Cohousing-L Mailing List: Ground-source Heat Pumps

[Sharon Villines (sharon]

Fast Company has a good article on a program in Massachusetts in which almost 
all homes are switching to geothermal energy. By doing it as a community they 
are saving a bundle on installation and will next save a bundle on energy. 

https://www.fastcompany.com/90907992/in-this-massachusetts-neighborhood-nearly-every-home-is-switching-to-geothermal-energy

After our installation by a not to reputable company, we discovered that we 
were greatly over-installed. A major cost is drilling holes several hundred 
feet into the ground for the loops that move water down to where it is warmed 
or cooled to 55 or so degrees. The best installations use one loop for as many 
households as necessary — not one loop per household. In Massachusetts by 
converting whole neighborhoods to geothermal, they can install the best balance 
of loops for  “the block” and join them together.

It’s very easy after having ground-source geothermal to forget how much money 
it saves us year-round. Now we have solar panels providing the electricity for 
the common house and outdoor lighting so it is essentially free. The 
maintenance and repair of the system is probably comparable to what we would be 
doing with any other kind if heat.

But for 825 SF, with exposure on three sides including morning and afternoon 
sun, my electric bill is still in the range of $45-50 every month. That 
includes working at home, a set temperature of 74 degrees, washer/dryer, 
dishwasher, at least one screen on, and ceiling fans. Last year my bill jumped 
to $60 a month for no good reason, but I forgot to follow up and find out why. 
This year it went back down to $44 — ah! Error in calculating budgeted use.

It was hard to pay upfront and we have learned by having one of the worst 
installations ever designed but in the long run it is been worth it. An office 
building near by had calculated that their new system would pay for itself in 
seven years but actually paid for itself in four. That was a number of years 
ago — I don’t know what current numbers are.

Sharon
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Sharon Villines
Takoma Village Cohousing, Washington DC
http://www.takomavillage.org