Below are several resources to help you compare your energy options. Each is available as an Adobe PDF.

What is Coefficient of Performance (COP)?
The COP is how efficiences of heat pump systems are rated. It relates to the number of energy units produced for each unit used. For instance if a geothermal heat pump has a COP of 3.5, for every $1.00 of energy used to run it, it will produce $3.50 worth of heat energy in return.