Heat Pumps

The most efficient method of converting any source of heat is the heat pump. This device is similar to the compressor found in refrigerators and freezers. It works by capturing the heat gained or lost in the process of compressing or decompressing various types of gases, such as freon. The heat pump can be used to heat the house during the winter and cool the house in the summer. Its maximum heating efficiency is when the outside air is in the high 40's and 50's. At temperatures below 35 degrees, the heat pump relies on a backup heating system, such as electric resistance heat. The installation of heat pumps is approximately three times more expensive than gas or oil furnaces and the required ducting systems need to be somewhat larger than other forced air heating systems. Heat pumps also require more frequent and somewhat more costly service than other furnaces. Service for heat pumps is recommended on an annual basis with costs ranging from $100-$800 per year.

Article: 
Heating Your Home