The coldest temperature ever recorded in the UK is -27. That’s right around the inflection point for where heat pumps become less efficient than electric heaters. Until the gulf stream fails, the UK is pretty safe to use heat pumps everywhere.
The heat pump was the only source of heat in this Vermont home, and it was seen to deliver 15,000 Btu/h at –15°F, very similar to the capacity provided by the manufacturer. At most other sites, heat pumps were operated as supplemental heat sources. In very cold conditions, auxiliary systems provided most (or in some cases all) of the heating.
At Site 4, for instance, a Mitsubishi FE18 operated at COPs of 1.5–2.0 at outdoor temperatures of –10°F. The FE18 at Site 1, by contrast, operated at COPs of 1.0–1.2 at outdoor temperatures between 0°F and 5°F.
So yeah, going 100% air-source heat pump if you’re area regularly spends time around -30°C (-22F) might not be the best idea. Though even the last report you cited said it might be 1.5-2x as efficient as resistive heating. And that Site 1 with bad COPs was because they manually lowered the fan speed…
There are vanishingly few people who live in areas with weather consistently below -30C. I’ve been seeing that kind of concern trolling all over the place in the past year or so, and they always have the same song and dance about low efficiency in extreme cold - technically correct, but taken as part of the bigger context, so niche as to be practically irrelevant. Yeah, if you live in Yakutsk you won’t want to rely only on a heat pump. Big fuckin’ deal - the other 99.5% of people on earth can benefit greatly.
Edit: I wouldn’t be susprised if this is the exact same guy I once argued with on Mastodon, actually. He was German too.
The efficiency isn’t the only problem limiting colder climates, it’s the need to periodically defrost the outdoor coils. This process generally occurs by running the normal air conditioning (cooling) mode, which can increase occupant discomfort. There is a point where this breaks down before the COP decreases.
But only for the 4 weeks a year you spend in unusually cold weather, the other 48 it’s more efficient.
It’s not like truly arctic places are a reasonable application but the overwhelming majority of our population lives south of Quebec and north of Wellington. So it’s not a relevant point, everyone in the Arctic can just use resistive heating or burn fuel, and if we get everything else on heat pumps we reduce our enegy use by a factor of 2-3 regardles.
I’ll chime in here since I own 2 heat pumps and live in a cold climate (often below 20C). Our house is heated with 100% electricity and after installing heat pumps our power bill dropped by about 18%. That includes all electricity, not just heating, so the gain in heating efficiency was very considerable.
I’m a very big proponent of heat pumps. The original post I responded to simply said all you need to do is bury the lines, which I wanted to clarify was not the only factor to consider.
The coldest temperature ever recorded in the UK is -27. That’s right around the inflection point for where heat pumps become less efficient than electric heaters. Until the gulf stream fails, the UK is pretty safe to use heat pumps everywhere.
The UK is not what would be considered a cold climate. Also:
https://www.consumerreports.org/heat-pumps/can-heat-pumps-actually-work-in-cold-climates-a4929629430/
https://news.energysage.com/heat-pumps-cold-climates/
https://www1.eere.energy.gov/buildings/publications/pdfs/building_america/inverter-driven-heat-pumps-cold.pdf
So yeah, going 100% air-source heat pump if you’re area regularly spends time around -30°C (-22F) might not be the best idea. Though even the last report you cited said it might be 1.5-2x as efficient as resistive heating. And that Site 1 with bad COPs was because they manually lowered the fan speed…
There are vanishingly few people who live in areas with weather consistently below -30C. I’ve been seeing that kind of concern trolling all over the place in the past year or so, and they always have the same song and dance about low efficiency in extreme cold - technically correct, but taken as part of the bigger context, so niche as to be practically irrelevant. Yeah, if you live in Yakutsk you won’t want to rely only on a heat pump. Big fuckin’ deal - the other 99.5% of people on earth can benefit greatly.
Edit: I wouldn’t be susprised if this is the exact same guy I once argued with on Mastodon, actually. He was German too.
The efficiency isn’t the only problem limiting colder climates, it’s the need to periodically defrost the outdoor coils. This process generally occurs by running the normal air conditioning (cooling) mode, which can increase occupant discomfort. There is a point where this breaks down before the COP decreases.
Get a heat pump with resistive (electric) defrosting, not one that defrosts by running like an AC.
This kills your COP, making it inefficient.
But only for the 4 weeks a year you spend in unusually cold weather, the other 48 it’s more efficient.
It’s not like truly arctic places are a reasonable application but the overwhelming majority of our population lives south of Quebec and north of Wellington. So it’s not a relevant point, everyone in the Arctic can just use resistive heating or burn fuel, and if we get everything else on heat pumps we reduce our enegy use by a factor of 2-3 regardles.
Right. It depends on your climate.
The Guardian is a UK publication.
Ok? The article talks about the rest of Europe, of which their are numerous countries that are actually in colder climates.
I’ll chime in here since I own 2 heat pumps and live in a cold climate (often below 20C). Our house is heated with 100% electricity and after installing heat pumps our power bill dropped by about 18%. That includes all electricity, not just heating, so the gain in heating efficiency was very considerable.
20C is not a cold climate. If you mean -20, that’s not a cold climate either…
That’s literally the point where they start having problems, if you bothered reading my other post.
Removed by mod
Your behavior is completely out of line.
I’m a very big proponent of heat pumps. The original post I responded to simply said all you need to do is bury the lines, which I wanted to clarify was not the only factor to consider.