This example shows a deep, vertical ground loop placement.
Photo by WaterFurnace
Question: I have an old propane furnace and central air conditioner in my home. I was thinking of replacing them with a geothermal heat pump. What do I need to know?
Answer: A geothermal heat pump is an extremely efficient way to heat and cool your home with a single unit, but the cost of installing the system is much higher than the cost of installing a traditional air-source heat pump, and not every home has the proper soil needed to make geothermal a viable option.
Geothermal heat pumps use liquid-filled piping buried underground in place of the outdoor condenser unit found on air-source heat pumps. Since the ground stays at a fairly constant temperature year-round, this is an extremely efficient way to disperse heat in the summer and absorb heat in the winter, provided your lot has the appropriate space and terrain.
During winter, the heating output of a geothermal system does not drop as it gets colder outdoors, and homeowners rarely have to rely on the expensive backup electric resistance heating, but the real efficiency advantages are seen in the summer. In cooling mode, heat pumps have an energy efficiency ratio (EER) as high as 41. This is more than twice as efficient as the best new air-source heat pumps and central air conditioners.
The natural efficiency of a geothermal heat pump can be enhanced by upgrading to high-end variable-speed compressors and blowers that allow the system to respond to thermostat settings for maximum comfort. By constantly varying the heating or cooling output and blower speeds, these systems can run in longer, slower and quieter cycles to achieve desired temperature and humidity levels.
The next step down in comfort and efficiency is a model with a two-stage compressor. Most of the time, it runs at the lower output speed. When it cannot efficiently heat or cool your house to the desired thermostat setting, it automatically switches to the higher speed.
Another option to consider if you decide to install a geothermal system is a desuperheater. This upgrade traps waste heat and diverts it to your water heater, lowering your utility bills even more.
Even though the installed cost of a geothermal heat pump system is much higher—the total cost will vary depending on the type of ground loop needed—there is a 30-percent federal tax credit available on systems installed by the end of 2016. Homeowners who can afford the upfront costs of a geothermal system can also expect to make back the price difference through energy savings over the life of the unit.
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The following companies offer geothermal heat pump systems:
Climate Master - (877) 436-6263
Econar GeoSystems - (800) 432-6627
Hydro-Temp - (800) 382-3113
WaterFurnace - (800) 436-7283