realistically considering equipment available today most people thinking about heat pumps in cold climates would be better served by geothermal systems than air source
Most places with boilers are too cold for air to air heat pumps to be viable during heating season. Geo-thermal heat pumps have a wider range but they involve significant site work and require a non-trivial lot size. In terms of expense a typical geothermal heat pump will have a very long payback period. An open loop geothermal heat pump might be practical if there’s a source and sink for the water running through it. Most people don’t have those. But it’s a simple system with a water pump and fan as the only moving parts.
But geothermal heat pumps are interesting in cold climates because air-air and air-water heat pumps (the most common and affordable types) are less efficient below freezing, so I feel like that confirms rather than dispels the myth!
Open air heat pumps have a lower limit for their operating temperature, so can't be used efficiently in cold climates (around < 25F), since they start to use more energy than they provide as heat. Geothermal heat pumps solve this, but cost more.
Gas is somewhere around half the cost of electricity. Back in the day, you would still profit with a GPU.
I'm not used to think of ground source systems as simply heat pumps... I think of them as geothermal systems. Maybe because the installation is lot more involved.
But in places like Florida, if you have a 15+ year old A/C, replacing it with a conventional modern heat pump, it would probably pay for itself in a few years.
For nordic climates: After running the numbers I was surprised by how little benefit I'd get from geothermal drilling + heat pump for a much larger investment (like $30k including internal fitting of water-based radiators) compared to a regular outdoor air/air heat pump for $2k. Ongoing costs would be like 5-8% lower.
True. Geothermal heat pumps will always be better but given that you can get an air source heat pump for 10^3 to 10^4 dollars while a geothermal setup will cost you 10^4 to 10^5, geothermal becomes prohibitive for most residential setups.
The capital costs of retrofitting a ground source are prohibitive though, so 'just use a heat pump' isn't useful advice for millions of people that live in regions where the air gets cold enough to limit the effectiveness of a heat pump.
Yep. The real selling points of heat pumps is comfort, since they can go from aircon to heat and back seamlessly. Where I live geothermal heat pumps are the practical option, but south of Pennsylvania the air source heat pumps are a great option.
The geothermal heat pump is different from what they’re talking about but it is for real.
About 10 years ago the word was that the climate in Upstate NY was too cold for an air source heat pump but the air source heat pump was a great choice a little bit south. Recently air source heat pumps have improved and are recommended for New York and even Alaska.
Modern air source heat pumps are fine. Where I live it's hard to even find someone who services ground source heat pumps. Ground source works slightly better but the install cost is so much higher that it's rarely worth it.
> Practically nobody does geothermal heat pumps here. The up-front cost is waaaaaay higher than any kind of normal (for us) set-up, not many people do it so that makes the cost even higher because the installation market is tiny, and energy costs aren't high enough to make the extra tens of thousands of dollars a good investment.
This isn't true in all parts of the US. A family member of mine has had an open loop geo-thermal system for almost a decade now, and they're definitely not the only one in the area.
I'd say about half of my neighborhood has air source heat pumps and about a quarter of the remaining have geo-thermal (vertical loops).
There are two HVAC businesses in my area that specialize in nothing but ground source heat pumps. If there was no market, they'd be out of business.
I think, where I am, it's harder to find a cognizant air source installer. Most of the HVAC businesses here are still under the misconception that air source isn't viable in our northern locale and often don't try to sell, or try to talk people out of them. But my air source is able to heat our house easily at 0F and is rated to run below -10F. It's currently my main heat source. Over the course of winter I'd guesstimate 60-70% heat pump heating overall.
When I read the title, I wonder why air to water and air to ground heat pumps aren't more common in cold climates. Where it is 0°f on the surface, a few feet deep and you're back to 46°f.
So we could have had efficiency 10 years ago instead of today?
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