Also referred to as (Line-set). Set of two copper lines connecting the outdoor unit and the indoor unit.

Also referred to as (Floor Grille) or (Ceiling Grille). Combination grille and damper assembly covering an air opening or end of an air duct.

The ratio of the amount of vapor contained in the air to the greatest amount the air could hold at that temperature. Normally expressed as a percentage.

Also referred to as (Return). The path of air as it goes to the air-handler or furnace so it can be cooled or heated. The Return side should be "balanced" with the supply side to achieve optimum airflow and comfort. Sometimes described as "return", or "return air". Contrast with "supply side".

A device in a heat pump that reverses the flow of refrigerant as the system is switched from cooling to heating.

A compressor that uses two spiral-shaped scrolls to pump or compress liquids and gases. One scroll is fixed, while the other moves in an eccentric way without rotating. This traps and compresses pockets of fluid or gas between the scrolls. These are also called a "scroll pump" or a "scroll vacuum pump",

Seasonal Energy Efficiency Ratio; a measure of cooling efficiency for air conditioners and heat pumps. The higher the SEER, the more energy efficient the unit.

The most common type of air conditioning and heating systems found in homes. It is a central system with two or more major components located apart from each other. The condensing unit is located outside the structure, and the air handling unit is located inside. Refrigerant lines and electrical wiring run between the two. The components of split systems must be matched for optimum efficiency. Contrast with "package unit".

A refrigerant metering device that maintains a constant evaporator temperature by monitoring suction vapor superheat; also called a thermal expansion valve.

The factor representing resistance to heat flow of various building materials.

A pressure below atmospheric pressure. A perfect vacuum is 30 inches Mercury (periodic symbol "Hg").

The unit of electrical power equal to the flow of one amp at a potential difference of one volt.

York International Corporation sells central air conditioner units and furnaces for residential, light commercial and other HVAC units for industrial. York International Corp. is one of the oldest companies and it's first connection with refrigeration equipment was in 1903. York International also markets their HVAC units under the brand names Coleman, Luxaire, and York.

A method of dividing a home into different comfort zones so each zone can be independently controlled depending on use and need; an air conditioning system capable of maintaining varying conditions for various rooms or zones.