Friends of mine just replaced their traditional gas heating-cooling system with a geothermal system. The geothermal system utilizes the constant ground temperature to generate heat in the winter and dissipate heat in the summer, and results in virtually no CO2 emissions.

If you go 10-15 feet underground, the ground is pretty much always 53-55 degrees - year-round. A geothermal system includes about 1200 feet of water-filled tubes that are 15 to 125 feet underground (the tubes are installed using something called a directional bore, which threads the tubing underground without having to dig a trench or dig up the property). The water flowing through the tubing returns to the house at that ground temperature, and is then used by a heat pump to translate the temperature difference between the indoor air and the water to heat or cool the home.

And because the heat pump uses very little energy to operate, the systems dramatically reduce the energy consumption to heat and cool  home. AND, they generate essentially no CO2.

These systems cost 2-3 times more to install than a traditional furnace-A/C system, but will pay for themselves in 5-10 years through reduced utility costs. Obviously, like other alternative energy systems, geothermal is for someone who is thinking long-term!!

I spoke to someone who installs the systems, and he told me about a new subdivision going in in Hampshire IL, that will have geothermal systems for all the homes. The installer said that the systems are more cost-effective to install for new construction than for a retrofit, but are still expensive enough that they are pretty much only being used by some custom home builders. The production builders who are mostly interested in big homes for less money aren't thinking about long-term investments that will pay-off for the homeowner in a few years. But, maybe as the prices of gas and electricity keep going up, this type of system will become standard in new construction because people will start demanding it?