Comment by wood_spirit
19 hours ago
In the nordics it is common to have ground source heat pumps (brine in closed circuit pipe or bore hole) that are run backwards in summer to cool the house while actually assisting in storing heat back in the ground to extract in the winter. It’s a bit like regenerative breaking on electric cars.
No it's not. It exists but it's certainly not common for individual dwelling to use ground source heat pumps, at least in Norway. It is more common in Sweden[1] but still far less common than air source and over 90% of heat pump installations in Norway are air source[2].
The only ground source installations I can think of in Norway serve large office buildings and similar. The largest heat pump installation I know of in Norway is actually a third kind: water source[3]. It takes heat from the Drammen river to provide heat for a district heating system and for keeping the town centre clear of ice in the winter as well as supplying the new hospital with heat.
I imagine that the rest of the Nordic region is similar.
See:
[1] http://publications.jrc.ec.europa.eu/repository/bitstream/JR...
[2] https://www.sciencedirect.com/science/article/pii/S221313882...
[3] https://energiteknikk.net/2023/11/drammen-fjernvarme-storst-...
If by Nordics you mean Norway, Sweden and Finland, then the most correct way to say would be that ground source heat pumps for redidential heating are (very) common in Sweden and Finland, especially in newer and larger buildings. Norway is somewhat different in energy and climate perspective than its eastern neighbours.
The biggest reason to not install ground source heat pump is high installation cost. This means that it makes more sense for larger residential buildings. Also If you have district heating available then this might be more economical in the long run.
In Finland around 50% of new single-family homes use ground source heat pumps. So it's definitely popular here.
3 schools in my neighborhood (barneskole, ungdomsskole & videregående) all use ground source heat pumps.
There was a new in 1988 house in Champaign, Illinois, USA that used the same system, and i mention that because it was a normal modern house, and it's the only one i've heard of with that system.
It seems so smart.
There's a pretty significant upfront cost in getting them drilled, and many homes need the vertical drilling if they don't have sufficient yard space for a horizontal system. It gets harder if you have your own septic drain field too, as that will complete for yard space.
The cost difference is pretty massive- 3-10x for a vertical system. If you live in a city or a suburb with tiny lots, that's your only option though.
Nat gas and central AC are way cheaper.
I paid about EUR 4500 for a 114 meter drill hole including installation of brine (ethanol in my case actually) and removal of spoils. My 8kW heat+water pump was about EUR 7000.
I can spec out a gas burner for about EUR 4000 and a central AC for EUR 5000, but I bet the efficiency of the ground source heater would quickly trump the cost of buying gas regularly.
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Although if you needed a new septic field, I would think ground source thermal would be significantly deeper than a drain field which is only like a foot or so down so you could stack them.
Air source heat pumps are insanely more efficient and just plain better these days too. It used to be that if the air was below 40F you couldn't heat your house with a heat pump. Now, you can heat your house even when it's -10F
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It's expensive. A relative has one in the northern Great Lakes, they wouldn't have installed it if their house had access to natural gas.
Our house came with one and we upgraded the unit a few years ago. It's very efficient in terms of units of energy consumed, but in my area of the world gas is significantly cheaper than electricity so it ends up being expensive to run.
That said, we will install solar at some point and then it'll be "free" HVAC.