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To heat a home with geothermal, you use a heat pump. It works better than an air source heat pump most places because the ground doesn't get as cold as the air

by wffurr 5y ago

To heat a home with geothermal, you use a heat pump. It works better than an air source heat pump most places because the ground doesn't get as cold as the air does. More widely deploying ground source heat pumps for home heating seems more promising than pursuing geothermal electricity generation. The problem with ground source heat pumps is that the lifecycle of the equivalent if 30-50 years, well outside the typical homeowner's planning or payback horizon.

coryrc 5y ago
For the same cost we could install multiple air-source heat pumps at nearly the same efficiency. That's a way better tradeoff.
Johnny555 5y ago
I wish ground source heat pumps were more affordable, I asked my HVAC installer, he said I was looking at $30K+ including returning the yard to the state it was in before they trenched in the pipes. That's 3X the cost of the air source heat pump I ended up going with.
- friendzis 5y ago
  > I wish ground source heat pumps were more affordable I don't think this will ever be the case. Water-to-water (ground source) and air-to-water (air source) heat pumps are effectively the same thing technically sans some tuning for temperatures, therefore the difference in cost of the heat pump itself is never going to be high. The cost difference is in installation costs. Air-to-water heat pump installation is as simple as mounting the external unit and routing a few pipes back to interior unit while water-to-water installation is routing the distributed heat exchanger, which is significantly more labor intensive even if you do not account for landscaping (e.g. done as part of greenfield development which will have landscaping done anyway).
smichel17 5y ago
The house I grew up in had a geothermal system (installed when my parents built the house). I was a bit young to know the precise details, but I believe the idea was that the ground loop merely heated or cooled (depending on the season) to the ground's ambient temperature, around 60ºF. From there, it was further heated using traditional methods. I think that meant a heat pump, as you mention, but it might have been oil. The energy savings in the winter (US-MA) was nice -- heating from 60 is a lot less energy than heating from 30 or below -- but the summer was the real reason I'll absolutely install geothermal in any house I build: basically free a/c. Not having to think about setting the thermostat for a relatively large house down to 72 (or even lower, if you want to freeze your tookus off) is so freeing.

by wffurr 5y ago

coryrc 5y ago

For the same cost we could install multiple air-source heat pumps at nearly the same efficiency. That's a way better tradeoff.

Johnny555 5y ago

I wish ground source heat pumps were more affordable, I asked my HVAC installer, he said I was looking at $30K+ including returning the yard to the state it was in before they trenched in the pipes. That's 3X the cost of the air source heat pump I ended up going with.

friendzis 5y ago
> I wish ground source heat pumps were more affordable I don't think this will ever be the case. Water-to-water (ground source) and air-to-water (air source) heat pumps are effectively the same thing technically sans some tuning for temperatures, therefore the difference in cost of the heat pump itself is never going to be high. The cost difference is in installation costs. Air-to-water heat pump installation is as simple as mounting the external unit and routing a few pipes back to interior unit while water-to-water installation is routing the distributed heat exchanger, which is significantly more labor intensive even if you do not account for landscaping (e.g. done as part of greenfield development which will have landscaping done anyway).

smichel17 5y ago

The house I grew up in had a geothermal system (installed when my parents built the house). I was a bit young to know the precise details, but I believe the idea was that the ground loop merely heated or cooled (depending on the season) to the ground's ambient temperature, around 60ºF. From there, it was further heated using traditional methods. I think that meant a heat pump, as you mention, but it might have been oil. The energy savings in the winter (US-MA) was nice -- heating from 60 is a lot less energy than heating from 30 or below -- but the summer was the real reason I'll absolutely install geothermal in any house I build: basically free a/c. Not having to think about setting the thermostat for a relatively large house down to 72 (or even lower, if you want to freeze your tookus off) is so freeing.