from Jim in Racine, WI:
#295
I am building a new home and planning to insulate the walls with closed cell polyurethane. I am also interested in a geothermal heating system but my building contractor has indicated that with the insulation we are planning to use, the incremental benefits of a geothermal heating system would not justify the additional cost. Is this true?
Geothermal may not be cost-effective in this case.
Reducing the heat loss/heat gain of the building shell (outer structure of a building) by effective air sealing and high R-value (indicates insulation's resistance to heat flow) insulation is the correct first step in controlling energy costs. While you only mentioned how you intend to insulate the walls, it seems to me that you are concerned and motivated to carry that efficiency mentality throughout the rest of the building shell. With that assumption, I would tend to agree with your builder. It could take many, many years to re-coup the cost of a geothermal system.
There are plenty of (more traditional) “plug-n-play” heating/cooling systems with reliable track records for you to choose from that are considerably less expensive to install than geothermal systems. As an example, there are hybrid systems that incorporate high efficiency gas furnaces and air conditioning systems with very efficient air source heat pumps. It would be worth your time to investigate these systems. One important feature to look for is electronically commutated motors (ECM) that run the air handlers for distributing heated/cooled air. This technology is considered state of the art and these motors are extremely quiet and use a fraction of the electricity as compared to split capacitor motors. There are also high efficiency (over 90% efficient) gas water heaters now available as well.
Because you’re building a new home, another avenue for you would be to engage the services of a consultant partnering with the Focus on Energy New Homes Program. Through computer modeling, you can compare the projected energy costs with respect to the intended building shell, the orientation (to the sun) on your building site, and various equipment scenarios. Contact Focus on Energy to acquire a list of consultants throughout the state.
Published Friday, June 19, 2009