1.   But there is none of that with geothermal systems.

2.   Curiously, a lot of the featured homes had geothermal heating systems, which are essentially heat pumps supplied by water circulated in very deep wells.

3.   It is easier to put a geothermal system in when a new house is being constructed, but retrofitting older homes is possible.

4.   Rainwater and household waste water are collected and reused for irrigation, and heat and air conditioning come from a silent underground geothermal system.

5.   The heat a geothermal system giveth, it also taketh away.

6.   What makes an Energy Star Home unique, and energy efficient, not even counting the geothermal heating system?

7.   Yinger padded into the kitchen in his socks, over tiles warmed by a geothermal system, to check on the curry soup simmering on the stove.

8.   A growing number of people are bypassing natural gas and heating oil in favor of geothermal systems.

9.   Geothermal systems are basically electric-powered heat pumps connected to piping buried deep in the ground, laid on a lake bottom or run down a well.

10.   Some bypassing natural gas and heating oil in favor of geothermal systems.