Ground-source heat pumps are among the most energy efficient of all heating and cooling systems. You do not need a geothermal resource to take advantage of this technology. They work well throughout the PGE service area. The advantages of ground-source heat pumps include:
- Use up to 72 percent less energy per year, compared to electric resistance heating with standard air conditioning*
- Efficiencies of 300 to 600 percent on the coldest winter nights, compared to 175 to 250 percent efficiency for a standard air-source heat pump*
- Zero emissions
- Embraced by LEED™ (Leadership in Energy and Environmental Design) and other green building organizations
- Qualify for a PGE rebate, an Oregon tax credit and a federal energy tax credit. The federal tax credit is 30 percent of installed cost, with no upper limit.
How a ground-source heat pump works
Unlike outside air, the temperature of the earth, beginning just 5 to 10 feet below the surface, stays at about 50 to 60 degrees year-round. The same is true of ground water from subsurface aquifers, as well as surface water from lakes, ponds and rivers.
In winter, a ground-source heat pump extracts heat from the ground or water and moves it inside to heat your home. During the summer, it removes heat from your home and transfers it to the cooler ground or water. Some systems also produce domestic hot water, further increasing energy efficiency.
The system usually includes a ground loop of piping, a heat exchanger, and a distribution loop inside your home. You will need sufficient outside space for the ground loop or access to ground water or surface water. Interior space heating and cooling often is provided by forced-air or radiant hydronic wall registers. New homes offer more flexibility and can take advantage of radiant hydronic piping located in the floor or ceiling.
Hire an experienced contractor
It’s important to use a qualified licensed contractor with experience in ground-source heat pump installations. The Oregon Department of Energy maintains a statewide listing of tax-credit certified technicians (PDF).
Purchasing advice
The U.S. Department of Education website has extensive information on how to buy an energy-efficient ground source heat pump (PDF).
*Source: U.S. Department of Energy