Frequently asked Questions about Ground Source Heat Pumps (GHP)

Q: How effective is this underground system?

A: The buried pipe, or ground loop, is the most recent technical advance in heat pump technology. The idea to bury pipe in the ground to gather heat energy began in the 1940's. Only recently, however, have new heat pump designs and improved buried pipe materials been combined to make GHP systems the most efficient heating and cooling systems available.

Q: What is the efficiency rating of this type of system?

A: GHP systems are rated by measures of heating and cooling efficiency. When purchasing a GHP system, ask for an efficiency rating of 2.8 COP(h)/13 EER or greater.

Q: What are the environmental benefits of GHP systems?

A: GHP systems conserve energy, and because they move heat that already exists rather than burning something to create heat, they reduce the amount of toxic emissions in the atmosphere. They use renewable energy from the sun, and because the system doesn’t rely on outside air, keeps the air inside of buildings cleaner and free from pollens, outdoor pollutants, mold spores, and other allergens.

Q: Are GHP systems difficult to install?

A: Most units are easy to install, especially when they are replacing another forced-air system. This is known as a retrofit. GHPs can be installed in areas unsuitable for fossil fuel furnaces because there is no combustion and thus no need to vent exhaust fumes. Ductwork must be installed in homes without an existing air distribution system. The cost of installing ductwork can be assessed by your dealer or installer.

Q: Will my existing ductwork function with this system?

A: Yes, in most cases. Your dealer or installer will be able to determine ductwork requirements and minor modifications needed, if any.

Q: What changes in performance can be expected at freezing operating conditions?

A: A drop in soil temperature from 40 degrees F to 30 degrees F results in a loss of capacity and efficiency of about ten percent. At 30 degrees F, latent heat from moisture in the soil freezing adds considerably to the capacity of the system, allowing very successful performance of the systems in northern climates.

Q: Do soil freezing conditions create any problems?

A: Not if a system is properly designed and installed. The three to four foot depth allows the sun to melt the frozen soil during the summer. Adequate length per ton capacity prevents objectionable soil movement.

Q: what are the advantages and disadvantages of the horizontal and vertical installations, respectively?

A: Horizontal installations are simpler, requiring lower-cost equipment. However, they require longer lengths of pipe due to variations in soil temperature and moisture content, and installations can be adversely affected by extensive rainy weather. A larger area is usually required. Extensive hard rock may dictate a vertical installation, which requires highly trained operators for the drilling machines, but less pipe. Where land is limited, vertical installations or a compact Slinky (TM) (horizontal installation) can be ideal.

Q: Will an underground loop affect my lawn or landscape?

A: No. Research has shown that loops have no adverse effects on grass, trees, or shrubs. Most horizontal installations require trenches about six inches wide. Temporary bare areas can be restored with grass seed or sod. Vertical loops require little space and do not damage lawns significantly.

Q: Will I have to add insulation to my home if I install one of these systems?

A: Geothermal heat pump systems will reduce your heating and cooling costs regardless of how well your home is insulated. However, insulating and weatherizing are key factors in gaining the maximum amount of savings from any type of heating and cooling systems.

Q: Can these systems be used for commercial, industrial, or apartment requirements?

A: Yes. Many GHP systems are being installed using a multitude of systems hooked up to an array of buried vertical or horizontal loops. This simplifies zone control and internal load balancing.

Q: How does a GHP system heat water for my home?

A: Using what is called a desuperheater, GHPs turn waste heat to the task of heating hot water. During the summer, when the system is in a cooling mode, your hot water is produced free as a byproduct of the thermal process. In winter, with the heating mode, the desuperheater heats a portion of your hot water. Desuperheaters are standard on some units, optional on others. Stand-alone systems which will heat water all year around can be purchased.

Q: Can a GHP system be added to my fossil fuel furnace?

A: Yes. Called dual systems, they can easily be added to existing furnaces for those wishing to have a dual-fuel heating system. Dual-fuel systems use the GHP system as the main heating source, and a fossil fuel furnace as a supplement in extremely cold weather should additional heat be needed.

Q: Does this mean that in extremely cold climates additional heat sources are necessary?

A: All systems require an emergency back-up. Heat pumps can provide all the heat necessary even in the coldest weather. An economic analysis by your contractor should dictate what portion of the heat should be provided by the heat pump and by which auxiliary means.

Q: Are GHP systems guaranteed?

A: Nearly all GHP system manufacturers offer a warranty for major components that is equivalent to the warranties for conventional heating and cooling systems. Manufacturers of plastic pipe used for ground loops warrant their products for 25-50 years.

Q: What about comfort?

A: A GHP system moves warm air (90-105 degree F) throughout your home or business via standard ductwork. An even comfort level is created because the warm air is moved in slightly higher volumes and saturates the building with warmth more evenly. This helps to even out hot or cold spots and eliminates the cold air blasts common with fossil fuel furnaces.

Q: What are the advantages to an HVAC dealer?

A: GHP systems create a huge retrofit market not subject to wild fluctuations in housing construction. There is also ample opportunity for stable growth benefiting the dealer and his employees. In addition, these systems are relatively maintenance-free, requiring only regular filter changes. This means fewer maintenance and support calls. There is no outside equipment, so wear and tear is less.

Q: Who do I contact for more information?