Why install a ground-source heat pump?
A ground-source heat pump takes advantage of a renewable resource: the heat underground. Unlike outside air, the temperature of the earth, beginning just 5 to 10 feet below the surface, stays at about 50 to 60 degrees F year round. The same is true of ground water from subsurface aquifers, as well as water below the surface of lakes, ponds and rivers. You do not need a geothermal resource (hot water or steam) to take advantage of this technology. Ground-source heat pumps work well throughout PGE’s service area. They are a premium heating and cooling source that can cost considerably more than other options. Good applications can include:
How a ground-source heat pump helps you
- Homes needing energy-efficient heating and cooling
- Homes with access to ground water or surface water
- Homes with sufficient outside space for a buried ground loop
- Homes using forced-air or radiant hydronic wall registers
- New homes where radiant hydronic piping can be located in the floor or ceiling
Ground-source heat pumps are among the most energy efficient of all heating and cooling systems. 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
How a ground-source heat pump works
A geothermal heat pump uses the constant, below-ground temperature of soil or water to heat and cool your home. In winter, it pulls heat from the earth or water (1) and brings it inside, using a heat exchanger (2). In summer, the process reverses to cool your home. The system usually includes a ground loop of piping, a heat exchanger and a distribution loop inside your home. You also can install a traditional, ducted air supply instead of the inside distribution loop. Some systems also supply hot water, further increasing energy efficiency.
Hire an experienced contractor
These installations can be complex, so it’s critical 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).
The U.S. Department of Energy website has extensive information on how to buy an energy-efficient, ground-source heat pump (PDF).
*Source: U.S. Department of Energy