Earning the ENERGY STAR means products meet strict energy efficiency guidelines set by the US Environmental Protection Agency and the Department of Energy.

• ENERGY STAR qualified geothermal heat pumps use about 30% less energy than a standard heat pump.
• They are quieter than conventional systems.

Geothermal heat pumps (sometimes referred to as GeoExchange, earth-coupled, ground-source, or water-source heat pumps) have been in use since the late 1940s. Geothermal heat pumps (GHPs) use the constant temperature of the earth as the exchange medium instead of the outside air temperature. This allows the system to reach fairly high efficiencies (300%-600%) on the coldest of winter nights, compared to 175%-250% for air-source heat pumps on cool days.

As with any heat pump, geothermal and water-source heat pumps are able to heat, cool, and, if so equipped, supply the house with hot water. Some models of geothermal systems are available with two-speed compressors and variable fans for more comfort and energy savings. Relative to air-source heat pumps, they are quieter, last longer, need little maintenance, and do not depend on the temperature of the outside air.

A dual-source heat pump combines an air-source heat pump with a geothermal heat pump. These appliances combine the best of both systems. Dual-source heat pumps have higher efficiency ratings than air-source units, but are not as efficient as geothermal units. The main advantage of dual-source systems is that they cost much less to install than a single geothermal unit, and work almost as well.

Even though the installation price of a geothermal system can be several times that of an air-source system of the same heating and cooling capacity, the additional costs are returned to you in energy savings in 5–10 years. System life is estimated at 25 years for the inside components and 50+ years for the ground loop. There are approximately 50,000 geothermal heat pumps installed in the United States each year.

Take a Stand, Make a Differnce

Here’s a term you should know: Enhanced Geothermal Systems (EGS). These power systems create electricity by using the heat deep below the Earth’s surface. The government and Google.org (a great outfit) showed their support for this young technology by throwing a combined $100 million at it, and while that initial investment is only the beginning of what is needed, it shows that the technology is getting some much needed attention.

Perhaps a better explanation:

EGS is a baseload resource, meaning that unlike wind or solar power, it will operate all day/all year whether the sun is shining or the wind is blowing. Another advantage is that this type of power is essentially engineered into a closed system where the water used to run the turbines is recycled. Sounds game changing, huh.

Well as great as Enhanced Geothermal is, it is still a long way from large-scale, commercial deployment. It is reassuring to know, however, that we have money and brainpower flowing into these projects. And the combination of these renewable resources is the only way we can count on a bright future. A future where EGS counts on one of our oldest constants, Mother Earth.

Check out this report for an extremely detailed look at Enhanced Geothermal Systems (14mb pdf).