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Heat Pumps – The Well-Tempered Future of A/Cs

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151–160 of 406 posts

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#151

My 20 year old air conditioner recently died and I was looking into replacements. In my climate the temperature ranges from 40C in the summer, and -40C in the winter. After doing some research, it seemed pretty clear that having a furnace+AC was the way to go for my climate. Hardly a magic bullet technology.

Where do you live (general area) that you get -40 C often enough for it to matter?

Do you mean real -40? Or wind chill "-40" which doesnt affect HP?

Edit: Edmonton?

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#153
post #137

Earlier quoted context omitted.

-40C? That's an extreme situation. Heat pumps can be installed with backup heating as I understand it.

> Heat pumps can be installed with backup heating as I understand it. Then, what's the point? If you still have to have gas lines and infra, just use the gas. It's vastly cheaper.

That depends on the temperature difference. For smaller differences, heat pumps are much more efficient, but at some level they lose efficiency and gas is cheaper.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#154

My 20 year old air conditioner recently died and I was looking into replacements. In my climate the temperature ranges from 40C in the summer, and -40C in the winter. After doing some research, it seemed pretty clear that having a furnace+AC was the way to go for my climate. Hardly a magic bullet technology.

-40C? That's an extreme situation. Heat pumps can be installed with backup heating as I understand it.

Fahrenheit or Celsius?

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#155

I was looking for a whole home heat pump and got some quotes that started at $27,000 for a home that is 1800 square feet. That price is a bit hard to swallow. I really don't want to just cool one or two rooms in the house.

Are you sure you aren't getting quotes for a ground-sourced (AKA geo) heat pump? We just installed a 4.5 ton (overkill for your sqft) 20 seer unit for $18000.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#156

Earlier quoted context omitted.

This persistent myth just needs to go away. People use heat pumps all over Scandinavia, including in the arctic circle. They are extremely popular there. They were early adopters of this technology there decades ago. There are two popular varieties: - Ground source heat pumps. Those work pretty much anywhere; just dig below the perma frost and you are good to go on the northern tip of Canada, Alaska, Norway, or where…

The myth exists because the US is probably 10-20 years behind Europe and China in terms of HVAC and insulation technology. I recently had some reasonably high efficiency heat pumps installed at my house, and I’ve been very unhappy with the low temperature performance. It doesn’t even get very cold here—rarely below 5F (-15C) and a record low of -8F (-22C). The heat pumps I got (recommended by the well-regarded local…

Sounds like the units you are describing don't have an efficient (read 'big enough') heat-exchanger which is why they aren't being effective in not-so-low temperatures. The temperature of the cold-side should not be below outside ambient temperatures if the heat exchanger coils are sufficient.

In other words heat-energy should be going into cold side of the heat-pump (even at a low temperatures) at the same rate as it is coming out the hot-side at high temperatures. Reduce the heat in, and you will reduce the heat out.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#158
post #137

Earlier quoted context omitted.

> Heat pumps can be installed with backup heating as I understand it. Then, what's the point? If you still have to have gas lines and infra, just use the gas. It's vastly cheaper.

> Then, what's the point? If you still have to have gas lines and infra, just use the gas. It's vastly cheaper. A) Not everywhere B) Heat pumps can be powered with solar, reducing costs even if your gas would normally be cheaper C) Some people are willing to spend a little more if it helps push electrification forward, for environmental reasons

D) Carries the risk of killing you with CO.
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