[GSBN] ground source heat pumps
David Arkin, AIA
david at arkintilt.com
Wed Mar 18 12:45:23 CDT 2009
Hello Catherine, All:
Ground Source Heat Pumps (aka Geo-Exchange) are the most efficient way
to use electricity for heating and cooling. They are most cost
effective in climates (or poorly designed buildings) requiring both
heating and cooling.
Here's how it was described to me, in the simplest of terms:
Straight electrical resistance heating: 1 part electricity = 1 part
Air Source Heat Pump: 1 part electricity + 1 part energy from air = 2
parts heat energy
Ground (or Pond) Source Heat Pump: 1 part electricity + 3 parts
energy from constant temperature earth = 4 parts heat energy
Thus, the GSHP is twice as efficient as a condensing unit, and 4 times
more efficient than electrical baseboards, towel bars, or radiant.
Yes, these can be expensive, especially if your drilling costs are
high. If your water well was expensive due to rocks, etc., then this
probably won't be a good choice. If you're moving a lot of earth and
have the opportunity to bury horizontal coils under at least 6' of
earth, that could save the drilling cost. Pond loops are cheaper
still, if you have a pond (one large and deep enough to take the
Yes, these can be married with renewable energy systems, and this
combo is considered the 'cadillac' of options.
We've only used this once, in an institutional building. It's working
great. For any residential project it's been the first thing cut,
even if the project wasn't over budget. Investing in a better
envelope (passive design, highest quality windows, insulation and
weatherstripping) is the smarter expenditure, IMHO.
On Mar 18, 2009, at 10:16 AM, BuildersWithoutBorders wrote:
> Dear colleagues -
> Can someone shed some light on so-called geothermal heating systems,
> and their cost-effectiveness for a typical home?
> I imagine the pay-back in energy saved has something to do with how
> many heating degree days in a specific climate. But then, I
> understand they can also be reversed for cooling.
> This seems like an expensive technology that is dependent on
> electrical service... can it be powered by solar/
> Thanks for any insight offered.
> Catherine Wanek
> Builders Without Borders
> <mail at builderswithoutborders.org>
> GSBN mailing list
> GSBN at greenbuilder.com
* * * * *
Arkin Tilt Architects
Ecological Planning & Design
David Arkin, AIA, Architect
LEED Accredited Professional
CA #C22459/NV #5030
1101 8th St. #180, Berkeley, CA 94710
"There is no way to peace. Peace is the way."
— A. J. Muste
More information about the GSBN