Our winters are too chilly for an air heat pump to work efficiently so I wondered if it could be installed in the basement, and insulate the floors. You would be using 55 degree air to extract heat for house and be sucking the geo thermal out of the walls and surrounding soil. I am in southern PA . Would the basement lose more than 10 degrees? We now have a hot water boiler with baseboard and domestic HW coil. In the summer the water heating seems very inefficient. Has anyone put an electric HWH in as a preheater. I could use off peak electric and turn it off in the winter when the boiler is on. I was thinking of a homemade solar preheater but it is too shady here.

Your basement idea would work for some amount of heat extraction. But what that amount is isn't trivial to calculate.

Have you looked at a geothermal heat pump?

They are generally noisy, so you would want the air to air heat pump in a sound deadened room.

Jere,

I know my hearing is not as good as it used to be but I have not had any clients complaining about noise from geothermal units.  Some of my clients have used these units since the late 1970's.  Surely, today the new units should be even quieter.  Do the geo manufacturers publish the noise levels?

I considered enclosing mine with a greenhouse type structure since it is on the S side of the house but would need to automate some openings for nighttime  and also provide good ventilation for summer cooling mode. 

Alton, I was referring to air to air heat pumps, not geo.

Haha no you dont want to put it in your basement for a multitude of reasons that dont deserve the time to go over them. Just get a heat pump with a 95%+ gas furnace backup. This way you will have A/C during the summer and you will be able to use the heat pump for heating when temps are above 35 or so.

Posted By jonr on 01 Aug 2010 09:31 AM
Your basement idea would work for some amount of heat extraction. But what that amount is isn't trivial to calculate.

Unless this house has nearly PassiveHouse levels of insulation, it's would be trivial to estimate that the air in the basement would drop well below 55F in the first hour of continuous operation though, eh? :-)

There simply isn't nearly enough surface area on the concrete/subsoil boundary to support the kind of heat flux that would keep the rest of the house warm at modest basement-air/subsoil delta-Ts,  if conventional (even way-better than code) levels of insulation are used.  If your house loses heat fast enough to require a large fraction of the output of a heat pump,  this approach is useless. (And if it doesn't, buying a heat pump is a waste of money.)