Terminology
& Glossary
Your comprehensive guide to understanding HVAC terminology and enhancing your knowledge of home comfort systems
Welcome to our HVAC Glossary, your go-to resource for demystifying the world of heating, ventilation, and air conditioning. In the realm of HVAC, understanding the terminology is key to making informed decisions about your home’s comfort and energy efficiency.
Whether you’re a seasoned homeowner looking to brush up on your knowledge or a newcomer seeking clarity on common industry jargon, our glossary is designed to provide clear, concise explanations of HVAC terms. Dive in, expand your HVAC vocabulary, and gain the confidence you need to make the best choices for your home’s heating and cooling needs.
Absolute Pressure: Gauge pressure plus atmospheric pressure (14.7 lb.per sq.in.) equals absolute pressure.
Absolute Temperature: Temperature measured from absolute zero.
Absolute Zero Temperature: Temperature at which all molecular motion ceases(-460 F. and -273 C.
Absorbent: Substance with the ability to take up or absorb another substance.
Absorption Refrigerator: Refrigerator which creates low temperature by using the cooling effect formed when a refrigerant is absorbed by chemical substance.
ACCA: A leading HVAC/R Association – http://www.acca.org/
Accessible Hermetic: Assembly of a motor and compressor inside a single bolted housing unit.
Accumulator: A storage tank that receives liquid refrigerant from the evaporator and prevents it from flowing into the suction line before vaporizing.
ACH (Air Changes Per Hour): The number of times that air in a house is completely replaced with outdoor air in one hour.
AFUE (Annual Fuel Utilization Efficiency): A rating that measures the efficiency of a furnace or boiler in converting fuel into heat over an entire heating season.
Air Filter: A device used to remove particles and contaminants from the air, improving indoor air quality.
Airflow: The movement of air within an HVAC system or space.
Air Handler: A component of an HVAC system that circulates air and often includes a blower, filter, and coil.
Airflow Rate: The volume of air that flows through an HVAC system or ductwork in a given time period.
Ambient Temperature: The temperature of the surrounding environment.
ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers): An organization that sets standards for HVAC system design and performance.
Auxiliary Heat: Supplementary heating used in heat pump systems when the primary heat source is insufficient to meet heating demands.
Baffle: A device used to control the flow of air or gas within a duct or ventilation system.
Balancing Damper: A damper used to regulate and balance airflow within ductwork.
BTU (British Thermal Unit): A unit of energy used to measure heating and cooling capacity.
BTUH (British Thermal Units per Hour): A unit of measurement used to quantify the heat output or cooling capacity of a system over an hour.
CFC (Chlorofluorocarbon): A type of refrigerant known for its harmful impact on the ozone layer, now mostly phased out in HVAC systems.
Charge: The amount of refrigerant within an HVAC system.
Coefficient of Performance (COP): A measure of the efficiency of a heat pump or refrigeration cycle.
Compressor: A component of an HVAC system responsible for compressing refrigerant gas, which allows it to release and absorb heat.
Condensation: The process of changing a gas or vapor into a liquid.
Condenser Coil: A component of an air conditioning system located outdoors, where refrigerant releases heat to the outside air.
Condensing Unit: The outdoor component of a split-system air conditioner or heat pump.
Coolant: A substance, often refrigerant, used in an HVAC system to transfer heat.
COP (Coefficient of Performance): A measure of the efficiency of a heat pump or refrigeration cycle.
Dampers: Adjustable plates or valves used to control airflow within ducts.
Dehumidification: The process of removing moisture from indoor air to improve comfort and air quality.
Desiccant: A substance used to absorb moisture from the air.
Dew Point: The temperature at which air becomes saturated with moisture and dew forms.
Diffuser: A device that disperses conditioned air into a room.
Ductless Mini-Split System: An HVAC system that doesn’t require ductwork and consists of an outdoor unit and indoor air-handling units.
Dual Fuel System: A system that combines a heat pump and a furnace for energy-efficient heating and cooling.
Duct: A tube or conduit used to convey air within an HVAC system.
EER (Energy Efficiency Ratio): A measure of how efficiently an HVAC system cools under specific conditions.
Efficiency: The ratio of useful output to total input, often used to measure the performance of HVAC systems.
Electronic Air Cleaner: A device that uses an electrical charge to remove particles from the air.
Evaporator Coil: A component of an air conditioner or heat pump where refrigerant evaporates and absorbs heat from indoor air.
Expansion Valve: A device that regulates the flow of refrigerant into the evaporator coil.
Fan Coil Unit (FCU): A device that contains a fan and a coil used for heating or cooling.
Filter: A device used to remove airborne particles from the air.
Furnace: A heating system that burns fuel or uses electricity to generate heat.
Heat Exchanger: A device that transfers heat from one fluid to another without them coming into direct contact.
Heat Pump: An HVAC system that can both heat and cool by transferring heat between indoor and outdoor environments.
Humidifier: An appliance or component of an HVAC system that adds moisture to indoor air.
HVAC: An abbreviation for Heating, Ventilation, and Air Conditioning.
IAQ (Indoor Air Quality): The quality of air within a building, including factors like temperature, humidity, and air cleanliness.
Inverter: A technology used in some HVAC systems to vary compressor speed for greater energy efficiency.
Load Calculation: A method used to determine the heating and cooling requirements of a building.
MERV (Minimum Efficiency Reporting Value): A rating that measures the efficiency of air filters in capturing airborne particles.
Multi-Zone System: An HVAC system that can independently control temperature in different areas or zones.
Natural Gas: A common fuel source for heating in HVAC systems.
Outdoor Unit: The part of an HVAC system located outside the building, often containing the compressor and condenser coil.
Package Unit: An HVAC system where all components are contained in a single unit installed outdoors.
Pilot Light: A small flame used to ignite the main burners in some gas heating systems.
Plenum: An enclosed space in which air is heated, cooled, or distributed.
Programmable Thermostat: A thermostat that allows users to set temperature schedules for different times of the day.
Psychrometrics: The study of the physical and thermodynamic properties of air-water mixtures.
R-Value: A measure of a material’s resistance to heat flow, often used to describe insulation effectiveness.
Refrigerant: A chemical substance used in HVAC systems to transfer heat between the indoor and outdoor units.
Registers: Grilles or vents used to control the flow of heated or cooled air into a room.
Return Air: Air that is drawn back into the HVAC system for conditioning.
Scroll Compressor: A type of compressor commonly used in HVAC systems for its efficiency.
SEER (Seasonal Energy Efficiency Ratio): A rating that measures the energy efficiency of air conditioners and heat pumps.
Single-Stage: An HVAC system or component that operates at one fixed level of heating or cooling capacity.
Split System: An HVAC system with indoor and outdoor components.
Supply Air: The conditioned air that is delivered into a space.
Thermostat: A device that controls the temperature in a building by activating the heating or cooling system as needed.
Ton: A unit of cooling capacity, equal to 12,000 BTUs per hour.
Two-Stage: An HVAC system or component that can operate at two different levels of heating or cooling capacity.
U-Factor: A measure of the rate of heat transfer through a building material or assembly.
UV-C Light: Ultraviolet (UV) light with a wavelength that can help kill or inactivate certain pathogens and microorganisms in the air.
Variable Air Volume (VAV): A system that adjusts the volume of conditioned air delivered to different zones or spaces based on demand.
Variable-Speed: A feature in HVAC systems where components such as fans or compressors can operate at varying speeds for improved efficiency and comfort.
Ventilation: The process of supplying outdoor air to indoor spaces and removing indoor air to maintain air quality and freshness.
Warm Air Furnace: A type of furnace that heats air and distributes it through ductwork.
Weatherization: The process of making a building more energy-efficient and resistant to outdoor weather conditions.
Zone Control: A system that divides a building into separate climate control zones, allowing for customized temperature settings in different areas.
Zoning: A method of controlling the temperature in different areas or zones of a building independently.
Absolute Pressure: Gauge pressure plus atmospheric pressure (14.7 lb.per sq.in.) equals absolute pressure.
Absolute Temperature: Temperature measured from absolute zero.
Absolute Zero Temperature: Temperature at which all molecular motion ceases(-460 F. and -273 C.
Absorbent: Substance with the ability to take up or absorb another substance.
Absorption Refrigerator: Refrigerator which creates low temperature by using the cooling effect formed when a refrigerant is absorbed by chemical substance.
ACCA: A leading HVAC/R Association – http://www.acca.org/
Accessible Hermetic: Assembly of a motor and compressor inside a single bolted housing unit.
Accumulator: A storage tank that receives liquid refrigerant from the evaporator and prevents it from flowing into the suction line before vaporizing.
ACH (Air Changes Per Hour): The number of times that air in a house is completely replaced with outdoor air in one hour.
AFUE (Annual Fuel Utilization Efficiency): A rating that measures the efficiency of a furnace or boiler in converting fuel into heat over an entire heating season.
Air Filter: A device used to remove particles and contaminants from the air, improving indoor air quality.
Airflow: The movement of air within an HVAC system or space.
Air Handler: A component of an HVAC system that circulates air and often includes a blower, filter, and coil.
Airflow Rate: The volume of air that flows through an HVAC system or ductwork in a given time period.
Ambient Temperature: The temperature of the surrounding environment.
ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers): An organization that sets standards for HVAC system design and performance.
Auxiliary Heat: Supplementary heating used in heat pump systems when the primary heat source is insufficient to meet heating demands.
Baffle: A device used to control the flow of air or gas within a duct or ventilation system.
Balancing Damper: A damper used to regulate and balance airflow within ductwork.
BTU (British Thermal Unit): A unit of energy used to measure heating and cooling capacity.
BTUH (British Thermal Units per Hour): A unit of measurement used to quantify the heat output or cooling capacity of a system over an hour.
CFC (Chlorofluorocarbon): A type of refrigerant known for its harmful impact on the ozone layer, now mostly phased out in HVAC systems.
Charge: The amount of refrigerant within an HVAC system.
Coefficient of Performance (COP): A measure of the efficiency of a heat pump or refrigeration cycle.
Compressor: A component of an HVAC system responsible for compressing refrigerant gas, which allows it to release and absorb heat.
Condensation: The process of changing a gas or vapor into a liquid.
Condenser Coil: A component of an air conditioning system located outdoors, where refrigerant releases heat to the outside air.
Condensing Unit: The outdoor component of a split-system air conditioner or heat pump.
Coolant: A substance, often refrigerant, used in an HVAC system to transfer heat.
COP (Coefficient of Performance): A measure of the efficiency of a heat pump or refrigeration cycle.
Dampers: Adjustable plates or valves used to control airflow within ducts.
Dehumidification: The process of removing moisture from indoor air to improve comfort and air quality.
Desiccant: A substance used to absorb moisture from the air.
Dew Point: The temperature at which air becomes saturated with moisture and dew forms.
Diffuser: A device that disperses conditioned air into a room.
Ductless Mini-Split System: An HVAC system that doesn’t require ductwork and consists of an outdoor unit and indoor air-handling units.
Dual Fuel System: A system that combines a heat pump and a furnace for energy-efficient heating and cooling.
Duct: A tube or conduit used to convey air within an HVAC system.
EER (Energy Efficiency Ratio): A measure of how efficiently an HVAC system cools under specific conditions.
Efficiency: The ratio of useful output to total input, often used to measure the performance of HVAC systems.
Electronic Air Cleaner: A device that uses an electrical charge to remove particles from the air.
Evaporator Coil: A component of an air conditioner or heat pump where refrigerant evaporates and absorbs heat from indoor air.
Expansion Valve: A device that regulates the flow of refrigerant into the evaporator coil.
Fan Coil Unit (FCU): A device that contains a fan and a coil used for heating or cooling.
Filter: A device used to remove airborne particles from the air.
Furnace: A heating system that burns fuel or uses electricity to generate heat.
Heat Exchanger: A device that transfers heat from one fluid to another without them coming into direct contact.
Heat Pump: An HVAC system that can both heat and cool by transferring heat between indoor and outdoor environments.
Humidifier: An appliance or component of an HVAC system that adds moisture to indoor air.
HVAC: An abbreviation for Heating, Ventilation, and Air Conditioning.
IAQ (Indoor Air Quality): The quality of air within a building, including factors like temperature, humidity, and air cleanliness.
Inverter: A technology used in some HVAC systems to vary compressor speed for greater energy efficiency.
Load Calculation: A method used to determine the heating and cooling requirements of a building.
MERV (Minimum Efficiency Reporting Value): A rating that measures the efficiency of air filters in capturing airborne particles.
Multi-Zone System: An HVAC system that can independently control temperature in different areas or zones.
Natural Gas: A common fuel source for heating in HVAC systems.
Outdoor Unit: The part of an HVAC system located outside the building, often containing the compressor and condenser coil.
Package Unit: An HVAC system where all components are contained in a single unit installed outdoors.
Pilot Light: A small flame used to ignite the main burners in some gas heating systems.
Plenum: An enclosed space in which air is heated, cooled, or distributed.
Programmable Thermostat: A thermostat that allows users to set temperature schedules for different times of the day.
Psychrometrics: The study of the physical and thermodynamic properties of air-water mixtures.
R-Value: A measure of a material’s resistance to heat flow, often used to describe insulation effectiveness.
Refrigerant: A chemical substance used in HVAC systems to transfer heat between the indoor and outdoor units.
Registers: Grilles or vents used to control the flow of heated or cooled air into a room.
Return Air: Air that is drawn back into the HVAC system for conditioning.
Scroll Compressor: A type of compressor commonly used in HVAC systems for its efficiency.
SEER (Seasonal Energy Efficiency Ratio): A rating that measures the energy efficiency of air conditioners and heat pumps.
Single-Stage: An HVAC system or component that operates at one fixed level of heating or cooling capacity.
Split System: An HVAC system with indoor and outdoor components.
Supply Air: The conditioned air that is delivered into a space.
Thermostat: A device that controls the temperature in a building by activating the heating or cooling system as needed.
Ton: A unit of cooling capacity, equal to 12,000 BTUs per hour.
Two-Stage: An HVAC system or component that can operate at two different levels of heating or cooling capacity.
U-Factor: A measure of the rate of heat transfer through a building material or assembly.
UV-C Light: Ultraviolet (UV) light with a wavelength that can help kill or inactivate certain pathogens and microorganisms in the air.
Variable Air Volume (VAV): A system that adjusts the volume of conditioned air delivered to different zones or spaces based on demand.
Variable-Speed: A feature in HVAC systems where components such as fans or compressors can operate at varying speeds for improved efficiency and comfort.
Ventilation: The process of supplying outdoor air to indoor spaces and removing indoor air to maintain air quality and freshness.
Warm Air Furnace: A type of furnace that heats air and distributes it through ductwork.
Weatherization: The process of making a building more energy-efficient and resistant to outdoor weather conditions.
Zone Control: A system that divides a building into separate climate control zones, allowing for customized temperature settings in different areas.
Zoning: A method of controlling the temperature in different areas or zones of a building independently.
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Peoria, AZ 85345
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Phone: 602-242-2353
Email: wahlaircond@air.com
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