Is a heat pump the right choice for us?

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Fire2020
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Is a heat pump the right choice for us?

Post by Fire2020 »

We are the new owners of a large (7,200 sqft) one of a kind house that is in need of new heating systems.

Currently we have two boilers that are about 20 years old (198,000 btu's each). They have probably never been serviced, seem to use ridiculous amounts of gas, and do a pathetic job heating certain parts of the house. Last winter we heated some rooms via the boilers, closed down some rooms and heated other areas with a wood burning stove. We went through about 2,500 gallons of propane, ten cords of hardwood and still had a cold house. Local temps in January vary from a high of 34 to a low of 15 degrees. February is 40 to 20, March is 50 to 30 etc. We have nest thermostats with 13 zones, so we know when the heat is cycling on and off.

We are potentially looking to replace at least one of the gas furnaces with a heat pump but would like to know what to expect as far as electricity usage.

Most of the house has decorative concrete floors with radiant in-floor heating. Other rooms have cast iron radiators. Not much passive solar to speak of in most of the house.

In general, the house is made of lots of real stone along with brick and wood on both the interior and exterior walls. We often have to open the windows to let in some heat this time of year when it's 64 inside and 70 outside.

That's a lot of information I know. I think we have a few problems contributing to our massive heating bill (old boilers, big house, thermal mass etc). We're hoping a heat pump will help a lot, but it's not cheap. The other option is just replace the boilers with new high efficiency boilers.
Big price difference $30K vs $18K per boiler, and we have two. We pay 10 cents a KWh off peak, 20 during peak. Propane is now $2.60 a gallon if you pre-buy.
cmr79
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Re: Is a heat pump the right choice for us?

Post by cmr79 »

I am a big fan of heat pumps and have an air-source heat pump to supplement my propane furnace which dramatically reduces our annual propane usage. That being said, you have a unique and very large home with radiator heating in at least some parts, with currently inadequate heating from your boilers. Appropriately choosing and sizing a heat pump will require a lot more information and expertise than you are likely to find here. I recommend getting a professional HVAC opinion, as most of the prior discussions here about ducted vs mini split systems may not apply to your intended use, and also considering a home energy audit to see whether there are more easily remedied (insulation, door or window issues) problems to deal with your inadequate heating problem.
twh
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Re: Is a heat pump the right choice for us?

Post by twh »

Few things...

I do not like Nest thermostats. Too much guessing going on. I know the schedule and I just want the schedule. I cannot imagine 13 zones on Nest -- that sounds like a nightmare all by itself and that is likely part of your problem.

If you do replace, you might want to consider dual-fuel systems. That way you can leverage the best price and if you need that extra jolt that hydrocarbon heating provides, you can leverage that as well.
adamthesmythe
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Re: Is a heat pump the right choice for us?

Post by adamthesmythe »

If you own an immense house as described you must not be very price-sensitive. Just hire an HVAC company and tell them to do what it takes.

A couple thoughts though. While HVAC tuneups are probably not very useful if the furnaces haven't been cleaned in many years there may be some efficiency to be gained by having them cleaned and checked. If you replace there is usually a range of furnace efficiencies. The gains between the very highest efficiency and just pretty good efficiency are probably not worth the extra cost.

I am amazed by 13 heating zones.
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TomatoTomahto
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Re: Is a heat pump the right choice for us?

Post by TomatoTomahto »

Our main house is a bit smaller (6,000 SF) and we replaced oil with geothermal (4 main zones). It had more zones previously, but we have been fine with just 4 zones. Initial costs are high, but our operating expenses are minimal.

Boston weather is not a problem.
I get the FI part but not the RE part of FIRE.
Designairohio
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Re: Is a heat pump the right choice for us?

Post by Designairohio »

Is it even possible to add the ductwork you would need for the heat pump?
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kevinf
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Re: Is a heat pump the right choice for us?

Post by kevinf »

Fire2020 wrote: Sun May 28, 2023 1:18 pm We are the new owners of a large (7,200 sqft) one of a kind house that is in need of new heating systems.
You'll get much better advice at https://forum.heatinghelp.com
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leeks
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Re: Is a heat pump the right choice for us?

Post by leeks »

My guess is that you need the radiators if you live somewhere with cold winters and maybe some repairs to that system can improve it. Can you get natural gas instead of heating oil? Perhaps combined with a heat pump that runs during milder days but switches over to the boilers during colder times?

Or if you have enough land, can you dig wells for a geothermal heat pump?

Get quotes/advice from at least two high quality HVAC companies in your area. If the two propose very different solutions, get a third opinion. And once you get new systems, have them properly serviced every year.

And get a home energy audit, the kind where they do blower door tests and inspect with an infrared camera, to inform about options to improve the home's efficiency. There is likely low hanging fruit in terms of air sealing and insulation to improve heat retention.

But seriously this is not a DIY project. You need expert help for that mansion/inn!
sailaway
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Re: Is a heat pump the right choice for us?

Post by sailaway »

adamthesmythe wrote: Sun May 28, 2023 2:52 pm If you own an immense house as described you must not be very price-sensitive. Just hire an HVAC company and tell them to do what it takes.
That does not follow. A lot of people splurge on one thing or another and are frugal in most other ways.
blueberrypi
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Re: Is a heat pump the right choice for us?

Post by blueberrypi »

How much of that space do you routinely use? Installing a few high efficiency heat pumps in the commonly used areas could help. I just had a mini split installed on my lower level and think it will make a huge difference next winter. My house probably fits in your master bedroom however :beer
BerkeleyChris
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Re: Is a heat pump the right choice for us?

Post by BerkeleyChris »

+1 to look into a ground source heat pump system to replace both furnaces. My parents have had such a system for about 15 years that works very well. It does both heating and cooling, radiant heat in concrete floors and forced air, each room with its own thermostat. It can also provide potable hot water as the main or backup system.
beardsicles
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Re: Is a heat pump the right choice for us?

Post by beardsicles »

Designairohio wrote: Sun May 28, 2023 3:01 pm Is it even possible to add the ductwork you would need for the heat pump?
You can, within reason. We did partially ducted heat pump in a floor of our house. But nothing on the scale of OP’s house. Given the scale, the solution is almost certainly geothermal heat pumps. Especially given the substantial tax credit.
bendix
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Re: Is a heat pump the right choice for us?

Post by bendix »

Radiant heating systems tend to get dysfunctional bit by bit if air accumulates in the tubes, which it usually does earlier or later. My first approach here would be to have air removed from the hot water tubes and when I had radiant heating this would always do the trick. I´d exhaust this before even thinking about expensive replacements.
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Bengineer
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Re: Is a heat pump the right choice for us?

Post by Bengineer »

OP, I think I would want to first understand what I have.

First:
  • How good is the air sealing in the house / Where are the big air leaks?
  • What is the current R-value of the insulation in the floors/walls/ceiling?
  • Single or double pane windows? Area? R-value? U-value?
  • What is the calculated heating load at the design temperature for the location?
  • Are the radiant floor heating system controls set up for best practices? Constant temperature seems right. Thermostats? Pumps?
  • Are the boilers performing to design efficiency? 396kbtu seems very large.
  • Do the zones hold set point? If all the zones are set to a constant temperature, does each maintain the temp?
Then what I can improve my comfort, possibly cost-effectively:
  • Can I / will it improve my comfort / be cost effective to improve the air sealing?
  • Can I / will it improve my comfort / be cost effective to improve the insulation?
  • Can I / will it improve my comfort / be cost effective to improve the heating system or change the technology?
It might seem like a lot of details and there are for a house and systems as you describe. The payoff is being comfortable and knowing your systems are as they should be.
adamthesmythe
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Re: Is a heat pump the right choice for us?

Post by adamthesmythe »

sailaway wrote: Sun May 28, 2023 3:29 pm
adamthesmythe wrote: Sun May 28, 2023 2:52 pm If you own an immense house as described you must not be very price-sensitive. Just hire an HVAC company and tell them to do what it takes.
That does not follow. A lot of people splurge on one thing or another and are frugal in most other ways.
True. The English aristocracy deals with a similar problem by closing off all but a few rooms.

Given the scale of OP's problem, any complete solution is going to involve lots of money.
Carl53
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Re: Is a heat pump the right choice for us?

Post by Carl53 »

Prior home had an ground source heat pump that heated/cooled (water to air) as well as heated the hot water (water to water) and pool (water to water) but ultimately became a problem when the foreign manufacturer went out of business and I needed a replacement heat exchanger. That said here is a Bosch installation description that might be similar to your needs. https://www.bosch-homecomfort.com/us/me ... s_1_us.pdf
They have several other case studies presented. https://www.bosch-homecomfort.com/us/en ... e-comfort/

In any case, I think you need a top notch professional that will provide a manual J calculation of what your requirements truly are.
hvaclorax
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Re: Is a heat pump the right choice for us?

Post by hvaclorax »

Compare your BTU consumption per square foot to similar home in your climate zone. You won’t find an exact fit but by comparison and then using efficiency numbers for each source you might find your home isn’t that far from average for your situation.
Propane is expensive and Heat pump might be cheaper. Look into this one carefully. The COP for heat pumps are exaggerated compared to real conditions. Your climate sounds good for them but be careful. In Montana electricity prices have skyrocketed.
Boilers heat the thermal mass of your home. After 20 years I’m only now starting to understand this. If you used furnaces in the past you know that they heat the air not the mass of your house. Hot air works quickly, thermal mass is slow and steady but more efficient for me (possibly you.) Our boiler man has one in his home. He wouldn’t have anything else.
My wood burning fireplace is probably only 50-60% efficiency. It heats the living room and some upstairs bedrooms. Not the north side bedroom and not the lower floor. Windows and high ceiling are also expensive to heat. Still we love ours and we expect to pay for the joy Come to think of it, similar logic applies to our fireplace.
bradinsky
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Re: Is a heat pump the right choice for us?

Post by bradinsky »

Why not have a qualified company check & assess your current system? To me, that seems like the best place to start. We have 2 heat pumps in a 2550 sq. ft. home in northern Ohio & are very satisfied, but I’ve always heard that the most comfortable heating systems are well balanced hot water heat.
Gadget
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Re: Is a heat pump the right choice for us?

Post by Gadget »

twh wrote: Sun May 28, 2023 2:26 pm Few things...

I do not like Nest thermostats. Too much guessing going on. I know the schedule and I just want the schedule. I cannot imagine 13 zones on Nest -- that sounds like a nightmare all by itself and that is likely part of your problem.

If you do replace, you might want to consider dual-fuel systems. That way you can leverage the best price and if you need that extra jolt that hydrocarbon heating provides, you can leverage that as well.
This is not correct. You can setup Nest thermostats to a specific schedule. You don't have to use its auto climate feature (I don't).

In fact, with more zones it's even easier on a Nest. You can copy/paste schedules between thermostats and setup everything to switch from home to away temperatures just by your family phone locations. That way it's all just programmed schedule on, or eco saving temperatures on based on if you're home or not.
ncbill
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Re: Is a heat pump the right choice for us?

Post by ncbill »

Fire2020 wrote: Sun May 28, 2023 1:18 pm We are the new owners of a large (7,200 sqft) one of a kind house that is in need of new heating systems.

Currently we have two boilers that are about 20 years old (198,000 btu's each). They have probably never been serviced, seem to use ridiculous amounts of gas, and do a pathetic job heating certain parts of the house. Last winter we heated some rooms via the boilers, closed down some rooms and heated other areas with a wood burning stove. We went through about 2,500 gallons of propane, ten cords of hardwood and still had a cold house. Local temps in January vary from a high of 34 to a low of 15 degrees. February is 40 to 20, March is 50 to 30 etc. We have nest thermostats with 13 zones, so we know when the heat is cycling on and off.

We are potentially looking to replace at least one of the gas furnaces with a heat pump but would like to know what to expect as far as electricity usage.

Most of the house has decorative concrete floors with radiant in-floor heating. Other rooms have cast iron radiators. Not much passive solar to speak of in most of the house.

In general, the house is made of lots of real stone along with brick and wood on both the interior and exterior walls. We often have to open the windows to let in some heat this time of year when it's 64 inside and 70 outside.

That's a lot of information I know. I think we have a few problems contributing to our massive heating bill (old boilers, big house, thermal mass etc). We're hoping a heat pump will help a lot, but it's not cheap. The other option is just replace the boilers with new high efficiency boilers.
Big price difference $30K vs $18K per boiler, and we have two. We pay 10 cents a KWh off peak, 20 during peak. Propane is now $2.60 a gallon if you pre-buy.
Have you had an energy audit yet?

Blower door test, etc.

First thing I would look to is air sealing to prevent heat migrating to unconditioned space and if any extra insulation is warranted.
Teague
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Re: Is a heat pump the right choice for us?

Post by Teague »

ncbill wrote: Mon May 29, 2023 7:41 am
Fire2020 wrote: Sun May 28, 2023 1:18 pm We are the new owners of a large (7,200 sqft) one of a kind house that is in need of new heating systems.

Currently we have two boilers that are about 20 years old (198,000 btu's each). They have probably never been serviced, seem to use ridiculous amounts of gas, and do a pathetic job heating certain parts of the house. Last winter we heated some rooms via the boilers, closed down some rooms and heated other areas with a wood burning stove. We went through about 2,500 gallons of propane, ten cords of hardwood and still had a cold house. Local temps in January vary from a high of 34 to a low of 15 degrees. February is 40 to 20, March is 50 to 30 etc. We have nest thermostats with 13 zones, so we know when the heat is cycling on and off.

We are potentially looking to replace at least one of the gas furnaces with a heat pump but would like to know what to expect as far as electricity usage.

Most of the house has decorative concrete floors with radiant in-floor heating. Other rooms have cast iron radiators. Not much passive solar to speak of in most of the house.

In general, the house is made of lots of real stone along with brick and wood on both the interior and exterior walls. We often have to open the windows to let in some heat this time of year when it's 64 inside and 70 outside.

That's a lot of information I know. I think we have a few problems contributing to our massive heating bill (old boilers, big house, thermal mass etc). We're hoping a heat pump will help a lot, but it's not cheap. The other option is just replace the boilers with new high efficiency boilers.
Big price difference $30K vs $18K per boiler, and we have two. We pay 10 cents a KWh off peak, 20 during peak. Propane is now $2.60 a gallon if you pre-buy.
Have you had an energy audit yet?

Blower door test, etc.

First thing I would look to is air sealing to prevent heat migrating to unconditioned space and if any extra insulation is warranted.
For those who are unfamiliar with the benefits of a blower door test I share the following video: James Brown (yes, that James Brown, the Godfather of Soul) explaining the HVAC blower door in some detail. Odd but true. There are various hypotheses of how and why this video came to be, which I won't get into here. Anyway ladies and gents, let's hear it for The Godfather of Soul, James Brown!

https://www.youtube.com/watch?v=Xsp3yCxoYOA
Semper Augustus
Valuethinker
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Re: Is a heat pump the right choice for us?

Post by Valuethinker »

Fire2020 wrote: Sun May 28, 2023 1:18 pm We are the new owners of a large (7,200 sqft) one of a kind house that is in need of new heating systems.

Currently we have two boilers that are about 20 years old (198,000 btu's each). They have probably never been serviced, seem to use ridiculous amounts of gas, and do a pathetic job heating certain parts of the house.
New boilers will probably reduce consumption by 10-20% simply due to higher efficiency. HOWEVER the boilers are the wrong size so that has to be fixed as well.
Last winter we heated some rooms via the boilers, closed down some rooms and heated other areas with a wood burning stove. We went through about 2,500 gallons of propane, ten cords of hardwood and still had a cold house. Local temps in January vary from a high of 34 to a low of 15 degrees. February is 40 to 20, March is 50 to 30 etc. We have nest thermostats with 13 zones, so we know when the heat is cycling on and off.
Definitely needs to be looked at holistically via an energy audit and a "Manual J" calculation by a qualified engineer (which might not get the right answer because of the complexity).
We are potentially looking to replace at least one of the gas furnaces with a heat pump but would like to know what to expect as far as electricity usage.
Propane furnaces are not, I don't think, as efficient as natural gas ones. Figure 85% efficiency. Then a heat pump will be c 3-4x as efficient, depending on outside temperatures. There are, from memory, 3411 BTUs in a kwhr so you can convert your gas consumption to electricity kwhr and compare.

A viable strategy might be heat pump with a single propane furnace as backup.
Most of the house has decorative concrete floors with radiant in-floor heating. Other rooms have cast iron radiators. Not much passive solar to speak of in most of the house.

In general, the house is made of lots of real stone along with brick and wood on both the interior and exterior walls. We often have to open the windows to let in some heat this time of year when it's 64 inside and 70 outside.

That's a lot of information I know. I think we have a few problems contributing to our massive heating bill (old boilers, big house, thermal mass etc). We're hoping a heat pump will help a lot, but it's not cheap. The other option is just replace the boilers with new high efficiency boilers.
Big price difference $30K vs $18K per boiler, and we have two. We pay 10 cents a KWh off peak, 20 during peak. Propane is now $2.60 a gallon if you pre-buy.
ncbill wrote: Mon May 29, 2023 7:41 am Have you had an energy audit yet?

Blower door test, etc.

First thing I would look to is air sealing to prevent heat migrating to unconditioned space and if any extra insulation is warranted.
ncbill is absolutely right. The boilers are the wrong size, and the right size cannot be achieved without first knowing what the thermal profile of the house is.

It would be helpful to know which climatic zone OP is in. It sounds like the Northeastern USA, because that's where you find rad heaters?

It sounds like quite an old house. 1900 or earlier?

Poster Tomato Tomahto has a house in New England with a ground source (geothermal) heat pump system and is very happy. Huge house, and old.

(I live in an uninsulated Victorian house but in a relatively mild climate (London, England) where temperatures seldom go below freezing for long periods. We still have some original single pane glass, there's only insulation in the attic, etc. At some point legal changes will require that we move from a gas furnace to a heat pump. Both gas and electricity prices went up 300-400% with the Ukraine war crisis, and have not yet come back down fully. Heat with rads (as 90% British homes do).

So I am keeping an eye on the economics of heat pumps. They cost a lot more than a gas boiler. They seem to be able to cope with English winters, although the usage is different "low and slow" ie on all the time v "hard and fast" of a gas boiler (turn it down when you are not at home, up when you get home)).
Topic Author
Fire2020
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Re: Is a heat pump the right choice for us?

Post by Fire2020 »

Thanks for the replies everyone!

We've had three different HVAC companies give their opinion on our heating issues. The first company said we had a gas leak. Thankfully, we didn't. The second company said we needed to replace both circulation pumps and that would fix the issue. It didn't. The third company said it was likely air in the heating lines, but when they saw the system, there was no way to isolate the individual loops to purge the air. They could install a manifold to isolate the loops, but said the boilers just needed replacing anyway given their old age and subsequently limited efficiency and recommended heat pumps. Unfortunately, some of the heat pump data we were given by this company was incorrect when we started researching it. They acknowledged that they have limited experience actually installing heat pumps. We'll keep trying to find a local provider who has experience installing heat pumps and/or geothermal systems, as obviously, this isn't a DIY project.

A home energy audit is a good idea, and we are trying to tackle this ourselves. We bought a thermal imaging camera to make sure the heat is circulating through all of the loops of the floor heating. It seems to be working, but takes forever to get any heat into the floor. We also fixed several leaking air issues. I'm confident there are still areas that we can improve, but overall we think need to tackle the bigger boiler problem. The house is only 20 years old, but was built to look like it had been constructed in the 1800's. It has an insane amount of doors and windows and it's 85% single story. IIRC it has about 30 doors that open directly to the outside. All these doors and windows are super high end and have double pane glass and weather stripping to seal them from drafts. To put things in perspective, the premier of the house is about 630ft or 0.12 miles. :shock:

Thanks for the link to the heatinghelp forum. I'll check this site out.

I will also look into the "Manual J" calculation.

It was also mentioned a few times that the boilers were the wrong size? Are the under or over sized?
LotsaGray
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Re: Is a heat pump the right choice for us?

Post by LotsaGray »

I did not see it mentioned but where do you live? What is the winter climate?

I know people will tell you that heat pumps work anywhere and they were designed based on a Chicago winter. That is plain BS. They do not work well when temps fall below upper 20’s.

I have a heat pump now and live along gulf coast. It works great though back in December we were cold enough that the back up electric resistance had to take over. That is not common weather for here.

Also had a heat pump when I lived near Poconos in PA. There it was marginal at best.

Making a rough guess for you, I would guess new HE boilers would be a better choice but I am not an expert and working with limited data.
bradinsky
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Re: Is a heat pump the right choice for us?

Post by bradinsky »

Did you have a company that specializes in boilers do an inspection, or just a run of the mill HVAC company? I would trust their opinion more than others.
rich126
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Re: Is a heat pump the right choice for us?

Post by rich126 »

LotsaGray wrote: Mon May 29, 2023 3:31 pm I did not see it mentioned but where do you live? What is the winter climate?

I know people will tell you that heat pumps work anywhere and they were designed based on a Chicago winter. That is plain BS. They do not work well when temps fall below upper 20’s.

I have a heat pump now and live along gulf coast. It works great though back in December we were cold enough that the back up electric resistance had to take over. That is not common weather for here.

Also had a heat pump when I lived near Poconos in PA. There it was marginal at best.

Making a rough guess for you, I would guess new HE boilers would be a better choice but I am not an expert and working with limited data.
I've had heat pumps in townhouses and houses and your comment about heat pumps and cold weather is true in my experience. I lived mostly in Maryland so we don't get a low of very cold weather, the avg low in the winter is probably mid to upper 30s so heat pumps are usually ok. When it did get very cold, they often use some kind of resistance auxiliary heating which is very inefficient and costly.
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bradinsky
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Re: Is a heat pump the right choice for us?

Post by bradinsky »

LotsaGray wrote: Mon May 29, 2023 3:31 pm I did not see it mentioned but where do you live? What is the winter climate?

I know people will tell you that heat pumps work anywhere and they were designed based on a Chicago winter. That is plain BS. They do not work well when temps fall below upper 20’s.

I have a heat pump now and live along gulf coast. It works great though back in December we were cold enough that the back up electric resistance had to take over. That is not common weather for here.

Also had a heat pump when I lived near Poconos in PA. There it was marginal at best.

Making a rough guess for you, I would guess new HE boilers would be a better choice but I am not an expert and working with limited data.
We live in northern Ohio & our heat pumps work fine. The newest is a Bosch inverter unit. FWIW, it gets plenty cold here in the winter.
talzara
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Re: Is a heat pump the right choice for us?

Post by talzara »

Fire2020 wrote: Mon May 29, 2023 1:53 pm We've had three different HVAC companies give their opinion on our heating issues. The first company said we had a gas leak. Thankfully, we didn't. The second company said we needed to replace both circulation pumps and that would fix the issue. It didn't. The third company said it was likely air in the heating lines, but when they saw the system, there was no way to isolate the individual loops to purge the air. They could install a manifold to isolate the loops, but said the boilers just needed replacing anyway given their old age and subsequently limited efficiency and recommended heat pumps.
Get the manifold installed first, and purge the air from the system.

How do they know the boilers are inefficient? Did they do a combustion analysis?

The residential HVAC industry in the United States likes to install new equipment. Their recommended solution to every problem is to replace the system. There are several air conditioner threads on Bogleheads every summer where the HVAC technician recommends a new system for $10,000 when it's just a bad capacitor. We tell them to call a different HVAC company and get the capacitor replaced for $300.

The way to fix problems is to fix problems. Don't install new equipment until you've already fixed the problems and still need better performance.
Fire2020 wrote: Mon May 29, 2023 1:53 pm A home energy audit is a good idea, and we are trying to tackle this ourselves. We bought a thermal imaging camera to make sure the heat is circulating through all of the loops of the floor heating. It seems to be working, but takes forever to get any heat into the floor.
You should hire a professional. You need numbers, not just "it takes forever." What's the temperature rise? What's the flow rate? How much heat is being given off by the radiant floors, and how much heat is being lost? There's a reason that the room is cold. Find that reason and fix that problem.

Also, this is a custom house that was only built 20 years ago. Can you locate the original owners? Do they have the original HVAC system design or the Manual J report? The Manual J calculation is supposed to be done before the system is installed. Doing it later will require some guesswork. If no Manual J was ever done, then that is also useful to know.
talzara
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Re: Is a heat pump the right choice for us?

Post by talzara »

LotsaGray wrote: Mon May 29, 2023 3:31 pm I know people will tell you that heat pumps work anywhere and they were designed based on a Chicago winter. That is plain BS. They do not work well when temps fall below upper 20’s.

I have a heat pump now and live along gulf coast. It works great though back in December we were cold enough that the back up electric resistance had to take over. That is not common weather for here.

Also had a heat pump when I lived near Poconos in PA. There it was marginal at best.
This is a common misconception that comes up a lot in heat pump threads.

American heat pumps are designed for cooling and run in reverse for heating. They achieve their rated capacity at 47°F, and they lose capacity below that temperature.

Asian heat pumps are designed for heating and run in reverse for cooling. The high-temperature models can achieve 100% of rated capacity at 17°F, and the low-temperature models can maintain capacity down to 5°F or even 0°F.

The American residential HVAC industry is farther behind than the Detroit automakers were in 1980. If you say that heat pumps don't work below "upper 20’s" based on experience with American heat pumps, that's like saying that you don't want to buy a 1983 Toyota Corolla because you had a bad experience with a 1978 Ford Pinto.

Half of the homes in Norway are heated by heat pumps. The design temperature in Oslo is only 2°F above the design temperature in Chicago. If heat pumps can work in Oslo, then they can work in Chicago and the Poconos, Pennsylvania.

Oslo is in southern Norway, and Chicago is in the northern United States. A warm climate for them is a cold climate for us. If heat pumps can work in Norway, then they can work in almost all of the United States.
rich126 wrote: Mon May 29, 2023 3:40 pm I've had heat pumps in townhouses and houses and your comment about heat pumps and cold weather is true in my experience. I lived mostly in Maryland so we don't get a low of very cold weather, the avg low in the winter is probably mid to upper 30s so heat pumps are usually ok. When it did get very cold, they often use some kind of resistance auxiliary heating which is very inefficient and costly.
Oslo is colder than Maryland. If heat pumps can work in Oslo, then they can work in Maryland.
talzara
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Re: Is a heat pump the right choice for us?

Post by talzara »

beardsicles wrote: Sun May 28, 2023 3:57 pm
Designairohio wrote: Sun May 28, 2023 3:01 pm Is it even possible to add the ductwork you would need for the heat pump?
You can, within reason. We did partially ducted heat pump in a floor of our house. But nothing on the scale of OP’s house. Given the scale, the solution is almost certainly geothermal heat pumps. Especially given the substantial tax credit.
Carl53 wrote: Sun May 28, 2023 5:45 pm Prior home had an ground source heat pump that heated/cooled (water to air) as well as heated the hot water (water to water) and pool (water to water) but ultimately became a problem when the foreign manufacturer went out of business and I needed a replacement heat exchanger.
Air-to-water heat pumps will have a lower installed cost than ground source heat pumps. They're less efficient, but avoiding the cost of drilling could save you more money than the increased operational cost.

There are millions of air-to-water heat pumps in Asia and Europe, but they're hard to find in the United States. However, things are starting to look up. Johnson Controls-Hitachi recently announced that they will be bringing the Hitachi Yutaki M air-to-water heat pump to the United States. SpacePak is already importing one and putting its own label on the SpacePak Solstice.

It's not a coincidence that Hitachi is finally bringing an air-to-water heat pump to the United States. New York City has banned fossil fuel hookups in new construction effective January 1, 2024. Anyone who wants radiant heat in a new building will be considering air-to-water heat pumps for the first time. Hitachi wants to have the equipment in warehouses by the end of the year, ready to ship to contractors in New York City.

That's why the OP should try to get the existing system fixed. Do you want to install a niche product that a few thousand customers, or do you want to install a unit from a major multinational HVAC manufacturer that has millions of customers? It's worth it to fix the system and make it last a few more years. New products will be available soon, as soon as next year if you live near New York City.
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Re: Is a heat pump the right choice for us?

Post by LotsaGray »

talzara wrote: Mon May 29, 2023 5:51 pm
LotsaGray wrote: Mon May 29, 2023 3:31 pm I know people will tell you that heat pumps work anywhere and they were designed based on a Chicago winter. That is plain BS. They do not work well when temps fall below upper 20’s.

I have a heat pump now and live along gulf coast. It works great though back in December we were cold enough that the back up electric resistance had to take over. That is not common weather for here.

Also had a heat pump when I lived near Poconos in PA. There it was marginal at best.
This is a common misconception that comes up a lot in heat pump threads.

American heat pumps are designed for cooling and run in reverse for heating. They achieve their rated capacity at 47°F, and they lose capacity below that temperature.

Asian heat pumps are designed for heating and run in reverse for cooling. The high-temperature models can achieve 100% of rated capacity at 17°F, and the low-temperature models can maintain capacity down to 5°F or even 0°F.

The American residential HVAC industry is farther behind than the Detroit automakers were in 1980. If you say that heat pumps don't work below "upper 20’s" based on experience with American heat pumps, that's like saying that you don't want to buy a 1983 Toyota Corolla because you had a bad experience with a 1978 Ford Pinto.

Half of the homes in Norway are heated by heat pumps. The design temperature in Oslo is only 2°F above the design temperature in Chicago. If heat pumps can work in Oslo, then they can work in Chicago and the Poconos, Pennsylvania.

Oslo is in southern Norway, and Chicago is in the northern United States. A warm climate for them is a cold climate for us. If heat pumps can work in Norway, then they can work in almost all of the United States.
rich126 wrote: Mon May 29, 2023 3:40 pm I've had heat pumps in townhouses and houses and your comment about heat pumps and cold weather is true in my experience. I lived mostly in Maryland so we don't get a low of very cold weather, the avg low in the winter is probably mid to upper 30s so heat pumps are usually ok. When it did get very cold, they often use some kind of resistance auxiliary heating which is very inefficient and costly.
Oslo is colder than Maryland. If heat pumps can work in Oslo, then they can work in Maryland.
Note I did not say HO did not work below upper 20’s. I said they do not work well. And while I don’t know anything about HP in Japan, that you used that design as a reference de facto confirms what I said. Fact is OP is in USA and if he were to install a HP it will almost definitely be one designed for US.

Be very careful talking climate between Midwest US and Europe. What you discussed may be true for Norway and maybe Sweden but for a given lattitude Europe climate much warmer than Midwest US due to the Gulf Stream.

Heat pumps don’t run in reverse they expand the fluid at a different point in the circuit. The expansion occurs after the evaporator (which makes that name a misnomer). I fully agree that design changes can improve the heating performance of a HP but that isn’t what OP is likely to get.
Hayward
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Re: Is a heat pump the right choice for us?

Post by Hayward »

Do post your questions on heatinghelp.com. A modern modulating and condensing gas boiler with the proper controls should be efficient, and it is unlikely that a heat pump would provide the same degree of comfort (or quiet, indoors or out).
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Re: Is a heat pump the right choice for us?

Post by spth »

400,000 BTUs for 7500sf? Just a comparison, I live in a colder climate and have a 100,000 BTU boiler for 4000sf and it’s usually running at 25%. It’s kept up with -20f without any issues.

Most of your issue would likely be solved with insulation.

Boilers are pretty simple. Someone might need to drill out any corroded gas holes in the burners and help with your expansion tank set up. I doubt they are toast.

You would need lots of wells for that many BTUs of geothermal.

You will also have issues with the in floor heat and radiators. They likely run at different temps. I assume this might be why you have two boilers.

The geothermal can heat the water to 125F so for the radiators you’ll need to augment that on the coldest days. Your existing boiler should be able to do that. The in-floor heat should be fine with that temp.


I just read your last post. Do you know the layout of the system? Was the in floor heat added later? Might the hot water go through the radiators first and then through the floor?

I don’t have as much house as you do, but I had similar issues. Every HVAC person I spoke with didn’t really know that much or told me I couldn’t do what I wanted to do. I ended up replacing the entire system myself. The best thing I did was add mechanical thermostats to each radiator that open and close based at the room temp. They work great, are low cost and require no electricity.
Last edited by spth on Mon May 29, 2023 11:14 pm, edited 1 time in total.
will86
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Re: Is a heat pump the right choice for us?

Post by will86 »

They could install a manifold to isolate the loops, but said the boilers just needed replacing anyway given their old age and subsequently limited efficiency and recommended heat pumps.
no existing manifolds?, possibly a sub optimal install of the in slab piping?
does the proposed heatpump call for ducts?


find someone who can test the adequacy of the embedded piping
if the runs are inadequate, ie, not properly insulated below, too long (or other excessive pressure drop), spaced too far apart, or otherwise have too much temprature differential to work well, then another heat delivery system must be considered and priced before decisions about heat sources will be useful
Last edited by will86 on Tue May 30, 2023 11:45 am, edited 1 time in total.
Valuethinker
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Re: Is a heat pump the right choice for us?

Post by Valuethinker »

Hayward wrote: Mon May 29, 2023 10:26 pm Do post your questions on heatinghelp.com. A modern modulating and condensing gas boiler with the proper controls should be efficient, and it is unlikely that a heat pump would provide the same degree of comfort (or quiet, indoors or out).
OP is on propane though. That makes the calculations a little different?

Basically higher cost per unit energy than natural gas, most of the time, most places in North America?

Heat Pumps can do the job, they just do it differently. For example with a radiant heating floor, one just runs the HP all the time at the desired temperature.
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Re: Is a heat pump the right choice for us?

Post by mrc »

talzara wrote: Mon May 29, 2023 5:51 pm Oslo is in southern Norway, and Chicago is in the northern United States. A warm climate for them is a cold climate for us. If heat pumps can work in Norway, then they can work in almost all of the United States.
For the record, average low temps in winter are colder in Chicago than Oslo, by a couple degrees. Minimum temp might factor in here too given the type of auxiliary heat available.

Chicago ave min 20

Oslo ave min 23
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hand
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Re: Is a heat pump the right choice for us?

Post by hand »

LotsaGray wrote: Mon May 29, 2023 3:31 pm I did not see it mentioned but where do you live? What is the winter climate?

I know people will tell you that heat pumps work anywhere and they were designed based on a Chicago winter. That is plain BS. They do not work well when temps fall below upper 20’s.

I have a heat pump now and live along gulf coast. It works great though back in December we were cold enough that the back up electric resistance had to take over. That is not common weather for here.

Also had a heat pump when I lived near Poconos in PA. There it was marginal at best.

Making a rough guess for you, I would guess new HE boilers would be a better choice but I am not an expert and working with limited data.
This information feels a generation or two out dated - I cross-shopped Mitsubishi Hyper-Heat and Samsung Max Heat which both marketed heat production to -13F degrees.

Digging into the details, the Mitsubishi was able to produce 100% rated heat down to 5F degrees and 85% rated heat into the negative teens.

I've been very happy with my heat pump in the NorthEast, and especially pleased with the cost efficiency.
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Re: Is a heat pump the right choice for us?

Post by TomatoTomahto »

spth wrote: Mon May 29, 2023 10:51 pm
You would need lots of wells for that many BTUs of geothermal.
Depending on where OP lives, horizontal wells might be an option. Near Boston, that was a non-starter for us (in addition to the smiles I got when asking the question, I watched what the drill brought up after a few feet, and could have answered the question myself).

Since OP says they have a lot of stone in their house, I’m assuming that their land is probably very stony (ledge) and vertical drilling is required. That isn’t necessarily a deal breaker, but it does add to the cost. Otoh, we drilled 5 wells (200’ each for 2,000’ of combined depth) in a very small horizontal area and it hasn’t affected the appearance of the land at all.

As OP has learned, or will learn, the only thing fieldstone insulates against is wifi :oops: . It does have thermal mass though, and will eventually heat up or cool down.

The initial cost of a ground based heat pump is high, but running costs are very low. The government and utility paid for, iirc, approximately 40% of the cost and also offered an interest free 7 year loan. We didn’t take advantage of the loan when interest rates were effectively zero; unlucky in retrospect, but the loan had to be applied for before work commenced and we did not want to wait.

ETA: I looked up my numbers, and even without the loan, various incentives covered 45% of the cost in Massachusetts.
I get the FI part but not the RE part of FIRE.
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Re: Is a heat pump the right choice for us?

Post by THY4373 »

LotsaGray wrote: Mon May 29, 2023 10:06 pm
Note I did not say HO did not work below upper 20’s. I said they do not work well. And while I don’t know anything about HP in Japan, that you used that design as a reference de facto confirms what I said. Fact is OP is in USA and if he were to install a HP it will almost definitely be one designed for US.
Asian heat pumps are widely available in the US. Yes they are speced for the US but they also have the performance. I installed a Mitsubishi ducted unit to replace the upstairs heat pump in my house. The outside unit is made in a Japan and is essentially a condenser unit from a mini-split system. The inside ducted unit was designed and built in North America. I needed a 1.5 ton unit (small upstairs) and for the price of a US built two stage system I could get a full inverter system from Mitsubishi. Mitsubishi does not make their hyper heat (low temperature heat pumps) in a 1.5 ton unit so I have their "regular" unit. Even so the heat pump is capable of putting out 70% of its rated capacity down to 5 degrees F at a COP of 3.15 (so still plenty efficient). I am in the mid-Atlantic area so it is fairly rare to get that low. The 1.5 ton was probably already over speced for the area I need to heat and cool so I went with a 1.5 ton and backup resistance strips (versus upsizing to get hyper heat). When I get around to replacing the downstairs I'll for sure get a hyper heat (or similar spec from another manufacturer) system since I'll need a 2.5 ton there give or take (need to do load calculations).

I will say the Mitsubishi is amazing. When standing next to the condenser outside I can barely hear it. If my neighbor's old school US single speed heat pumps are running they drown out my Mitsubishi completely. I cannot comment on the high-end US stuff (I didn't research it because they didn't make in a 1.5 ton spec) but in my experience and research the Asian's have trounced the performance of the entry and mid-level stuff. In fact my Mitsubishi is a commercial "P" unit which is intended to run in commercial applications such a data centers (I can run it in cooling mode below freezing outside not that I would ever want to) and that was the same price as a US made two speed system. It is a much better system however you look at it for the price.
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Re: Is a heat pump the right choice for us?

Post by Theseus »

THY4373 wrote: Tue May 30, 2023 8:33 am
LotsaGray wrote: Mon May 29, 2023 10:06 pm
Note I did not say HO did not work below upper 20’s. I said they do not work well. And while I don’t know anything about HP in Japan, that you used that design as a reference de facto confirms what I said. Fact is OP is in USA and if he were to install a HP it will almost definitely be one designed for US.
Asian heat pumps are widely available in the US. Yes they are speced for the US but they also have the performance. I installed a Mitsubishi ducted unit to replace the upstairs heat pump in my house. The outside unit is made in a Japan and is essentially a condenser unit from a mini-split system. The inside ducted unit was designed and built in North America. I needed a 1.5 ton unit (small upstairs) and for the price of a US built two stage system I could get a full inverter system from Mitsubishi. Mitsubishi does not make their hyper heat (low temperature heat pumps) in a 1.5 ton unit so I have their "regular" unit. Even so the heat pump is capable of putting out 70% of its rated capacity down to 5 degrees F at a COP of 3.15 (so still plenty efficient). I am in the mid-Atlantic area so it is fairly rare to get that low. The 1.5 ton was probably already over speced for the area I need to heat and cool so I went with a 1.5 ton and backup resistance strips (versus upsizing to get hyper heat). When I get around to replacing the downstairs I'll for sure get a hyper heat (or similar spec from another manufacturer) system since I'll need a 2.5 ton there give or take (need to do load calculations).

I will say the Mitsubishi is amazing. When standing next to the condenser outside I can barely hear it. If my neighbor's old school US single speed heat pumps are running they drown out my Mitsubishi completely. I cannot comment on the high-end US stuff (I didn't research it because they didn't make in a 1.5 ton spec) but in my experience and research the Asian's have trounced the performance of the entry and mid-level stuff. In fact my Mitsubishi is a commercial "P" unit which is intended to run in commercial applications such a data centers (I can run it in cooling mode below freezing outside not that I would ever want to) and that was the same price as a US made two speed system. It is a much better system however you look at it for the price.
This is a very interesting post. Thank you for the detailed information. My heatpump is 18 years old and it is highly likely I will need a new one in next 0-3 years. So I have ben following threads related to that.

In this forum when people talk about heat pump install, they always say that the installer makes a bigger difference than the brand of the unit. I am not sure how it is to install Mitsubishi or Samsung, but how did you go about finding a reliable installer?

Also what is an inverter system (I know I can google it but thought you might have a direct and simple explanation).
Valuethinker
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Re: Is a heat pump the right choice for us?

Post by Valuethinker »

Theseus wrote: Tue May 30, 2023 9:58 am
THY4373 wrote: Tue May 30, 2023 8:33 am
LotsaGray wrote: Mon May 29, 2023 10:06 pm
Note I did not say HO did not work below upper 20’s. I said they do not work well. And while I don’t know anything about HP in Japan, that you used that design as a reference de facto confirms what I said. Fact is OP is in USA and if he were to install a HP it will almost definitely be one designed for US.
Asian heat pumps are widely available in the US. Yes they are speced for the US but they also have the performance. I installed a Mitsubishi ducted unit to replace the upstairs heat pump in my house. The outside unit is made in a Japan and is essentially a condenser unit from a mini-split system. The inside ducted unit was designed and built in North America. I needed a 1.5 ton unit (small upstairs) and for the price of a US built two stage system I could get a full inverter system from Mitsubishi. Mitsubishi does not make their hyper heat (low temperature heat pumps) in a 1.5 ton unit so I have their "regular" unit. Even so the heat pump is capable of putting out 70% of its rated capacity down to 5 degrees F at a COP of 3.15 (so still plenty efficient). I am in the mid-Atlantic area so it is fairly rare to get that low. The 1.5 ton was probably already over speced for the area I need to heat and cool so I went with a 1.5 ton and backup resistance strips (versus upsizing to get hyper heat). When I get around to replacing the downstairs I'll for sure get a hyper heat (or similar spec from another manufacturer) system since I'll need a 2.5 ton there give or take (need to do load calculations).

I will say the Mitsubishi is amazing. When standing next to the condenser outside I can barely hear it. If my neighbor's old school US single speed heat pumps are running they drown out my Mitsubishi completely. I cannot comment on the high-end US stuff (I didn't research it because they didn't make in a 1.5 ton spec) but in my experience and research the Asian's have trounced the performance of the entry and mid-level stuff. In fact my Mitsubishi is a commercial "P" unit which is intended to run in commercial applications such a data centers (I can run it in cooling mode below freezing outside not that I would ever want to) and that was the same price as a US made two speed system. It is a much better system however you look at it for the price.
This is a very interesting post. Thank you for the detailed information. My heatpump is 18 years old and it is highly likely I will need a new one in next 0-3 years. So I have ben following threads related to that.

In this forum when people talk about heat pump install, they always say that the installer makes a bigger difference than the brand of the unit. I am not sure how it is to install Mitsubishi or Samsung, but how did you go about finding a reliable installer?
The Japanese manufacturers dominate. Not sure about the Koreans?
Also what is an inverter system (I know I can google it but thought you might have a direct and simple explanation).
I think inverter means that the system uses a variable speed electric motor. I.e. not 1-speed or 2-speed but as many speeds as needed within a range.
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Re: Is a heat pump the right choice for us?

Post by THY4373 »

Theseus wrote: Tue May 30, 2023 9:58 am
This is a very interesting post. Thank you for the detailed information. My heatpump is 18 years old and it is highly likely I will need a new one in next 0-3 years. So I have ben following threads related to that.

In this forum when people talk about heat pump install, they always say that the installer makes a bigger difference than the brand of the unit. I am not sure how it is to install Mitsubishi or Samsung, but how did you go about finding a reliable installer?

Also what is an inverter system (I know I can google it but thought you might have a direct and simple explanation).
My upstairs heat pump was 30-31 years old when it was replaced and to its (and Trane's) credit was still running fine. Put simply an inverter system is capable of running anywhere between say 30-40% to 100% of capacity. It is able to spin up and down the speed of the compressor and fan as needed. My system runs well below maximum most of the time which increases efficiency and reduces cycling. It also allows for more even cooling and heating. Most traditional systems are one speed 100% or two speed usually something like a fixed 65-75% or 100%. The negative of the inverter systems is they have a lot more electronics so you probably want some sort of surge suppressor on them and/or on your house. The Asian manufacturers have been doing inverter systems at mass scale longer than the US manufacturers.

As for manufacturer not mattering I'd say that is something of an over simplification. For example most American manufacturers make some different grades of equipment under different names. Also you want to be sure your manufacture is going to support your system for some time and this is probably more of a concern with some of the Asian manufacturers who aren't big in the US (particularly the Chinese manufactuers).

For my upstairs system after I had eliminated the US brands I focused on Mitsubishi, Fujitsu, and Daiken as the higher end Asian brands with good support. Locally I found Mitsubishi had far more installers than the other two so I went with them. How I found installers was look at the manufacturers website for certified installers in my area and then researched reviews online and got five estimates.
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Re: Is a heat pump the right choice for us?

Post by THY4373 »

Valuethinker wrote: Tue May 30, 2023 10:42 am
The Japanese manufacturers dominate. Not sure about the Koreans?
Some Korean stuff and also a fair amount of Chinese stuff. Carrier is selling mini-splits that are manufactured by one of the larger Chinese manufacturers that I think Carrier may have bought out. A lot of the US carriers are now buying/partnering with Asian manufacturers. My Mitsubishi is actually marketed by Trane.
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Re: Is a heat pump the right choice for us?

Post by alfaspider »

Just a note on American vs. Asian heat pumps. Many HVAC brands are still selling dated heat pump units, but the higher end models have caught up. I recently had a Carrier Infinity heat pump installed, which advertises performance down to -15*F. Granted, I will never need to test that in my climate, but it's similar spec to the Asian mini split I use in my garage.

It is true that a lot of people's perception of heat pumps has been colored by 20 year old designs that were inefficient and only suitable for very mild climates.
Last edited by alfaspider on Tue May 30, 2023 11:10 am, edited 1 time in total.
alfaspider
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Re: Is a heat pump the right choice for us?

Post by alfaspider »

Theseus wrote: Tue May 30, 2023 9:58 am
THY4373 wrote: Tue May 30, 2023 8:33 am
LotsaGray wrote: Mon May 29, 2023 10:06 pm
Note I did not say HO did not work below upper 20’s. I said they do not work well. And while I don’t know anything about HP in Japan, that you used that design as a reference de facto confirms what I said. Fact is OP is in USA and if he were to install a HP it will almost definitely be one designed for US.
Asian heat pumps are widely available in the US. Yes they are speced for the US but they also have the performance. I installed a Mitsubishi ducted unit to replace the upstairs heat pump in my house. The outside unit is made in a Japan and is essentially a condenser unit from a mini-split system. The inside ducted unit was designed and built in North America. I needed a 1.5 ton unit (small upstairs) and for the price of a US built two stage system I could get a full inverter system from Mitsubishi. Mitsubishi does not make their hyper heat (low temperature heat pumps) in a 1.5 ton unit so I have their "regular" unit. Even so the heat pump is capable of putting out 70% of its rated capacity down to 5 degrees F at a COP of 3.15 (so still plenty efficient). I am in the mid-Atlantic area so it is fairly rare to get that low. The 1.5 ton was probably already over speced for the area I need to heat and cool so I went with a 1.5 ton and backup resistance strips (versus upsizing to get hyper heat). When I get around to replacing the downstairs I'll for sure get a hyper heat (or similar spec from another manufacturer) system since I'll need a 2.5 ton there give or take (need to do load calculations).

I will say the Mitsubishi is amazing. When standing next to the condenser outside I can barely hear it. If my neighbor's old school US single speed heat pumps are running they drown out my Mitsubishi completely. I cannot comment on the high-end US stuff (I didn't research it because they didn't make in a 1.5 ton spec) but in my experience and research the Asian's have trounced the performance of the entry and mid-level stuff. In fact my Mitsubishi is a commercial "P" unit which is intended to run in commercial applications such a data centers (I can run it in cooling mode below freezing outside not that I would ever want to) and that was the same price as a US made two speed system. It is a much better system however you look at it for the price.
This is a very interesting post. Thank you for the detailed information. My heatpump is 18 years old and it is highly likely I will need a new one in next 0-3 years. So I have ben following threads related to that.

In this forum when people talk about heat pump install, they always say that the installer makes a bigger difference than the brand of the unit. I am not sure how it is to install Mitsubishi or Samsung, but how did you go about finding a reliable installer?

Also what is an inverter system (I know I can google it but thought you might have a direct and simple explanation).
It's not as simple as brand-vs brand. Most major brands of ducted heat pumps make at least three grades of unit. Usually, there's a basic on/off single speed unit, a mid-grade two speed unit, and a higher end variable unit.

I don't think the install matters merely that much PROVIDED it's a competent install. Yes, if you have a poor quality install with obstructed ducting and a leaky line set, even the best HVAC unit will perform poorly. But once you get past the bar of basic competence, minor details in the install aren't going to matter as much as the quality of the unit.
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Re: Is a heat pump the right choice for us?

Post by THY4373 »

alfaspider wrote: Tue May 30, 2023 11:04 am Just a note on American vs. Asian heat pumps. Many HVAC brands are still selling dated heat pump units, but the higher end models have caught up. I recently had a Carrier Infinity heat pump installed, which advertises performance down to -15*F. Granted, I will never need to test that in my climate, but it's similar spec to the Asian mini split I use in my garage.

It is true that a lot of people's perception of heat pumps has been colored by 20 year old designs that were inefficient and only suitable for very mild climates.
This is true but the US high end equipment at least in my pricing is more expensive than the high end Asian stuff.
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hand
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Re: Is a heat pump the right choice for us?

Post by hand »

THY4373 wrote: Tue May 30, 2023 10:55 am
Valuethinker wrote: Tue May 30, 2023 10:42 am
The Japanese manufacturers dominate. Not sure about the Koreans?
Some Korean stuff and also a fair amount of Chinese stuff. Carrier is selling mini-splits that are manufactured by one of the larger Chinese manufacturers that I think Carrier may have bought out. A lot of the US carriers are now buying/partnering with Asian manufacturers. My Mitsubishi is actually marketed by Trane.
Both Carrier and Samsung appear to rebrand mini-splits manufactured by Midea a Chinese manufacturer.

Mitsubishi has generally been reported to be the gold standard (at a premium), but other manufacturers are often said to be more than sufficient with install brand decisions made based on hardware availability and installer quality.

One of the big differentiators between Mitsubishi and others when I looked at this was inclusion of onboard surge suppression - a difference easily rectified by adding surge (and low voltage) protection inline with the install.
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Re: Is a heat pump the right choice for us?

Post by leeks »

Fire2020 wrote: Mon May 29, 2023 1:53 pm Thanks for the replies everyone!

We've had three different HVAC companies give their opinion on our heating issues. The first company said we had a gas leak. Thankfully, we didn't. The second company said we needed to replace both circulation pumps and that would fix the issue. It didn't. The third company said it was likely air in the heating lines, but when they saw the system, there was no way to isolate the individual loops to purge the air. They could install a manifold to isolate the loops, but said the boilers just needed replacing anyway given their old age and subsequently limited efficiency and recommended heat pumps. Unfortunately, some of the heat pump data we were given by this company was incorrect when we started researching it. They acknowledged that they have limited experience actually installing heat pumps. We'll keep trying to find a local provider who has experience installing heat pumps and/or geothermal systems, as obviously, this isn't a DIY project.

A home energy audit is a good idea, and we are trying to tackle this ourselves. We bought a thermal imaging camera to make sure the heat is circulating through all of the loops of the floor heating. It seems to be working, but takes forever to get any heat into the floor. We also fixed several leaking air issues. I'm confident there are still areas that we can improve, but overall we think need to tackle the bigger boiler problem. The house is only 20 years old, but was built to look like it had been constructed in the 1800's. It has an insane amount of doors and windows and it's 85% single story. IIRC it has about 30 doors that open directly to the outside. All these doors and windows are super high end and have double pane glass and weather stripping to seal them from drafts. To put things in perspective, the premier of the house is about 630ft or 0.12 miles. :shock:

Thanks for the link to the heatinghelp forum. I'll check this site out.

I will also look into the "Manual J" calculation.

It was also mentioned a few times that the boilers were the wrong size? Are the under or over sized?
You have not found a real expert yet. I'm sorry your local companies have been of such little help. Keep looking for someone more knowledgeable and qualified to help you. Perhaps you need to look for a company from your nearest large metro area to find better expertise? Call and ask to talk to the owner or a senior person to see how they handle your questions before sending someone to look in person. And/or if your neighbors have giant old mansions too, talk to them to see what they have done with their homes and if they can recommend someone qualified enough to help you.

Another thought, do you have any historic estates in your area? The kind of old mansions that are preserved and open for tours/events? Maybe call some of those and see if their maintenance people will tell you what HVAC company they use.
ondarvr
Posts: 415
Joined: Tue Dec 22, 2020 5:03 pm

Re: Is a heat pump the right choice for us?

Post by ondarvr »

First.....listen to Talzara!!!

I've done a great deal of research on this subject and Talzara is about the most knowledgeable, informed and reliable source of information I've found anywhere.

This thread has taken the same path as many others on this site, not to mention every other site it comes up on. Somebody is looking for a new heating and cooling system and people relate their anecdotal evidence of thirty year old systems that use sixty year old technology about heat pumps to show they don't work.

While the US sat around and was satisfied with dated technology the rest of world made huge advances. This came about because our fossil fuels were relatively cheap, it didn't pay to ugrade, but that is changing rapidly, and the HVAC industry in the US is being "forced" to change too.

It's better than when I installed my system several years ago, but HVAC contractors are slow to change and keep up with the current technology. I was not able to find a company that fully understood mini splits, or the technology in general, and if they gave you a bid the cost was obscenely high.

You need to get a very knowledgeable person or company to evaluate your unique situation, not the average HVAC contractor.

And to all those that think heat pumps don't work well below 30F, think again. My system heats my house to a very comfortable 70+ when it's -10 outside. And a hint, I didn't go with the system design the contractors submitted, it was more inline with Talzara's recommendations, but I didn't find him until after I installed mine, I wish I had. My system works great, but he as knowledge of equipment and designs that would have helped me in choosing a brand to go with. Back then there were fewer players in the market, now they're common.
talzara
Posts: 4745
Joined: Thu Feb 12, 2009 6:40 pm

Re: Is a heat pump the right choice for us?

Post by talzara »

LotsaGray wrote: Mon May 29, 2023 10:06 pm Note I did not say HO did not work below upper 20’s. I said they do not work well. And while I don’t know anything about HP in Japan, that you used that design as a reference de facto confirms what I said. Fact is OP is in USA and if he were to install a HP it will almost definitely be one designed for US.
They can deliver 100% of rated capacity at 5°F or even 0°F. That doesn't work well enough for you?

Asian heat pumps are designed for the world. That's why they've been successful worldwide, including the United States. In the Northeast, 24% of heat pumps are mini-splits. In New England, it's 44%. That's just mini-splits. A Mitsubishi ducted unit would not get counted in the mini-split statistics. It's also installed base, not market share. The majority of heat pumps being installed in New England are Asian mini-splits.

The OP should not install a heat pump that was "designed for US." Install a heat pump that actually works at low temperatures.
LotsaGray wrote: Mon May 29, 2023 10:06 pm Be very careful talking climate between Midwest US and Europe. What you discussed may be true for Norway and maybe Sweden but for a given lattitude Europe climate much warmer than Midwest US due to the Gulf Stream.
That's my point. Norway is colder that most of Europe and almost as cold as Chicago. If heat pumps can work in Norway, then they can work anywhere that's warmer.

Latitude doesn't matter. Heat pumps don't depend on the angle of the sun at noon. The same heat pump will work in the same climate, regardless of the latitude of the location that has that climate.
LotsaGray wrote: Mon May 29, 2023 10:06 pm Heat pumps don’t run in reverse they expand the fluid at a different point in the circuit. The expansion occurs after the evaporator (which makes that name a misnomer). I fully agree that design changes can improve the heating performance of a HP but that isn’t what OP is likely to get.
Heat pumps run in reverse because the evaporator becomes the condenser, and the condenser becomes the evaporator. That's why the terminology is different for a heat pump. Instead of an evaporator and a condenser, you have an inside unit and an outside unit. Either one can be the evaporator, and the other one is the condenser.

It is the entire system that gets reversed. It's not the fan spinning backwards.
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