[audio:http://wamcradio.org/EarthWise/wp-content/uploads/2013/09/EW-09-12-13-Air-Pumps.mp3|titles=EW 09-12-13 Air Pumps]
Heat pumps are a special type of air conditioner that can not only cool your home by expelling heat to the outside, but can also heat your home by bringing heat back in. There are two types: air source and ground source.
Ground source heat pumps, also called geothermal heat pumps or geoexchange, transfer heat to and from a ground loop, which consists of pipes buried in the ground. Air source heat pumps use condensers with fans, which we often see next to or on rooftops.
The stable temperatures underground allows ground source heat pumps allows to operate efficiently both in the heat of summer and the depths of winter. Until recently, less expensive air source heat pumps were only used in moderate climates because they were ineffective at extracting heat from the outside air when it’s below about 40 degrees F.
New, variable speed compressor technology has changed the playing field. Now, air source heat pumps can operate in temperatures as low as -5 F, making them practical in the Northeast. The technology also reduces noise, and is now available from many heat pump manufacturers.
A friend recently outfitted his historic home with variable speed air source heat pumps. They were only slightly more expensive than a comparable air conditioning system. And by using heat pumps instead of oil, he cut his heating costs in half while reducing his carbon footprint.
If you’re considering installing or replacing your air conditioning, consider a heat pump instead.
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This piece was authored by Tom Konrad Ph.D. CFA. Tom also writes about green investing here for Forbes.
Photo, taken on April 12, 2010, courtesy of Paul Sullivan via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio. Support for Earth Wise comes from the Cary Institute of Ecosystem Studies in Millbrook, NY.