Geoexchange Helps You Bury Your Energy Costs

My basement den is often my favorite room in the house. It's cool enough during the dog days of summer that I can actually feel the temperature drop as I walk down the stairs from the ground floor. Yet during the winter it's still temperate enough to feel cozy.

This is the working theory behind geoexchange heating and cooling systems. They're also sometimes called ground-source heat pumps. 

The idea is that regardless of whether you live in a cooler or warmer area, the air underground remains a relatively steady temperature -- 45-50 degrees in the northern U.S. and 50-70 degrees down south, according to Greenbuilder.com . If you can push this ambient temperature up into your home, you can reduce or even eliminate the need to use air conditioning or fossil-fuel-based heat.

These days, that can translate into major savings -- and a good conscience for reducing greenhouse gases from burning fuels and using an alternative to drawing electricity from a power plant. 

I'm no engineer, so if you want the technical specs for how it works, check out Wikipedia's very good explanation or Grist's layman's discussion of it.

Basically, a contractor you hire digs several holes in the ground -- 100 feet or so down -- for pipes and then installs an electric pump that pushes air or water down to be warmed during the winter or cooled during the summer. 

It sounds exotic, but it's an option that's becoming more common in both new and existing homes. They're used in all 50 states, according to National Renewable Energy Laboratory. The Energy Information Administration reports that sales of these pumps were up 33% in 2006 from a year earlier.