heat pumps are  self contained outdoor units that require just running the water lines to the outdoor units. No refrigerant lines, vacuum or pressure testing is required. It seems like they would be easy to install  since the refrigerant system is factory sealed. 

 Efficiency Vermont is giving out a $1k per ton rebate for these units now. The issue appears most units can only produce 110 degree water at 5 degrees according to the VT list. The COP's seem to be around 2 at 5 degrees.  

I think once they can get units to put out close to the 180 degree water temps that most fossil fuels hydronic units can easily obtain these will become more popular. 







						Air-to-Water Heat Pumps | Efficiency Vermont
					






					www.efficiencyvermont.com


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## sloeffle (Sep 13, 2021)

Highbeam said:


> I think he means space heating, not domestic water heaters.
> 
> I wish the market would catch up on space heating heat pump water heaters. We know the tech is there but just not readily available in North America.


Ahhhhh yeah, you are right based off of the list he had.


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## Brian26 (Oct 8, 2021)

Looks like Mitsubishi upgraded their hyper heat models with a new deluxe model called H2i Plus. It has a significant jump in cold weather cop's and capacity. They are now rated to 100% heating capacity at -5.

I believe the prior version had 100 capacity to 5 degrees  with a cop of less than 2 so quite an improvement.


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## EbS-P (Oct 8, 2021)

Brian26 said:


> Looks like Mitsubishi upgraded their hyper heat models with a new deluxe model called H2i Plus. It has a significant jump in cold weather cop's and capacity. They are now rated to 100% heating capacity at -5.
> 
> I believe the prior version had 100 capacity to 5 degrees  with a cop of less than 2 so quite an improvement.
> View attachment 283005
> View attachment 283006


COP of 2 at -5F….   Impressive but not a large increase.    So you figure your ideal load and order a 1/2 ton larger and I thing these would work many many people.  I want to see output at -30 if I lived where it got really cold.  I don’t care about the COP at that temp. 
Evan
Hvac design temps below 



			https://www.captiveaire.com/catalogcontent/fans/sup_mpu/doc/winter_summer_design_temps_us.pdf


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## stoveliker (Oct 8, 2021)

Though, 10-20000 BTU per HR may not cut it at -5  F...


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## EbS-P (Oct 8, 2021)

stoveliker said:


> Though, 10-20000 BTU per HR may not cut it at -5  F...


500-1000 sq ft per ton…..  no they are not for big spaces.  But a single mini splits is not really not  for whole house heat.   And I don’t like the idea of heat pump as the only heat source.  If a mini split could handle even 50-75% of the heating load that a great reduction in fossil fuel consumption.


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## maple1 (Oct 8, 2021)

EbS-P said:


> 500-1000 sq ft per ton…..  no they are not for big spaces.  But a single mini splits is not really not  for whole house heat.   And I don’t like the idea of heat pump as the only heat source.  If a mini split could handle even 50-75% of the heating load that a great reduction in fossil fuel consumption.


Yessir. It is rather amazing how much of whatever other fuel you use, that a heat pump will reduce by using it just in shoulder seasons. My old wood oil boiler used a tank of oil and maybe 8 cords of wood a year. Switching to the gasifying boiler and storage got that down to maybe just 5 cords of wood with no oil. Added 2 heat pumps and I think I am down to 3 cords of wood. Plus now have really cheap a/c and dehumidifying.


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## begreen (Oct 8, 2021)

Their product line is a bit confusing for ducted systems pairing. It doesn't look like the H2i version is available in a 4 ton ducted version.


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## peakbagger (Oct 8, 2021)

Hard to beat shoulder season use. On a clear night it will cool down quite a bit and stay cool until the sun is up for an hour or two. I run mine when I get up and once the sun starts coming in I turn it off.  Once I have 24/7 heating demand I will start running the wood boiler but still will use the mini split on sunny days.


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## maple1 (Oct 8, 2021)

We liked ours so much we got another one put in last weekend,  at our cottage. Another Daikin. We're there right now for our first Thanksgiving weekend away from home. Rest of the family coming tomorrow. Still made a fire on in the stove when we got here, as much for ambiance as anything else  but nice to have the cheap easy heat source. Especially getting up in the morning.


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## EbS-P (Oct 8, 2021)

begreen said:


> Their product line is a bit confusing for ducted systems pairing. It doesn't look like the H2i version is available in a 4 ton ducted version.


Try to get a southern HVAC tech to look into that when you argue that you want the system size for heating not cooling.  I just told them the model numbers to quote.


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## Brian26 (Oct 9, 2021)

It also looks like they really improved the capacity range on the new Mitsubishi as well. The 6 and 9k units can turn down to some really low numbers and just sip electricity. At 47 degrees at minimum speed the inverter is only using 110 watts to deliver 1600 btu/h.  With such a low output it would be really hard to oversize one of these. Its also interesting that it can deliver twice its rated capacity at 47 degrees. It's low speed cooling is pretty impressive as well using only 90 watts for a cop of 6.13.

It seems Mitsubishi is using the full heat output at -5 to rate the capacity on these.

The chart is for the 9k.






						ASHP
					






					ashp.neep.org


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## EbS-P (Oct 9, 2021)

So here is the data for my trane 16xl 3 ton package unit manufactured in 2009. 
COP17 is 2.55.  
Yes it’s lost 33% capacity. 

it seems all the efficiency gains are being spent on increasing capacity at low temps with these new units. Which is a good thing.   I’d like to have that extra ton I’ve lost when it gets cold.


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## Wiess (Oct 23, 2021)

maple1 said:


> We liked ours so much we got another one put in last weekend,  at our cottage. Another Daikin. We're there right now for our first Thanksgiving weekend away from home. Rest of the family coming tomorrow. Still made a fire on in the stove when we got here, as much for ambiance as anything else  but nice to have the cheap easy heat source. Especially getting up in the morning.


Did you add a second head to an existing outside unit or additional outside unit too?  The local Daikin dealers are suggesting the multi-head units and the Fujitsu dealer is suggesting two separate units, one per floor, and are a higher price.  The federal grant is nice too!


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## maple1 (Oct 23, 2021)

Wiess said:


> Did you add a second head to an existing outside unit or additional outside unit too?  The local Daikin dealers are suggesting the multi-head units and the Fujitsu dealer is suggesting two separate units, one per floor, and are a higher price.  The federal grant is nice too!


All individual separate units. Our Daikin guy highly recommended doing it that way. I couldn't understand exactly why at the time, but I think he was right.


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## Brian26 (Oct 24, 2021)

maple1 said:


> All individual separate units. Our Daikin guy highly recommended doing it that way. I couldn't understand exactly why at the time, but I think he was right.


Sounds like your installer knew what he was doing. Single 1 to 1 splits have superior efficiencies and turn down ratios to multi splits with more than one head on the same condensers.  The outdoor units on multi splits have really high minimum capacities and they are still pumping refrigerant through heads even if they aren't on.  A single 1 to 1 12k unit can turn down to a few hundred btu/h while a large 24k btu multisplit can only turn down to often 6k or more btu/h. I read that Maine did a study and found most of them were installed incorrectly and way oversized and their efficiencies Their were terrible. The state heat pump incentive is now longer offering a good incentive for them and it only applies to single 1 to 1 splits.


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## Wiess (Oct 24, 2021)

It sounds like I need revised quotes from the Daikin folks for separate units.  They initially quoted the MXL Aurora Series with two indoor heads with one outdoor unit, plus an optional third head for the master bedroom.   One indoor unit per floor, located at opposite ends of the house due to the layout.  The individual components are listed on the NEEP site but not the complete system.   They also proposed to run lines in my attic which is not my preference since we recently topped up the insulation to R50.

The Fujitsu proposal includes two separate units, a single indoor head connected to one outdoor unit.  The outdoor units also installed at opposite ends of the house.  Data from the NEEP site is included below.

In terms of quality - how do you rate Daikin and Fujitsu?  Mitsubishi?


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## maple1 (Oct 24, 2021)

Sounds like using only 1 outside unit is leading to running more line sets where you might not want them to go. Another reason to go individual pairs. A lot easier to run a 240v wire source, than a line set. I dont think I would want any part of any heating system going through my attic.

IMO Daikin,  Mitsu & Fujitsu are the big 3. Have not kept up lately but Mitsu might have recently pulled ahead a little bit, efficiency wise? Also, scrutinize warranty details. And what they cover and for how long. Notably, labour.


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## EbS-P (Oct 24, 2021)

maple1 said:


> I dont think I would want any part of any heating system going through my attic.


It’s pretty standard practice for slab on grade construction.  I agree if I I had a choice I would avoid it. And I would want to avoid condensation pumps. But sometimes it’s not possible


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## maple1 (Oct 24, 2021)

Brian26 said:


> Sounds like your installer knew what he was doing. Single 1 to 1 splits have superior efficiencies and turn down ratios to multi splits with more than one head on the same condensers.  The outdoor units on multi splits have really high minimum capacities and they are still pumping refrigerant through heads even if they aren't on.  A single 1 to 1 12k unit can turn down to a few hundred btu/h while a large 24k btu multisplit can only turn down to often 6k or more btu/h. I read that Maine did a study and found most of them were installed incorrectly and way oversized and their efficiencies Their were terrible. The state heat pump incentive is now longer offering a good incentive for them and it only applies to single 1 to 1 splits.



Yes, he is pretty good. He has been putting Daikins in for quite a while now, and told me they have been working out really well since day 1 with far far fewer call backs than he was anticipating there might be.


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## begreen (Oct 25, 2021)

Wiess said:


> In terms of quality - how do you rate Daikin and Fujitsu? Mitsubishi?


All good. I rarely hear bad words about them. The Fujitsu 1 ton units went in early locally and folks love them. The only problem I have heard about is that they are power outage/voltage surge sensitive.  Surge protection is a worthy investment.


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## Brian26 (Nov 3, 2021)

With record high oil and gas prices heat pumps will bring some huge savings to some this winter.  Here is a look at Maine. I go the fuel prices from the states heating fuel tracker and used the EIA average electricity price(.17) in the state. 

Per million BTU.

Propane at $3.21.                 $45.76
Heating oil at $3.5.               $29.12
Heat pump at COP of 4.     $12.46






						Heating Fuel Prices | Governor's Energy Office
					

The Governor’s Energy Office (GEO) conducts a weekly survey of heating fuel prices, obtained from fuel retailers statewide. This survey provides the current Maine cash prices, in dollars, rounded to the nearest penny. Prices are typically updated on Thursdays.  Maine Retail Heating Fuel Prices...




					www.maine.gov


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## peakbagger (Nov 3, 2021)

Kind of an overly simplistic comparison especially for Maine. The COP for heat pumps you use is overly optimistic, even with the latest and greatest tech the COP plummets as temps go down as the heating load goes up.  I agree there are savings but in order to come up with an estimate there is going to have be a comparison of design temps and heating load versus actual COP at design temps. A COP of 2 is better than resistance heat but probably a better average for winter heating. Realistically even the state admits that heat pumps are not primary heating sources unless equipped with a supplemental heating source.  So any estimate would need to blend in electric resistance heat, Kerosene, natural gas, propane or heating oil for periods below zero when heat pumps really start to have tough time putting out reasonable temperature heat at a low COP. 

I am involved to some extent with large commercial and institutional projects in Mass that sell thermal recs from heat pumps (air and geothermal) savings and we consistently are seeing that real world heating efficiency is less than predicted on these buildings and backup heat is needed more often in cold weather. The owners are not happy but they just pass the costs onto tenants.


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## Brian26 (Nov 3, 2021)

peakbagger said:


> Kind of an overly simplistic comparison especially for Maine. The COP for heat pumps you use is overly optimistic, even with the latest and greatest tech the COP plummets as temps go down as the heating load goes up.  I agree there are savings but in order to come up with an estimate there is going to have be a comparison of design temps and heating load versus actual COP at design temps. A COP of 2 is better than resistance heat but probably a better average for winter heating. Realistically even the state admits that heat pumps are not primary heating sources unless equipped with a supplemental heating source.  So any estimate would need to blend in electric resistance heat, Kerosene, natural gas, propane or heating oil for periods below zero when heat pumps really start to have tough time putting out reasonable temperature heat at a low COP.
> 
> I am involved to some extent with large commercial and institutional projects in Mass that sell thermal recs from heat pumps (air and geothermal) savings and we consistently are seeing that real world heating efficiency is less than predicted on these buildings and backup heat is needed more often in cold weather. The owners are not happy but they just pass the costs onto tenants.


I was going off a HSPF of 12-15 which equals out to a COP of around 4  for the course of a heating season.  Those HSPF's numbers  are common on heat pumps purchased the last few years. Maines heat pump rebate even requires a 12 or higher hspf to qualify for the  bigger rebate.


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## peakbagger (Nov 3, 2021)

The problem with HSPF is published figures are for zone 4 heating which is fine for CT but Maine NH Vt and NY is zone 5 and arguably Northern Maine, NH and VT should be a zone 6 (if one existed). It great for comparing units just like EPA mileage figures but there are too many assumptions  baked into it to calculate actual energy use.

 I get it that you live in CT and you are in great location for minisplits but you need to be really careful to misrepresent a minisplits capabilities in a colder climate than you experience.  There is big institutional and political bandwagon to get these installed for legit reasons everywhere including Maine NH and VT and in general they tend to over sell minisplits in very cold climates. The realists are not getting paid the big bucks to point out the potential issues and a result the media ignores them since they dont buy big media buys . As supplemental heating in cold climates during shoulder seasons and warm days I am right with you (mine is running today at 30 F) but there is big pool of practical experience out there that they just do not make it as primary heating source during temps much below 20F in typical older housing stock. Yes they will run down lower but then you start running into the Quality of Heat issue which  is far more subjective. Homes are drafty and a typical minisplit high wall installation leads to temperature stratification in room. That means a higher set point temp compared to radiant or baseboards (pretty common in colder climes) Sedentary folks sit lower in a room and frequently near windows that are sources of drafts. Baseboards tend to be located under drafty windows so the effect of the windows is lessened to some extent. That problem is opposite with minisplit, the heat from the minisplit tends to be sent to the center of the room with quite a hihg volume.  The high fan speeds recomended to get the maximum efficiency out of the heat pump are loud enough to be annoying to many folks and the high fan speeds tend to drop the exit air temp. Unless we want to bring up entropy a BTU is BTU but to homeowner 10,000 cfm of tepid air a couple of degrees above room temp is worth a lot less than a lesser amount of 100F air coming out of hot air system.  So the typical homeowner approach is to crank up the setpoint.


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## EbS-P (Nov 3, 2021)

COP17 is a good number that I think is meaningful for Mainers.  Again I don’t see heatpumps as a stand-alone heating system for cold climates yet. bJanuary average temps for Bangor are 26 high and 9 low.  Coldest morning I woke up it was -30F.  How much heat can you pump out of -20 to -30 air? 

But with a heatpump thoughtfully run, I imagine it could cover 1/2 -3/4 of your heating needs.  Which is meaningful. I imagine oil prices will see a steady increase over the next decade. (I think electricity prices will also increase to cover infrastructure expansion/upgrades but not by as much as oil).


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## peakbagger (Nov 3, 2021)

I agree that it will easily cover 1/2 to 3/4  of the heating load but that means the homeowner has to keep their backup heating system operational.  As I have mentioned in the past, I know of a supplier of vented#1 heating oil  heaters that is selling a lot of them for that purpose. They are strictly space heaters but they do not take much power to run on generator if the power goes out and they throw out a lot of heat for their size.


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## Brian26 (Nov 3, 2021)

I think I read that like over 60% of Maines population  lives either along the coast or in the Portland area. I choose Maine as the state publishes weekly data comparing fuel costs. It looks like the state uses a cop of around 3.5 for heat pumps. 






						Residential Heating System Cost Calculator | Efficiency Maine
					

Our heating cost comparison calculator can help you estimate your annual home heating costs for different heating systems.




					www.efficiencymaine.com


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