Accumeter: The metering (flow control) device inside a Carrier centrifugal chiller. Its unique design always feeds the cooler with liquid refrigerant, which has a much greater cooling capability than a gaseous refrigerant.

Accurator: A piston type metering device that feeds the proper amount of liquid refrigerant into the evaporator.

AFUE: Annual Fuel Utilization Efficiency. The AFUE percentage tells you how much energy is being converted to heat. The higher the number the greater the efficiency.

Air Conditioner: Assembly of equipment for the simultaneous control of air temperature, relative humidity, purity, and motion.

Air-Cooled System: A type of air conditioning system that uses freon as a refrigerant and air as a condensing medium. Typically, the air-cooled condenser is located outside and refrigerant lines are piped to it from the indoor unit.

Air Handler: The portion of your heating and cooling system that forces air through your home’s ductwork.

BTU: British Thermal Units. The amount of heat it takes to raise one pound of water one degree Fahrenheit. The higher the BTU rating, the larger the heating capacity of the furnace or air conditioner.

Capacity: The ability of a heating or cooling system to heat or cool a given amount of space. Heating is usually expressed in BTUs, cooling is expressed in tons.

Compressor: The motor/pump that drives the air conditioning unit. It is responsible for pumping refrigerant throughout the system.

Condenser Coil: Part of the outdoor portion of a heating or cooling system, that releases or collects heat from the outside air.

Damper: A valve or movable plate used in ductwork that opens and closes to control airflow. They are used to direct air to specific areas of the home.

Downflow: A type of furnace that takes cool air from the top and blows warm air to the bottom.

Ductwork: Hollow metal pipes used to transfer air throughout your house.

Electronic Air Cleaner: An electronic device that filters out particles and contaminants in indoor air.

Evaporator Coil: Part of the heating or cooling system located indoors, that cools and dehumidifies the air by converting liquid refrigerant into gas.

Heat Exchanger: A device for the transfer of heat energy from the source to the conveying medium.

Heat Pump: An air conditioner that contains a valve that allows it to alternate between heating and cooling.

Horizontal Furnace: A furnace that lies on its side, pulling in return air from one side and expelling warm air from the other.

HSPF – Heating Seasonal Performance Factor: Heating Seasonal Performance Factor. Measures the heating efficiency of a heat pump. The higher the number the more efficient the heat pump heats your home.

Humidifier: A piece of equipment that adds moisture to the air as it comes out of the furnace.

HVAC: Heating, Ventilation, and Air Conditioning.

Refrigerant: A substance that produces a refrigerating effect while expanding or vaporizing.

SEER: A rating that denotes the efficiency of air conditioning equipment. It is the amount of cooling your equipment delivers for every dollar spent on electricity. It is the ratio of cooling delivered by a system, measured in BTUs, to the dollar cost of the electricity to run the system, as measured in watt-hours. This ratio is determined using specified federal test procedures. The higher the SEER, the more efficient the unit. The more efficient the unit, the lower the operating cost.     Single Package

A year-round heating and air conditioning system that has all of the components completely encased in one unit outside the home.

Split System: A central air conditioner consisting of two or more major components. The system usually consists of a compressor-containing unit and condenser, installed outside the building and a non-compressor – containing air handling unit installed within the building. This is the most common type of system installed in a home.

Thermostat: A temperature control device, typically found on a wall inside that consists of a series of sensors and relays that monitor and control the functions of a heating and cooling system.

Upflow: A type of air conditioning system that discharges air into the conditioned space via a top-mounted discharge plenum or through an overhead duct system.

Ventilator: A ventilator captures heating or cooling energy from stale indoor air and transfers it to fresh incoming air.

Zoning: The practice of providing independent heating and/or cooling to different areas in a structure. Zoning typically utilizes a system controller, zoning dampers controlled by a thermostat in each zone, and a bypass damper to regulate static pressure in the supply duct.