Using the earth to reduce your electric bill

This St. Louis couple turned to geothermal when their air conditioning system started to fail. Their heating and cooling costs fell by more than half, they estimate.

The heat pumps extract energy from the ground, where temperatures stay fairly stable, generally from 45 degrees to 75 degrees Fahrenheit, according to the California Energy Commission.

The systems aren't cheap - $7,500 for a system that can handle a typical home, plus drilling costs of $10,00 to $30,000, depending upon terrain - but the CEC says the investment can be recouped in five to 10 years.

In some cases, a tax credit might be available to cut the cost. Here's a detailed analysis from the CEC.

The San Joaquin Valley Clean Energy Organization is a nonprofit dedicated to improving our region's quality of life by increasing its production and use of clean energy. The SJVCEO works with cities and counties and public and private organizations to demonstrate the benefits of energy efficiency and renewable energy throughout the eight-county region of the San Joaquin Valley.