On Mar 7, 10:34*am, Ohioguy wrote:
* *The heat pump in basement idea is interesting, but would not work
unless you had some way to increase the surface area for heat transfer.
* For example, if you had buried a network of pipes in the floor before
pouring the cement, you could circulate water through there, and then
have it go through a radiator. *Behind the radiator you could have a
squirrel cage/centrifugal blower. *Your only cost to maintain the air
temp in the basement would be for an efficient water pump and efficient
squirrel cage blower. *This could make a heat pump very efficient.

* *Of course, if you have that setup, it would be much better to simply
use a heat pump designed to directly work with the water or whatever
fluid is in the pipes. *That would be a geothermal system.

It's an interesting idea to use the basement as a heat source. But
as
you point out, the real question is how
much the basement temperature will drop. Dropping that temperature
is going to take some heat away from the house through colder floors,
more heat loss through basement ducts, etc.

And another big issue I see is summer. Almost all heat pumps also
serves as AC. So, in the summer, you're raising the basement
temperature and again, how much is the key question. That would
obviously depend on the size of the basement. Large, open, full
basement would be the best case. Even then, I think it's highly
questionable.