PROTECT YOUR INVESTMENT: KEYS TO A SUCCESSFUL GEOTHERMAL SYSTEM

A question to ask yourself when speaking with a geothermal contractor: "Is this contractor selling the equipment or the whole design and installation of a geothermal system?"

A few key factors essential for ensuring a proper working geothermal system:
1. Selecting a qualified contractor
2. Equipment selection & sizing
3. Loop field type & sizing
4. Duct sizing
5. Radiant systems design & application
6. Controls and operation.

PIPING
Special thick but flexible piping is used in geothermal installations. The most commonly used type of pipe is high quality, high density polyethylene. All below-grade connections must be made by heat fusing, which yields connections stronger than the pipe itself and without any threads. All installations must be purged to remove construction debris, flushed to remove air, and pressure tested (to 100 PSI) before backfilling or grouting.

SIZING
Numerous studies have shown that residential heat pumps are often sized too large. Heat pumps that are too large waste energy and do not provide proper humidity control. Where heating needs are much greater than cooling needs, advanced heat pumps (see above) can improve Summer comfort. Massmann Geothermal & Mechanical uses detailed information about your home as well as their experience to recommend the right type of unit and loops for your home.

PURCHASE AND INSTALLATION
As in the case of all major decisions, choosing a geothermal heating and cooling system requires some careful consideration to insure that the consumer receives the highest quality system and installation. The Geothermal Heat Pump Consortium (GHPC) offers the following guidelines:

1. Ratings and certification: The Air-Conditioning and Refrigeration Institute (ARI) is a non-profit organization that certifies performance of residential and small commercial geothermal equipment. For equipment classes rated by ARI, the GHPC suggests that consumers look for the ARI seal. (ARI does not rate large, commercial geothermal equipment greater than 135,000 Btu/hr).

2. Warranties: Manufacturers' terms of warranty vary. To assure a high quality installation, consumers should seek a performance guarantee on the installed system, as opposed to coverage limited to the heat pump itself.

3. Sizing: Numerous studies have shown that heat pumps are often sized too large. For maximum efficiency, heating and cooling loads should be carefully determined. The actual unit size should be within 15 percent of the calculated load. Heat pumps that are too large waste energy and do not provide proper humidity control.

4. Design: Residential system design is straight-forward, but the most satisfactory results are obtained with experienced contractors. Aspects to consider include careful duct design and installation in which ducts are kept in conditioned spaces and are permanently sealed; high quality insulation, glazing, and other envelope features to minimize loads and reduce air infiltration; and careful matching of heat pump and earth connection capacity to building load. It may be advantageous to specify two-speed or variable speed systems where heating requirements are much greater than cooling, to assure good humidity control. Finally, the contractor should examine ways to use the geothermal system to provide hot water.

5. Installation: Proper installation is a key to success. The GHPC recommends that consumers employ experienced contractors who will provide the names of customers with comparable systems.