this post was submitted on 12 Sep 2023
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Oxford study proves heat pumps triumph over fossil fuels in the cold::Published Monday in the scientific journal Joule, the research found that heat pumps are two to three times more efficient than their oil and gas counterparts, specifically in temperatures ranging from 10 C to -20 C.

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[–] DarthBueller@lemmy.world 14 points 1 year ago* (last edited 1 year ago) (71 children)

They're only two to three times more efficient if they aren't frozen solid. Don't know how it works in Canada, but my mini-split heat pump can't handle a week of 10F let alone -20 C - sure it will put out some heat, but it absolutely needs to be supplemented with my wood stove. And I live in the South. Maybe there's some new high tech heat pumps that cost a fortune and don't freeze over in the insane temps of the great white north? EDIT: hey, folks, how about actually responding instead of downvoting me? If I don't have a clue, please enlighten me. Fuckers.

[–] TooManyGames@sopuli.xyz 15 points 1 year ago (1 children)

My air heat pump has been ticking away happy for 15 years with no issues. It's worked fine warming up the house when it's -20°C in the winter and cooled nicely in the up to +30°C in the summer.

I do supplement it using electric heating and a fireplace though.

[–] DarthBueller@lemmy.world 5 points 1 year ago (2 children)

Thank you for responding and sharing your counter-experience. Greatly appreciated. What keeps your unit from icing over? Are they designed differently in northern climates?

[–] bamboo@lemmy.blahaj.zone 11 points 1 year ago

Here's a good video showing how the heat pump will reverse and basically dethaw the coils when it freezes over: https://youtu.be/7J52mDjZzto?t=1317

[–] Mr_Blott@feddit.uk 2 points 1 year ago (1 children)

They're spreading all over the Alps too. Easily a 50° temperature difference between summer and winter, and they tick over nicely for years with no problems

I think in Europe it's a fairly common method now so reliability has been sorted out.

Generally the US is a decade or so behind everyone else though so it might take a while

[–] MigratingApe@lemmy.dbzer0.com -4 points 1 year ago (2 children)

The COP coefficient falls down drastically to 1 as soon as temperature drops below -5C and they basically start working as an electric heater. It wouldn’t be a problem if I wasn’t living in a country with the most expensive electricity in Europe which is produced mainly from coal…

[–] alvvayson@lemmy.world 6 points 1 year ago (1 children)

Then you're looking at the wrong models.

The Mitsubishi H2i has a COP of 2.88 at -15 C (5 F).

There are also models with COP above 2 at -30 C.

Yes, a typical A/C isn't designed for subzero temperatures. But you gotta get the right heat pump for the right climate.

For cold climates, it does get more expensive and less efficient and at some point it will always be cheaper to just burn wood or fossil fuels. But with the right heat pump, even very cold climates can get most or all of their heating cheaply with a heat pump.

[–] MigratingApe@lemmy.dbzer0.com 1 points 1 year ago (1 children)

Hah look at the downvotes, you can’t have civilized discussion these days.

Your last paragraph and my last sentence is the whole culprit for me. The money I have to pay here for good heat pump with COP 2 at -30 and the associated electric bills have currently no chance here to ever be cheaper than burning gas either nor more friendly for the climate where my government burns coal to produce electricity.

And no, I cannot install enough solar to power this heat pump in the winter or offset the cost of electricity during summer (inverters already turn off in the summer, no electricity is produced as too many neighbors have solar and voltage rises above shutdown threshold in the grid)

[–] alvvayson@lemmy.world 1 points 1 year ago

Solar in winter for high latitudes is never gonna work, fully agree on that.

But at some point a hybrid system will be cheaper for part of the year than a pure gas system, at any latitude.

Whether it justifies the investment is indeed a cost/benefit analysis.

Downvoting on Lemmy is toxic, fully agree on you there. It really stifles healthy discussion. It seems Lemmy is engineered by communists who only want agreement lol. 😂

[–] Mr_Blott@feddit.uk 4 points 1 year ago

Yeah that's just incorrect. People wouldn't use them then. All new build chalets have them

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