HVAC Terms & Definitions
Air conditioning:
A system that cools and dehumidifies the air inside a building or vehicle, providing comfort in hot weather. Air conditioning systems typically consist of an indoor unit (evaporator coil), an outdoor unit (compressor and condenser coil), and a means of circulating the cool air (ductwork or air handler).
Ductwork:
A system of pipes or ducts that distribute heated or cooled air throughout a building. Ductwork can be made of various materials, including metal, fiberglass, and flexible ducting, and is typically located in the attic, crawlspace, or basement of a building.
Refrigerant:
A substance used in air conditioning systems to transfer heat from the inside of a building to the outside. The most common refrigerants used in air conditioning systems are hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), and chlorofluorocarbons (CFCs).
Thermostat:
A device that controls the temperature of a building by turning the heating and cooling system on and off. Thermostats can be mechanical or digital, and can be programmed to maintain a certain temperature at specific times of the day.
Evaporator coil:
A component of an air conditioning system that removes heat from the air inside a building and transfers it to the refrigerant. The evaporator coil is typically located inside the air handler or furnace, and is usually made of copper or aluminum.
Condenser coil:
A component of an air conditioning system that removes heat from the refrigerant and transfers it to the outside air. The condenser coil is typically located outside the building, and is usually made of copper or aluminum.
Blower:
A component of an air conditioning or heating system that circulates air throughout the building. Blowers can be either electric or fan-driven, and can be located in the air handler or furnace.
Compressor:
A component of an air conditioning system that increases the pressure of the refrigerant, causing it to release heat outside the building. The compressor is typically located outside the building, and is usually powered by electricity.
Furnace:
A heating system that uses a fuel source (natural gas, propane, oil, or electricity) to generate heat, which is then distributed throughout the building. Furnaces typically include a heat exchanger, blower, and ductwork.
Heat pump:
A heating and cooling system that uses a refrigerant to transfer heat from one place to another. Heat pumps can be used for both heating and cooling, and are typically more energy-efficient than traditional heating and cooling systems.
Insulation:
Materials used to reduce heat loss or gain in a building, improving energy efficiency and comfort. Insulation can be made of various materials, including fiberglass, cellulose, and spray foam, and is typically located in the walls, attic, and floors of a building.
Filter:
A device that removes impurities from the air, improving indoor air quality. Filters can be made of various materials, including paper, fiberglass, and HEPA, and are typically located in the air handler or furnace.
Air handler:
A component of an air conditioning or heating system that circulates air throughout the building. Air handlers can be located in the attic, crawlspace, or basement of a building, and typically include a blower, evaporator coil, and filter.
Zone control:
A system that allows for different temperature zones in a building to be controlled independently, improving energy efficiency and comfort. Zone control systems typically include multiple thermostats and dampers that control the flow of air to each zone.
Damper:
A device that regulates the flow of air in a duct system. Dampers can be manual or automatic, and are typically used in zone control systems.
Boiler:
A heating system that uses hot water or steam to generate heat, which is then distributed throughout the building. Boilers can be fueled by natural gas, propane, oil, or electricity.
Radiant heating:
A heating system that uses hot water or electric coils to generate heat, which is then radiated into the room. Radiant heating systems can be located in the floor, walls, or ceiling.
Chillers:
A type of air conditioning system that cools water, which is then used to cool the air in the building. Chillers can be air-cooled or water-cooled, and are typically used in large commercial or industrial buildings.
HVAC:
An acronym for heating, ventilation, and air conditioning. HVAC refers to the components and systems used to control the temperature, humidity, and air quality in a building.
Load calculation:
The process of determining the heating and cooling requirements of a building, taking into account factors such as square footage, insulation, and orientation. Load calculations are used to size HVAC systems properly and improve energy efficiency.
SEER:
An acronym for Seasonal Energy Efficiency Ratio, a measure of the efficiency of air conditioning systems. The higher the SEER rating, the more energy-efficient the system.
AFUE:
An acronym for Annual Fuel Utilization Efficiency, a measure of the efficiency of heating systems. The higher the AFUE rating, the more energy-efficient the system.
BTU:
An acronym for British Thermal Unit, a unit of energy used to measure the heating or cooling capacity of HVAC systems.
Ton:
A unit of measurement used in air conditioning systems to describe the cooling capacity of a system. One ton is equivalent to 12,000 BTUs per hour.
Ductless mini-split:
A type of air conditioning system that does not use ductwork. Ductless mini-splits consist of an outdoor unit and multiple indoor units, and are typically used in older buildings or in room additions.
Hybrid system:
A type of HVAC system that combines two or more heating and cooling technologies, such as a heat pump and a furnace. Hybrid systems are typically more energy-efficient than single-technology systems.
Geothermal heat pump:
A type of heat pump that uses the constant temperature of the earth to generate heat in the winter and remove heat in the summer. Geothermal heat pumps are typically more energy-efficient than traditional heat pumps.
Indoor air quality:
The quality of the air inside a building, which can be affected by factors such as air exchange rate, humidity, and pollutants. Indoor air quality is important for both health and comfort.
Ventilation:
The process of exchanging indoor air with outdoor air to improve indoor air quality and reduce moisture buildup. Ventilation can be achieved through natural means (open windows) or mechanical means (exhaust fans).
Duct cleaning:
The process of removing contaminants from the ductwork of an HVAC system, improving indoor air quality