Improving home energy efficiency is no longer a trend — it’s mainstream. Scott is one of those people early on who built his home using a Geothermal (or “ground-source”) heating and cooling systems. A geothermal system uses the temperature of the ground to condition the air that is distributed through the house using conventional duct work. To transfer ground temperature to the home’s central air distribution system, a closed loop of narrow, flexible pipe is installed underground, vertically or horizontally. Eight feet underground, the temperature of the ground stays at about a steady 68 degrees. Conductive, non-toxic fluid is pumped through the pipe and is heated or cooled (depending on its temperature) by the constant temperature of the ground. When that fluid returns to the surface, it transfers its temperature to the air being blown into the home’s duct work.
Conventional, air-sourced heat pumps use the temperature of the ambient outdoor air, which is far less predictable and constant than underground temperatures. In winter, for instance, if the thermostat is set at 72 degrees, the heating coils in the pump only need to boost the incoming ground-conditioned, 68-degree fluid by a few degrees to achieve the desired temperature. The outdoor air temperature that day, however, is likely much colder, which requires far more energy from the pump’s heating coils to warm it sufficiently. Because this type of ground-source system requires far less supplemental heating or cooling measures to achieve desired indoor temperature and comfort levels, it uses less energy. In turn, there’s less wear and tear on the heat pump, allowing it to operate at optimum efficiency for a longer period of time and with less maintenance.
Current benefit: Until 2016, the Federal Government is offering a 30% tax credit on geothermal systems with no upper limit. This covers both the cost and installation of the units. These credits apply to both new construction and existing homes. The cost to install a geothermal system and the savings vary. Hypothetically, if a Geothermal system costs twice as much as a conventional air-sourced system, and cuts the monthly energy use and cost in half, there will be a substantial return on investment within a few years.
