Air Handler: Portion of system that moves the cooled or heated air throughout the home. This is sometimes handled by the furnace.
BTU: Stands for British Thermal Unit. This measures the amount of heat required to raise or lower the temperature of one pound of water one degree fahrenheit. In heat pumps and furnaces it refers to the amount of heat output of a unit.
Compressor: The compressor is the heart of the system, and acts as a pump which recirculates the refrigerant from the outside (condenser) to the indoor evaporator coil.
Condensing/Outdoor Unit: The condensing unit is located outside of the home and works to collect and remove heat from the home.
Condenser Coil: This is located in the outdoor condensing unit and is where the heat is removed from the refrigerant in the system.
Evaporator Coil: This is located inside the home and absorbs the heat out of the air via the refrigerant, then sending it to the condensing coil outside to be expelled from the system.
Heat Pump System: A system that is composed of an indoor air handler and the outdoor "Heat Pump" unit, it functions as a heater in the winter and a air conditioner in the summer.
SEER: Stands for Seasonal Energy Efficiency Ratio. This is A measure of an air conditioner's cooling efficiency. The higher the SEER, the more efficient the product. In California, the minimum seer rating you can purchase is 14 seer.
Two Stage Systems: Have ability to operate at full capacity when the demand is high or approximately half of their capacity when simply maintaining temperature in the home. These systems are good for increasing overall efficiency of system.