4 ms·

They are used a lot in hot climates but from what I heard, they aren't very efficient in cold climates.

by Pakdef 4y ago

MBCook 4y ago
My understanding is newer models are much better.
PaulHoule 4y ago
In upstate NY an air source heat pump is not viable but ground source heat pumps are fine. If you go south a bit, say to North Carolina, the air source heat pump looks like a good idea. Either way the capital cost of a heat pump is high and people seem to have a psychological aversion to spending money on capital costs. One of the best selling points of a heat pump is comfort: it switches continuously from heating to air conditioning. An eco-sensitive person in Upstate NY might not really think they need air conditioning. It's not like buying a Toyota Corolla to save the planet, it's more like buying a Cadillac Escalade to save the planet and the psychology doesn't really work for that. See https://energysavingtrust.org.uk/air-source-heat-pumps-vs-ground-source-heat-pumps/ https://energysavingtrust.org.uk/air-source-heat-pumps-vs-gr...
- Pakdef 4y ago
  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.
- theluketaylor 4y ago
  Newer refrigerant and designs for air source heat pumps are a lot more cold weather capable than many people think. Quite a few installations are more efficient than resistive heating down to around -13 F / -25 C and don't need a defrost cycle. Plenty of places get or stay colder than -25C, but that is often short stretches or overnight. There are a lot of places that would do better with a little resistive heat backup compared to the huge installation costs for ground source. New neighbourhoods in cold climates should be required to install community ground source heat pumps. Since all that dirt is moving anyway the cost of trenching is negligible and any drilling is amortized over many properties.
  - hasmanean 4y ago
    All utilities will be much cheaper if they are amortized over many properties. Heat pump capital costs are too high. They should be standardized or designed to be cheap and used everywhere…to recover waste heat from everywhere in the home.
    - theluketaylor 4y ago
      Air source heat pumps don't cost significantly differently from gas furnaces or boilers, especially once you account for running costs. Anyone with A/C already has an air source heat pump, just one that only moves heat from inside the house to outside. Moving heat in both directions take some extra valves and an extra heat exchanger, but this doesn't dramatically increase costs. The basic principal and components are exactly the same. Ground source is expensive, but that's due to drilling and/or trenching. The actual heat pump is a tiny fraction of the bill to install ground source heating.
- wrycoder 4y ago
  I'm interested in air/water heat pumps for slab heating[0]. In the summer they can be reversed to provide cooling, so long as you keep the slab zone above the dewpoint and provide additional wall-mounted exchangers in other zones as needed. [0] https://www.chiltrix.com/chiller-technology.html https://www.chiltrix.com/chiller-technology.html
- ashayh 4y ago
  Not true https://www.nrel.gov/news/features/2021/even-in-frigid-temperatures-air-source-heat-pumps-keep-homes-warm-from-alaska-coast-to-us-mass-market.html https://www.nrel.gov/news/features/2021/even-in-frigid-tempe...
Lindby 4y ago
in Sweden we use them a lot. Most of the time they work really well and it's not like they are useless just because it gets really cold. They still help a lot even if the traditional heater element might need to kick in for short periods. It's usually not until 20 below freezing that they don't add much, but those temperatures are not a daily occurrence for most of us.
ashayh 4y ago
Myth: https://www.nrel.gov/news/features/2021/even-in-frigid-temperatures-air-source-heat-pumps-keep-homes-warm-from-alaska-coast-to-us-mass-market.html https://www.nrel.gov/news/features/2021/even-in-frigid-tempe...

They are used a lot in hot climates but from what I heard, they aren't very efficient in cold climates.

by Pakdef 4y ago

They are used a lot in hot climates but from what I heard, they aren't very efficient in cold climates.

MBCook 4y ago

My understanding is newer models are much better.

PaulHoule 4y ago

In upstate NY an air source heat pump is not viable but ground source heat pumps are fine. If you go south a bit, say to North Carolina, the air source heat pump looks like a good idea. Either way the capital cost of a heat pump is high and people seem to have a psychological aversion to spending money on capital costs. One of the best selling points of a heat pump is comfort: it switches continuously from heating to air conditioning. An eco-sensitive person in Upstate NY might not really think they need air conditioning. It's not like buying a Toyota Corolla to save the planet, it's more like buying a Cadillac Escalade to save the planet and the psychology doesn't really work for that. See https://energysavingtrust.org.uk/air-source-heat-pumps-vs-ground-source-heat-pumps/ https://energysavingtrust.org.uk/air-source-heat-pumps-vs-gr...

Pakdef 4y ago
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.
theluketaylor 4y ago
Newer refrigerant and designs for air source heat pumps are a lot more cold weather capable than many people think. Quite a few installations are more efficient than resistive heating down to around -13 F / -25 C and don't need a defrost cycle. Plenty of places get or stay colder than -25C, but that is often short stretches or overnight. There are a lot of places that would do better with a little resistive heat backup compared to the huge installation costs for ground source. New neighbourhoods in cold climates should be required to install community ground source heat pumps. Since all that dirt is moving anyway the cost of trenching is negligible and any drilling is amortized over many properties.
- hasmanean 4y ago
  All utilities will be much cheaper if they are amortized over many properties. Heat pump capital costs are too high. They should be standardized or designed to be cheap and used everywhere…to recover waste heat from everywhere in the home.
  - theluketaylor 4y ago
    Air source heat pumps don't cost significantly differently from gas furnaces or boilers, especially once you account for running costs. Anyone with A/C already has an air source heat pump, just one that only moves heat from inside the house to outside. Moving heat in both directions take some extra valves and an extra heat exchanger, but this doesn't dramatically increase costs. The basic principal and components are exactly the same. Ground source is expensive, but that's due to drilling and/or trenching. The actual heat pump is a tiny fraction of the bill to install ground source heating.
wrycoder 4y ago
I'm interested in air/water heat pumps for slab heating[0]. In the summer they can be reversed to provide cooling, so long as you keep the slab zone above the dewpoint and provide additional wall-mounted exchangers in other zones as needed. [0] https://www.chiltrix.com/chiller-technology.html https://www.chiltrix.com/chiller-technology.html
ashayh 4y ago
Not true https://www.nrel.gov/news/features/2021/even-in-frigid-temperatures-air-source-heat-pumps-keep-homes-warm-from-alaska-coast-to-us-mass-market.html https://www.nrel.gov/news/features/2021/even-in-frigid-tempe...

Lindby 4y ago

in Sweden we use them a lot. Most of the time they work really well and it's not like they are useless just because it gets really cold. They still help a lot even if the traditional heater element might need to kick in for short periods. It's usually not until 20 below freezing that they don't add much, but those temperatures are not a daily occurrence for most of us.

ashayh 4y ago

Myth: https://www.nrel.gov/news/features/2021/even-in-frigid-temperatures-air-source-heat-pumps-keep-homes-warm-from-alaska-coast-to-us-mass-market.html https://www.nrel.gov/news/features/2021/even-in-frigid-tempe...