Geothermal heat pumps
You hear a lot of talk about solar power these days, but you might be surprised to learn that one of the most promising solutions to high heating and cooling bills isn’t up in the sky, but buried deep under your lawn. Super-efficient Geothermal Heat Pumps provide clean, quiet heating and cooling while cutting utility bills by up to 70 percent.
Ground temperatures are a constant 55 degrees all year no matter what the weather is like. Geothermal works because the ground beneath our feet is warmer than the outside air in the winter and cooler in the summer. Inserting a series of small pipes into the ground allows heat to be transferred to and from your home. In this process heat is not created, it is transported therefore no fuel is burned.
There are 2 Basic Parts to a Geothermal System
- Heat Pump – the inside unit known as the heat pump
- Ground Loop – underground pipes which connect to the heat pump
The underground pipes, called a ground loop, circulate water which absorbs the heat from the earth and returns it to the indoor heat pump. The heat pump extracts the heat from the liquid then distributes it throughout your home as warm air. With the heat removed, the water is re-circulated to collect more heat from the ground. In this case, the loop water is warmer when it comes into the home than when it goes back into the earth since the heat is being removed.
The indoor heat pump takes the hot air from your home and removes the heat. This leaves behind cool air to be distributed through your vents as air-conditioning. The removed heat from the air is rejected into the earth through the ground loop. In this case, the water is warmer leaving the home then when it returns since heat is rejected into it.
This is not a new technology, in fact in many European nations geothermal heating and cooling is the standard. In Sweden and Switzerland, more than 75% of new homes have geothermal. The EPA has acknowledged geothermal systems as the most energy-efficient, environmentally clean, and cost-effective space conditioning systems available.
That’s why it takes only 1 kilowatt-hour of electricity for a geothermal heat pump to produce nearly 12,000 Btu of cooling or heating. (To produce the same number of BTUs, a standard heat pump on a 95-degree day consumes 2.2 kilowatt-hours.) Geothermal systems are twice as efficient as the top-rated air conditioners and almost 50 percent more efficient than the best gas furnaces, all year round. Another advantage is that there’s no need for a noisy outdoor fan to move air through the compressor coils. Geothermal units simply pump liquid, so they can be parked indoors, safe from the elements.
A typical 2,000-square-foot home setup could cost as much as $25,000 to install, depending on soil conditions and how much digging and drilling is involved. A house on a big lot, for instance, might be able to use pipes laid horizontally in long, 4-foot-deep trenches. Houses on small lots or rocky ledges could require three or four holes drilled about 300 feet straight down, a much more costly process. Time of payback depends on local utility rates, excavation/drilling costs, how well your house is insulated, the efficiency of the model you choose, as well as tax credits and utility rebates.
A 30% Federal tax credit for the installation of a ground source heat pump (geothermal system) is available. This Tax credit is available through the end of 2016. ‘Qualified Geothermal Heat Pump Property’ means any equipment which:
- Uses the ground or groundwater as a thermal energy source to heat the dwelling unit or as a thermal energy sink to cool the dwelling unit, and
- Meets the requirements of the Energy Star program which are in effect at the time the equipment is installed (call for details). Labor costs associated with the installation of the geothermal heat pump property and any associated materials (piping, wiring, ducts, etc.) are included. The residence does not have to be the primary residence.
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