GHPs are efficient and, in some climates, can be used with no backup year round because the heat source remains at a relatively moderate temperature all year. It is generally measured in feet or meters. The amount of heat required to raise by one degree the temperature of a unit mass of a substance. A device, such as a coiled copper tube immersed in a tank of water which is used to transfer heat from one fluid to another through a separating wall. HEAT GAIN .
HEAT LOSS .
An unwanted decrease in the amount of heat contained in a space. HEAT PUMP . This process causes the source to cool and the sink to become warmer. Like an air conditioner or refrigerator, a heat pump moves heat from one location to another. In the cooling mode, heat pumps reduce indoor temperatures in the summer by transferring heat to the ground.