Geothermal systems use the stable temperature of the earth to heat or cool a house or building. They are also known as ground source heat pumps and instead of generating heat by burning fossil fuels they simply transfer heat from one location to another.
Evergreen installs closed loop geothermal systems, which circulate a water and antifreeze solution through plastic pipes buried beneath the earth's surface. During the winter, the fluid collects heat from the earth and carries it through the system and into the building. During the summer, the system reverses itself to cool the building by pulling heat from the building, carrying it through the system and dumping it to he ground. This process creates free hot water in the summer and delivers some hot water savings in the winter.
Ground source heat pumps are the most efficient way to heat or cool a building because there is no fuel to burn. They use electricity to run a circulator pump and a compressor. All ground source heat pumps that Evergreen installs are high efficiency with two stage compressors, ECM blowers and R-410A refrigerant. Ground source heat pumps are sized based on the heat loss and heat gain of a building, which must be carefully calculated. Sizing is in tons, where a ton of capacity is equal to 12,000 British thermal units (Btu's) per hour.
Ground loops can be installed into vertical borings, horizontal trenches or surface water bodies such as ponds and lakes. Ground loops are generally buried a minimum of four feet below the ground surface and are not visible.
Incentives to install residential geothermal systems are better than ever. Connecticut's utility companies provide rebates of $500 per ton up to a limit of $1,500 per address. In addition to the utility rebate, the American Recovery and Reinvestment Act (ARRA) provides a full 30% federal tax credit for geothermal systems installed after December 31, 2008.