Glossary of Terms
Heating Venting and Air Conditioning(HVAC)
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Term : Definition
Air Conditioner
Device used to lower air temperature. Cooling typically happens through heat transfer with refrigerant cycle.
Air Handler/Electric Furnace
Metal box containing blower, heating elements and system controls. Normally attached to duct work which distributes conditioned air throughout a building.
BTU (British Thermal Unit)
Measurement of energy(heat) required to raise a temperature. In the U.S., BTU is used for the rating power of HVAC systems.
Coil
Equipment that performs a heat transfer as air blows over the unit.
Damper
An adjustable blade inside duct to control air flow.
Dehumidifier
Equipment used to extract and remove humidity from air. Drops air temperature to turn water vapor to liquid. Dehumidification naturally occurs during air conditioning.
Duct
Method of transferring air from one area to another. Used in heating, cooling or ventilation.
Fresh Air
Outside air that is introduced inside a building to help cycle new air.
Filter
Removable device that is placed in the air intake portion of the system. It provides protection for the motor, fan, and heating coil by removing impurities. It also contributes to the Indoor Air Quality of a building.
Furnace
Similar to an air handler. Metal box containing burners, heat exchanger, blower and controls. Fuel can be Natural Gas, Propane, or Oil.
Grille
A covering over a duct opening that has slots in it to deliver(supply) or recover(return) air. The grille directs air and prevents entry of larger objects.
Heat Exchanger
Portion of a combustible furnace(Gas or Oil) that transfers heat to be expelled by the unit.
Heat Pump
Outdoor unit that has a compressor to cycle hot and cold refrigerant. Transfers heat from one area to a cooler area.
HSPF
Heating Seasonal Performance Factor. Used to measure the heating efficiency of air source heat pumps. Higher the number, the more efficient the unit.
Indoor Air Quality (IAQ)
Term used to refer to air quality inside a building or structure. It commonly relates to the health and comforts of the occupants inside the building.
Packaged Unit
An air handler specially designed for outdoor installation with ducts that run into a structure. They normally contain both the heating and cooling portions of the system.
Plenum
Metal boxes attached to an indoor system. Airflow is then distributed from the plenum into ductwork.
Refrigerant
A mixture that changes from a liquid to gas to transfer heat from one place to another.
Seer
Seasonal Energy Efficiency Ratio. Cooling performance rating system for Air Conditioners and Heat Pumps. Higher the rating, the more efficient the system.
Split System
Combination of an outdoor unit and an indoor unit. Most common type of system.
System
General term referring to a unit that performs a specific HVAC function.
Thermostat
Monitor and regulator of a heating and cooling system. Used to set a desired temperature.
Thermostatic Expansion Valve(TXV or TEV)
A piece of equipment that meters the flow of liquid refrigerant entering an evaporator while measuring the vapor refrigerant leaving the evaporator.
Two-Stage
System designed to operate on a high and low setting during different demands placed upon the system.
Zoning
Created section of a building or space that are controlled independently of each other. Different sections then can have own desired temperature using independent thermostats.
