Geothermal Home Heat Pumps and Energy Systems

In the USA the most popular of geothermal energy is the use of heat pumps. Geothermal is essentially extracting using air pumped through pipes in the earth. For heat pumps or heat exchange systems these can be as little as 6 feet under the earth’s surface. When used to generate electricity they are typically over 1,500 feet into the earth. The reason for heat pumps to so shallow is that the air temperature just a few feet below the surface typically stays in tight temperature range between 50F and 60 F or 10C and 16 C. This is very similar to why caves are always so cold. When used to generate electricity the deeper distance have a much hotter temperature.

Geothermal energy systems will bore two pipes deep in the earth and fracture the rocks between them. They will then inject liquid carbon dioxide into one pipe and the other pipe will return this as a gas. This will then spin a turbine to generate the electricity. This technology has a lot of potential but also faces a lot of regulatory hurdles to be implemented, though hopefully that will change some in the future. Currently the USA has the largest amount of electricity of any country with over 3,000 MW but that only accounts for 0.3% of our total energy consumption. There are some downsides to this technology, it does have some CO2 emissions and does have some other pollutants and toxic chemicals associated with it. This technology will be part of any renewable energy plan for the future.

Another form of geothermal energy is the use of heat pumps. These systems can be much smaller and designed for single homes. They use some form of a refrigerant to cool or head the liquid which is then used to do the same to the incoming air in the house or facility. This air is then blown through the facility when it is warm out as its temperature will be below the typical temperature used for Air conditioning or when it is cold a heater will then heat the air that is already warmer than the outside air. This has many advantages as this air is closer to the desired temperature in both instances a lot less energy is needed to heat or cool the air to a comfortable temperature. This produces substantial savings once the initial installation is paid for. Typical systems will save over 40% in heating and 70% in cooling costs.

The main drawback for geothermal heat pumps is the large installation cost. Prices vary depending on the source with some as low as $8,000 and some as high as $20,000 for detached homes in the USA. A realistic average is probably about $14,000 for the installation of the system. In the USA you can expect to recover your costs in 4 years if you use electric heating, 5 years using heating oil or 12 years using natural gas. If you are using electricity to heat your home this is probably a viable alternative to be used. A typical system should last well over the time to recoup costs on even natural gas systems. The technology is relatively new but many that were installed over 20 years ago are still operating and some installations have 25 to 50 year warranty.