Ground Source Heating
Geothermal heating and cooling uses the stable (55 degrees Fahrenheit) temperature of the Earth, or on groundwater in a well, along with an electric heat pump. Water is pumped through tubes underground or from a well. Throughout the winter, the water is warmer than the outside temperature, so the heat pump “extracts” heat from the water to distribute throughout the building, and the now-cooled water is returned to the earth to be rewarmed. The system is reversed in the summer, with the heat pump drawing hot air out of the building, and sending warmed water into the earth to be chilled.
There are several types of Geothermal Heat Pump systems. Which one is right for me?
Most installations use open-loop systems, in which groundwater is pumped from a drilled well through a heat pump, transfers heat into the building, and is pumped back into the well. Closed-loop systems circulate a heat-transfer fluid through coils of underground tubing in order to move heat to or from the ground.
Choosing a system appropriate for the physical characteristics of your property requires the design expertise of a geothermal contractor.
How can I calculate the cost of the system, and my expected energy savings?
Geothermal systems save on your heating and cooling operating and maintenance costs. Some system investments can be recouped in as little as two years and because the energy savings usually exceed payment on the system.
The price range to purchase and install a GHP system is widely variable. A well constructed 2,000 square foot building may typically require a four ton geothermal heat pump system. A standard water-to-air heat pump with ductwork may range from $3,800 to $5,000 per ton range for the “inside” geothermal equipment—about the same cost as a fossil fuel based heating and air conditioning system. This range varies because of construction variables, e.g. ductwork, plumbing and electrical requirements. A more costly, but maximum comfort, radiant floor system with summer fan coils driven by water-to-water geothermal heat pump has been termed “a comfort marriage made in heaven.” This type system can be in the $6,000 to $8,000 per ton or higher range.
Are geothermal systems hard to maintain?
Because GHP systems have relatively few moving parts, and because those parts are sheltered inside a building, they are durable and highly reliable. The underground piping system often carries warranties of 25 to 50 years, while the heat pumps often last 20 years or more.
GHPs have no outside condensing units like air conditioners, so there’s no concern about noise outside. A two-speed GHP system is so quiet inside a house that users aren’t able to hear when it’s operating and there are no telltale blasts of cold or hot air.
How safe are geothermal systems?
GHP systems are both safe and protected. With no exposed equipment outdoors, children or pets cannot injure themselves or damage exterior units. GHPs have no open flame, flammable fuel or potentially dangerous fuel storage tanks.
What about comfort?
A GHP system moves warm air throughout your home or business via standard ductwork. This creates a stable comfort level because the warm air is moved in slightly higher volumes and saturates the building with warmth more evenly. This helps even out hot or cold spots and eliminates the cold air blasts common with fossil fuel furnaces.
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