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Geothermal heat pumps are one of two efficient options.
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Air source heat pumps are another efficient option.
Question: My old heating and cooling system must be replaced. With high energy costs and future energy price volatility, how can I determine the best way to go?
Answer: Your heating and cooling system is a long-term investment, one that you’ll be living with for 20 years or more. Calculating the “best” energy source over its life is difficult because the costs of heating fuels such as natural gas, propane and heating oil have shifted dramatically over the past decade and are likely to shift again.
Your local electric cooperative works hard to make sure you have reliable, affordable electricity and given the climate of South Carolina, modern air-source or geothermal heat pumps make good sense because a single unit can heat and cool your house efficiently.
A standard air-source heat pump is basically a central air conditioner with a few extra parts. The outdoor unit looks exactly the same as a central air conditioner. It is called a heat pump because it literally pumps heat out of your house (in cooling mode) or into your house (in heating mode) to or from the outdoor air.
Among central heating and cooling systems, geothermal heat pumps provide the highest efficiency and lowest year-round utility bills. While geothermal heat pumps have much higher installation costs (due to the need to place loops, or tubing, underground), a 30 percent federal tax credit—available through the end of 2016—can help lower the initial cost of a new system in your primary residence.
The primary advantage of installing a heat pump of any kind is it can provide year-round savings and shorten the payback period for your new system.
Question: Are portable heat pumps a reliable alternative to space heaters or window air conditioning units?
Answer: Portable heat pumps are free-standing units designed for indoor use, and they can be used to heat a single room in winter or cool it in summer. Used properly, they can be an efficient choice, but they are not a substitute for a good central heating and cooling system.
I use a portable heat pump in my home office, and in heating mode it can produce 11,000 Btu per hour. This is much more heat than a standard electric space heater can generate using the same amount of electricity. In cooling mode, my portable heat pump produces 14,000 Btu per hour of cooling, an amount comparable to a window air conditioner.
Portable heat pumps like those from Soleus Air are often mounted on casters so they can be easily rolled from room to room, but they are limited by the fact that they must be vented to a window in order to work properly. Most operate on standard 120-volt electricity, so they can be plugged into any wall outlet.
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What's new in heat pumps, August 2011
Geothermal heat pumps, February 2010