Frequently Asked Questions
Geothermal Basics
Geothermal Heat Pumps
In the Loop
What Every Owner Should Know
Geothermal Thermal Basics
What does geothermal mean for the environment?
Geothermal systems work with nature, not against it. They emit no greenhouse gases, which have been linked to global warming, acid rain and other environmental hazards. WaterFurnace provides an earth-loop antifreeze which will not harm the environment in the unlikely event of a leak. And much of the WaterFurnace product line uses R-410A, a performance-enhancing refrigerant that will not harm the earth's ozone layer.
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How does a geothermal heating & cooling system work?
Outdoor temperatures fluctuate with the changing seasons but underground temperatures don't. Four to six feet below the earth's surface, temperatures remain relatively constant year-round. A geothermal system, which typically consists of an indoor unit and a buried earth loop, capitalizes on these constant temperatures to provide "free" energy. In winter, fluid circulating through the system's earth loop absorbs stored heat and carries it indoors. The indoor unit compresses the heat to a higher temperature and distributes it throughout the building. In summer, the system reverses, pulling heat from the building, carrying it through the earth loop and depositing it in the cooler earth.
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How efficient is a geothermal system?
A geothermal system is three to four times more efficient than the most efficient ordinary system. Because geothermal systems do not burn fossil fuels to make heat, they provide three to four units of energy for every one unit used to power the system. Return To Top
Do geothermal systems require much maintenance?
No. Geothermal systems are practically maintenance free. When installed properly, the buried loop will last for generations. And the other half of the operation--the unit's fan, compressor and pump--is housed indoors, protected from the harsh weather conditions. Usually, periodic checks and filter changes are the only required maintenance. Return To Top
Geothermal Heat Pumps
Are all geothermal heat pumps alike?
No. There are different kinds of geothermal heat pumps designed for specific applications. Many geothermal heat pumps, for example, are intended for use only with higher temperature ground water encountered in open-loop system. Others will operate at entering water temperatures as low as 25°F, which are possible in closed-loop systems. Most geothermal heat pumps provide summer air conditioning, but a few brands are designed only for winter heating. Geothermal heat pumps also can differ in the way they are designed. Self-contained units combine the blower, compressor, heat exchanger and coil in a single cabinet. Split systems (such as the WaterFurnace ES Split) allow the coil to be added to a forced-air furnace and utilize the existing blower.
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Will the minimum entering water temperature affect which geothermal heat pump I buy?
Yes. If you have an open loop system, your entering water temperatures (EWTs) may range from the 70s in the southern United States to the 40s in Canada. All heat pumps can handle temperatures in the moderate-to-warm range. A closed loop system, on the other hand, may encounter EWTs below freezing. Not all geothermal heat pumps will operate efficiently at those temperatures. It's important to know that EWTs at which your heat pump will operate most efficiently. Return To Top
In The Loop
Do I need to separate earth loops for heating & cooling?
No. The same loop works for both. To switch heating to cooling, or vice versa, the flow of heat is simply reversed. Return To Top
What type of loops are available?
There two main types: open and closed. Return To Top
What is an open loop system?
An open loop system uses groundwater from an ordinary well as a heat source. The groundwater is pumped into the heat pump unit where heat is extracted and the water is disposed of in an environmentally safe manner. Because groundwater is a relatively constant temperature year-round, wells are an excellent heat source. Return To Top
How much groundwater does an open loop system require?
The water requirement of a specific model is usually expressed in gallons per minute (g.p.m.) and is listed in the unit's specifications. Generally, the average system will use 1.5 g.p.m. per ton of capacity while operating, but the amount of water required depends on the size of the unit and the manufacturer's specifications. Water Source Heating & Cooling will provide this information. Your well and pump combination should be large enough to supply the water needed by the heat pump in addition to your domestic water requirements. You probably will need to enlarge your pressure tank or modify your plumbing to supply adequate water to the heat pump. Return To Top
What do I do with the discharge water?
There are a number of ways to dispose of water after it has passed through the heat pump. The open discharge method is the easiest and least expensive. Open discharge simply involves releasing the water into a stream, river, lake, pond, ditch or drainage tile. Obviously, one of these alternatives must be readily available and have the capacity to accept the amount of water used by the heat pump before open discharge is feasible.
A second means of water discharge is the return well. A return well is a second well bore that returns the water to the ground aquifer. A return well must have enough capacity to dispose of the water passed through the heat pump. A new return well should be installed by a qualified well driller. Likewise, a professional should test the capacity of an existing well before it is used as a return. Return To Top
What Every Owner Should Know
Can a geothermal heat pump be added to my fossil fuel furnace?
Split systems easily can be added to existing furnaces for those wishing to have a dual-fuel heating system. Dual-fuel systems use the heat pump as the main heating source and a fossil fuel furnace as a supplement in extremely cold weather if additional heat is needed. Return To Top
Do I need to increase the size of my electric service?
Geothermal heat pumps don't use large amounts of resistance heat so your existing service may be adequate. Generally, a 200-amp service will have enough capacity and smaller amp services may be large enough in some cases. Your electric utility or contractor can determine your service needs.
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How long is the payback period for a geothermal system?
To figure this accurately, you must know how much you'll save each year in energy costs with a geothermal system as well as the price difference between it and an ordinary heating system and central air conditioner.
As an example: If you'll save $700 per year with a geothermal system and the price difference is $2,000, your payback will be less than three years. If you install a geothermal system in a new home, the monthly savings in operating costs generally will offset the additional monthly cost in the mortgage, resulting in an immediate positive cash flow. Return To Top
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