In most climates, the ground is warmer than the air temperature during the winter and cooler than the air temperature in the summer. 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.