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Comment by Bhilai | Hacker News Reader

Definitely a lot of posts about heat pumps on HN recently that this topic has piqued my interest but only to the point that I want to know if I can install one in my home. Are there any legit resources out there that can help me understand if heat pump is a right choice for my home based on Geo, type of home, sqft and other factors to consider before replacing current systems (two ACs and two furnaces?)

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Generally, they can work anywhere in the continental US. (Assuming you live in the US.) If you're in northern NH, NY, VT, or Maine, you might want to keep your gas system as a backup. (New homes tend to have electric backup, but if you have an older home they just keep your furnace as backup.)

I have a 3000 sqft house in MA with a heat pump as my primary heat, and an electric strip as backup. The heat pump goes into the ductwork for most of the house. I generally haven't had problems. (It did have to be adjusted because it was the first time the installer put one in.) I have solar and usually get 1-2 large bills in January and February, and then March and April are very cheap, if I get a bill at all. My "large" January and February are comparable to what I'd spend on conventional heat.

Last weekend we had a "once in a century" cold snap down to -4. Most of the house was at temp, but one room fell to the high 50s. From what I've heard, plenty of people with conventional heat had far worse issues than a chilly room.

North Dakota and Minnesota are on average colder than the states you listed. I would also include Montana, Wisconsin, Wyoming, and Idaho as states where you should be concerned about performance in sub zero temperatures and have a backup heat source.

Around Vancouver our heat pump has performed adequately even down to -15C/5F. This may be related to it being a deep ground loop geothermal setup (vertical instead of horizontal), and the type of building (concrete). We do have a gas fireplace as backup, but have not needed it at the temperatures we see in this corner of the world.

I'm air based.

When I built my house, I called around and it didn't sound like geothermal works very well where I live. I suspect the reason why I was talked out of it is because my yard is very rocky.

It is definitely related to it being a deep ground loop geothermal setup. An air-to-air heat pump is trying to get heat out of air that has less heat as it gets colder. A ground loop heat pump is trying to get heat out of water that is not affected by the temperature of the outside air.

With an air-to-air heat pump, you need a backup system for when it gets too cold out for the heat pump to pull enough heat out of the air, and for power outages. With a ground loop heat pump, you only need a backup system for when the power goes out because the ground water will never be too cold for the heat pump to pull heat out of.

If you already have a central AC system, a heat pump is more or less a drop in replacement. The heat pump becomes both your heat and AC unit.

Heat pumps are now the most premium option on units offered by the well known names in HVAC- Trane, Carrier, etc.

In terms of suitability for your climate, they should work just fine for most people- they start to struggle if you are in an area when temps get down to about 10 degrees Farenheit, though they improve in this area each year. Even if you live in an area that cold, there are options to mitigate this- leaving your current furnace hooked up to be turned on during those cold periods, etc. What it comes down to is it just gets more expensive if you live in these colder areas, but over time the energy savings should give you a return on your investment in less than ten years.

My Air conditioner blew this fall, so I am actively in the process of getting bids for heat pumps.

My $0.02 are that any competent and honest HVAC company will be able to walk you through the concepts of your home's heating/cooling load etc. and what size heat pump can meet that need, what it costs to run annually, and what incentives there are. It's not that hard. I would reach out to three highly ranked (or word of mouth suggested) HVAC co's and start the conversation.

I guess they are a new thing in the US. In Europe installing a heat pump with floor heating is done for practically every new family house. It is the cheapest (for us) and nicest way to heat up your home. Though very few people build houses out of wood, unlike the US.

What are the houses usually made of? Stone?

Engineering/perforated bricks mostly. North Germany/UK is a lot of solid red/gray bricks, not sure if new homes still use that style, since it has terrible insulation. If built with perforated bricks a home will also put a thick layer of styrofoam for insulation on the outside.

What climate zone are you in? (assuming US) https://learnmetrics.com/wp-content/uploads/hspf4-and-hspf5-...

If you're in 1, 2, or 3, heat pumps are definitely the right option. In zone 4 or 5, newer cold temperature heat pumps are a good idea. In 6, 7, or 8 it's less of a sure thing, and you will likely want a backup source for the colder days.

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