5 ms·

From what I've heard, heat pumps with ground loop heat exchangers maintain a 450-500% efficiency rating all year round, regardless of how cold or hot it is outs

by ericd 5y ago

From what I've heard, heat pumps with ground loop heat exchangers maintain a 450-500% efficiency rating all year round, regardless of how cold or hot it is outside. Here's a variable speed one that claims COP of ~5: https://www.waterfurnace.com/residential/products/geothermal-heat-pumps/700a11 https://www.waterfurnace.com/residential/products/geothermal... (I think that's only when it's running at 30%, though, drops to 4.5 when at high speed).

Arubis 5y ago
Installing a ground loop is a _significant_ expense, oftentimes well beyond the reservation price for residential buyers.
- earleybird 5y ago
  In my neighbourhood, ground source is triple the cost of air source. Got quotes for both about 3 yrs ago. We don't have the option for horizontal so ground source would have been 3, 50 meter deep bore holes arrranged in an equilateral triangle 7 meters between points.
- ericd 5y ago
  Yeah, the ground loop is a really big chunk of the overall expense, I think it was $20k of the cost by itself for our most recent quote, but it's expected to last 50-100 years, so it's amortized over a loooong time period of significant energy savings and increased performance over an air-source heat pump. Home buyers probably won't properly account for that when you're reselling, since it's not visible in the same way a remodeled kitchen is, but hopefully they'll start to as it becomes more common and/or energy prices increase. Also, there are a lot of tax credits - 26% of the entire cost this year as a federal tax credit if you install this year (decreasing to 22% next year), and a number of state and local incentives bring the cost down significantly. And there are obviously financing options available. If you combine it with a large solar array, I think the biggest thing it brings you is reducing uncertainty about future bills - you're locking in your expenses, a little like what buying a house does vs renting.

by ericd 5y ago

Arubis 5y ago

Installing a ground loop is a _significant_ expense, oftentimes well beyond the reservation price for residential buyers.

earleybird 5y ago
In my neighbourhood, ground source is triple the cost of air source. Got quotes for both about 3 yrs ago. We don't have the option for horizontal so ground source would have been 3, 50 meter deep bore holes arrranged in an equilateral triangle 7 meters between points.
ericd 5y ago
Yeah, the ground loop is a really big chunk of the overall expense, I think it was $20k of the cost by itself for our most recent quote, but it's expected to last 50-100 years, so it's amortized over a loooong time period of significant energy savings and increased performance over an air-source heat pump. Home buyers probably won't properly account for that when you're reselling, since it's not visible in the same way a remodeled kitchen is, but hopefully they'll start to as it becomes more common and/or energy prices increase. Also, there are a lot of tax credits - 26% of the entire cost this year as a federal tax credit if you install this year (decreasing to 22% next year), and a number of state and local incentives bring the cost down significantly. And there are obviously financing options available. If you combine it with a large solar array, I think the biggest thing it brings you is reducing uncertainty about future bills - you're locking in your expenses, a little like what buying a house does vs renting.