Let me say at the outset that I have one of the most efficient heating and cooling system one could possibly imagine. At my place in Michigan, I have an artesian deep well that will still move about 2 gpm at a head of 10 feet….. Suffice it to say that this makes for a really inexpensive heating and cooling system since this is flowing all the time and has been for about 15 years when a previous owner put it in the well. I won’t go into further detail with this because the heat pump system I’m using with it is not all operational yet with monitoring equipment and so it is not yet at the point where I have good data on it. However, the well water temperature is about 48 degrees and so this will be way better than any kind of ASHP (air source heat pump) and I’m not using any energy to move the water.
There is a bunch of information in these comments that could benefit from ‘actual technical information’… I’m not saying that what I’m going to suggest here is complete technical information since of course every situation is different but some of the links below may change some thinking on the issue of heat pumps for cold temperature. That of course assumes it is accurate but until proven otherwise, I’ll assume it is…much of this ultimately comes from ‘Energy Star’ and if you want to argue a point, may I suggest you take up that argument with the Department of Energy.
I too have always believed that for cold temperatures, heat pumps were useless because that was what I saw back in the 70s and 80s… after all, whatever thermal energy is left in the air gets to the point where it takes more energy to extract it than what is in the air. That sentiment is obviously also the case with many of the posters on this thread. My thinking on this changed some time ago…. I’m not sure what the heat pump manufacturers are all doing differently since obviously the laws of thermodynamics haven’t changed but here is one of the pieces that really got me thinking…..
https://www.youtube.com/watch?v=wCZrBI3PFag This is a video taken in 2019 by a guy in Minnesota who was monitoring his heat pump system when the temperature was in the -25 degree range. He was still able to get sufficient heat that his supplemental heat sources (resistance heaters) were not clicking in. It’s a really interesting video as he has a thermal cam so you can see that the temperature gradient looks like.
The Department of Energy has put out tons of funding to develop heat pumps for cold temperatures…. Carrier, Trane and Lennox all have availed themselves of the corporate welfare and as good as COP was already for some of their low temperature units, it sounds like in this piece that there will be some new products on the market in 2024 that takes things to yet another level…. https://www.pv-magazine.com/2022/11/03/air-source-heat-pump-for-harsh-cold-climates/
To be clear, the technology of heat pumps is not what I consider to be ‘my area of expertise’ but it is in a closely related field (my company solves aerodynamic and air movement problems and engineers solutions for large industrial fans). Since it is closely related, I keep my eye on ‘HVAC issues’ and recently got interested enough to take in several webinars. What I was looking for was good information on the COP for commercially available heat pumps… this for another property I own that is also in a cold climate. ‘Energy Star’ is the rating arm that the Department of Energy use for all kinds of equipment that we regularly see stickers on and I wanted to see a good simplified summary of what they said on heat pump COP. That opportunity came on March 7 when I ended up taking in a webinar put on by a group called SaveOnEnergy….this is a group in Ontario that administers the Province’s energy efficiency programs. Anyway, the webinar was called “Introduction to Air Source Heat Pumps: Installation Best Practices Series for Homes” and in that webinar, slides were shown for the COP. When you click on the next link, it opens up a pdf of the presentation…. go to slides 14 and 15 to see the COP data and for the record, they use the Energy Star data for what was put together. On slide 15, they show the COP for what they refer to as three models of heat pumps and there is a note on the side of the slide that says this…. “ENERGY STAR classifies a Cold Climate Heat Pump as one that can maintain a coefficient of performance (COP) of at least 1.75 at -15C (5F)”. Regardless, take a look at what the COP is for the one called Model 1…. It has a COP of 3 at -25 degrees C (which I calculate to be -13 degrees F)!
https://www.saveonenergy.ca/SearchResults?q=heat+pumps If interested, this is a link that takes you to a bunch of the webinars that SaveOnEnergy has put on with heat pumps….
https://natural-resources.canada.ca/sites/nrcan/files/canmetenergy/pdf/ASHP%20Sizing%20and%20Selection%20Guide%20(EN).pdf For those interested, this is a fairly comprehensive guide on heat pumps…. guide was put together in Canada where they at least have some idea of what ‘cold’ is…..
Another reference….. https://www.consumerreports.org/heat-pumps/can-heat-pumps-actually-work-in-cold-climates-a4929629430/ Here’s a fairly recent Consumer Reports article with the title “Can Heat Pumps Actually Work in Cold Climates?..... Yes, they can—if carefully chosen and properly installed. Here’s what you need to know.”
https://www.nrel.gov/docs/fy11osti/52175.pdf This link takes you to a Department of Energy study that is a follow up to the excellent link that Lockbox posted in Post 27…
https://www.youtube.com/watch?v=H3jIRRzF6d0 Video on ‘Major Advances with Heat Pumps in the Extreme Cold’ (2023). Just more information on low temperature heat pumps… not as interesting as the Minnesota video but decent info.
Thanks for this informative post!
[Let me say at the outset that I have one of the most efficient heating and cooling system one could possibly imagine. At my place in Michigan, I have an artesian deep well that will still move about 2 gpm at a head of 10 feet….. Suffice it to say that this makes for a really inexpensive heating and cooling system since this is flowing all the time and has been for about 15 years when a previous owner put it in the well. ]
yes,
would even argue that heat pumps and even electric cars are appropriate for some people and situations.
We used to have something called appropriate technology.
even the geo thermal heat transfer may work if appropriated designed and managed. big if , let me repeat that big if. I have heard of lots of problems. My observations is they still install a back up system whether electric heat or a gas furnace backup.
the more technology the more to go wrong and you are waiting for parts and repairs.
THE WHOLE SYSTEM NEEDS TO BE LOOKED AT. systems are complicated and I don’t have time for another hobby nor want to spend money on service which also reduces the NET savings.
Again, consider the heat pump electric htrs in the basement during the winter. Where is the heat coming for several months? The furnace in your basement. The summer months it cools the basement which is good. But the govt kids just look at the summer months and think the savings is for 12 months. I would install one in the south if i lived there.
Appropriate technology, not one size fits all.
All great in your situation or where someone has unlimited running water. But these idiot climate hoaxers are demanding Therese for the entire state (nation soon to follow). What will a 50 unit apartment in Yonkers use for the heat sink? Where will the electricity come from. Where will the plumbing occurs? AND, how soon after they are mandated and somehow installed until the same clowns ban the chemicals and refrigerants, in the combo units?
But of course we are talking about saving the entire planet so nothing is too extreme...or stupid... for a politician.
Disclosure. I did work for a company that design seawater heat pumps for tropical applications. I didn’t do work on the heat tranfer side. Not smart enough for that. I did the mechanical designs and CFD analysis. I never saw a project to completion but it looked great on paper.
Wow! You have an excellent ground source with that well!
Wow!
Thanks for all the interesting info...
I just remember visiting family in northern MN in the 1960s and re-learning what “cold” weather was...
I say “re-learning” because of my time in Korea in 1951-1952...
Thank you for that.
Your method of using an underground water source is great. I had the same thought on a lake house I looked at. The water temperature was about 55 to 65 degrees year round since the water came off the bottom of a damn. Just using that water to keep the house air in that temperature range to start before additional heating or cooling is a major energy saving.
Speaking of aerodynamics, maybe you can weigh in on this.
I ride a motorcycle. Hot & cold weather. Usually I like to stay at 45 or above in the cooler months.
No one in any of my riding groups agrees with me, but I think riding at 45 feels like the aerodynamics are minutely different than at 80. Everyone else says it’s my imagination.
Thanks, hectic skeptic.
I read the Rah-Rah heat pump site from an earlier poster (Brian Griffin), and it had both useful information, and some caveats.
The useful information is that compared to earlier-generation heat pumps, a log of modifications have been performed to the tubing which performs the heat exchange; IIRC (I was up too late last night) these involved scoring and/or changes to surface area;; and improvements to the fans and motors.
The compressors have been changed to be variable speed (this follows similar innovations in furnaces and air condtioners, the latter of which are also heat pumps).
Thd caveats were that they recommended you both seal and insulate your home...which sounds suspiciously like the heat-pump company writing themselves a large check while allowing themselves plausibile deniabililty.
I’ll tty to get time to read through your sources (maybe next three weeks) but for the moment I remain skeptical.
I have had experience with “older” heat pumps maybe 30 years ago, where during single-digit weather, maybe up to the mid-teens, the heat pump pushed out “luke-cool” air...
The issue I have with heat pumps is it always feels like your AC is on because its never blowing hot air like a gas furnace.