Coefficient of Performance is the measure of heating efficiency. An index of 1.0 means for every one unit of electrical energy spent you get one unit of heat energy. An index of 6 means that for every one unit of electrical energy spent you get 6 units of heating energy. The higher the number, the more efficient the energy exchange.
Free Cooling is the term used to describe the process of utilizing the colder outside air to cool a building instead of operating an air conditioning unit. This can be done actively with a fan or passively with opening windows.
Geoexchange is the transfer of thermal energy from the earth to a building. We take heat from the earth by cooling the ground similar to how the back of a refrigerator is warm from taking heat out of the inside of the refrigerator. Most systems are reversible and can cool as well as heat. This should not be confused with Geothermal heat which is the hotter earth’s core temperature.
Greenhouse gases are gases in an atmosphere that absorb and emit radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. Common greenhouse gases in the Earth’s atmosphere include water vapor, carbon dioxide, methane, nitrous oxide, ozone, and chlorofluorocarbons.