The heat pump I just had installed in SW Ontario hands over heating duty at -10C to the gas furnace
Comment on Heat pumps can't take the cold? Nordics debunk the myth
obinice@lemmy.world 8 months ago
How is this a myth? Nobody with more than two braincells thinks that heat pump heaters don’t work in the cold.
If we start comparing everything that idiots think to a mythological mystery worthy of note, we’ll be here for an eternity.
PizzasDontWearCapes@sh.itjust.works 8 months ago
whoisearth@lemmy.ca 8 months ago
How much did it cost and what rebates are available? I’d love to say fuck Enbridge.
MaxHardwood@lemmy.ca 8 months ago
It really depends on the type of heat pump. Air-sourced heat pumps generally don’t produce heat below -30C and below -10C they generally lose enough efficiency that you’re better off using electric baseboard heating.
Thorny_Insight@lemm.ee 8 months ago
My air sourced heat pump keeps my house warm just fine in the Finnish winter where temperatures of -30C aren’t unheard of. I’m not exactly sure how it works, but I assume there’s coils that’ll produce the the if nececcary, making it at worst as efficient as direct electric heating, which is what I’d use otherwise. Here like every other house has a heatpump like that and I don’t remember hearing anyone ever complaining that it’s not working.
Drewlb@lemmy.world 8 months ago
The argument is bullshit in totality. But… When the supplemental electric heating coils come on, it is less efficient ON THAT DAY, than the alternative electric options. But, like I said, in totality, it’s more effective over a month, and certainly better over the course of a year. It’s a matter of people with an agenda cherry picking the 9 days a year in which it is less efficient and pretending that the other 354 days don’t count.
Thorny_Insight@lemm.ee 8 months ago
When the supplemental electric heating coils come on, it is less efficient ON THAT DAY, than the alternative electric options.
It depends what you mean by the alternative electric options. Electric resistance heating is 100% efficient and that’s what my heatpump effectively is when it gets cold enough. It’s not less efficient than wall mounted electric radiators even when it drops to -30C. You just lose the efficiency of a heatpump for that time.
xthexder@l.sw0.com 8 months ago
Except that electric heating is always 100% efficient, and that’s what a heat pump falls back to. If anything it will still be more efficient than baseboard heating simply due to it having a fan to better distribute the heat (equivalent to an electric furnace with ducting). The only argument that makes sense is when comparing costs with other heat sources like natural gas, which is a whole other topic.
Kelsenellenelvial@lemmy.ca 8 months ago
I suppose if electric heat is the primary option then sure. Around here though natural gas is pretty much ubiquitous and the cost per joule is a heck of a lot lower than electricity. About $6/GJ for natural gas, compared to about $42/GJ for electricity. Would need a pretty efficient heat pump to see the cost savings in my area.
MaxHardwood@lemmy.ca 8 months ago
I think mine is undersized and close to 20 years old now. Reading your response is yet another reason I have to go through with upgrading everything.
Iamdanno@lemmynsfw.com 8 months ago
It’s not that people think they don’t work in the cold, it’s that they are less suited for the areas or days of extreme cold.
OminousOrange@lemmy.ca 8 months ago
Which is why you have a backup system. I have a net zero house in Saskatchewan, Canada. My Carrier heat pump will operate to -15C, and switches to electric heating coils in the air handler if it’s colder outside. It’s a rather extreme climate here, but in most other places, you’d be fine with some baseboard heaters as backup.
echodot@feddit.uk 8 months ago
It just comes from a fundamental misunderstanding of how the universe operates.
They say oh well it’s cold outside so how can it make it warm inside? They say this because they have absolutely no understanding of where the concept of a temperature comes from. They think that if it’s 10° outside then there is 10° of energy outside presumably out to some arbitrary distance, because some places are warmer, but they don’t really think that bit through. They don’t realise that’s not how it works.
pedalmore@lemmy.world 8 months ago
MFers need a refresher on the concept of absolute zero.
Buffalox@lemmy.world 8 months ago
This is not a myth but a fact, heat pumps don’t work at extreme cold temperatures.
What temperature exactly depends on the coolant used.
The efficiency also degrades as the temperature nears the minimum it works at.
This is a random example of first hit I got on a heat pump.
heatnow.dk/produkt/altech-sirius-9-varmepumpe/
Notice the effect drops dramatically below -20 C°.
But this is a pump sold for the Scandinavian market, therefore it is of course designed to work at low temperatures. It doesn’t state the minimum, but I’m guessing it would be around -40 C°. Which is very good compared top older models.
AA5B@lemmy.world 8 months ago
But that’s not sufficient. As the temperature gets colder, it’s not just less efficient but produces much less heat. At the lower temperatures, it may not be able to keep up. Since it would be wasteful most of the year, heat pumps aren’t sized for that
Buffalox@lemmy.world 8 months ago
IDK why you are downvoted, this is exactly true. The pump can only use it’s max power, at max efficiency it generates 4-5 times that power in heat. But at temperatures below what the coolant allow, it only produce heat equivalent to the power put in, or a 4th to a 5th it’s max output.
The Heat pump shown however, does go very low, and it would be exceptional if the limit was reached. But just a decade ago, most heat pumps couldn’t go nearly that low, and lost efficiency quickly already below zero Celsius.
AA5B@lemmy.world 8 months ago
Here in New England as far as I can tell, HVAC contractors tend to recommend hybrid systems, with a gas furnace as the secondary heat. However maybe that’s because gas is much cheaper than electricity.
Maybe there’s a contractor around who can give a better opinion on whether my experience is general