HVAC Glossary



The branded name from American Standard Heating and Air Conditioning’s whole-home air filtration that is designed to remove up to 99 percent of airborne allergens in the home.


Annual Fuel Utilization Efficiency. AFUE is a rating system that addresses how efficiently a gas furnace turns fuel into energy.

Air Cleaner

A device that removes allergens and particles from the air inside a living space.

Air Conditioner

A network of components designed to control the air temperature and airflow inside a living space.


Distribution of or the movement of air throughout a living space.



The portion of the air conditioner that moves hot or cold air throughout the ductwork.


Stands for British thermal unit and is a measurement of heat energy. One Btu is the amount of heat needed to raise one pound of water by one degree in Fahrenheit.



A piece of equipment’s ability to output cooling or heating. Usually measured in Btu.

Carbon Monoxide

A gas that is odorless, tasteless, poisonous and highly flammable. It is produced when carbon burns with insufficient air.


The main component of an air conditioner. It pumps refrigerant and maintains adequate pressure for sufficient flow. By doing so, it can meet the temperature requirements you set on your thermostat.


Cubic Feet per Minute. A measurement that addresses the amount of passing cubic feet of air per minute. The higher the number, the more air your conditioner pumps through the ductwork.

Condenser Coil

The portion of the air conditioner that removes refrigerant from inside the home to the outdoors.



A movable plate that opens and closes to control airflow inside the ductwork.


The Department of Energy. A federally run program responsible for addressing the energy efficiency standards.


A closed chamber that conducts the airflow throughout the inside of a home.


When air enters at the top/bottom of a unit and is removed vertically out the other side.



Energy Efficiency Ratio. The standard that measures the energy efficiency of an air conditioner. The higher the number, the more efficient it is.


Used to describe the amount of energy needed to accomplish a cycle. The higher the number, the more efficient your system is.

Energy Star®

A program developed by the EPA in an effort to reduce U.S. energy consumption. Air conditioners purchased with an Energy Star® will save up to 15 percent more energy than counterparts.


Environmental Protection Agency. It oversees and enforces federal environmental regulations.

Evaporator Coil

Located inside the air handler of your air conditioner. Its role is to absorb heat from the air produced.


Fan Coil

A system that uses a cooling or heating coil in addition to a fan to move air.

Fresh Air Intake

The portion of the unit that is open to allow outdoor air into the system.


The component of the HVAC system that adds heat.


Heat Pump

A system that is used to cool your home in the summer and heat it in the winter.

Home Automation

Remote access to controls to set things inside your home such as the HVAC system.


Heating Seasonal Performance Factor. A measurement relating to the efficiency of the heat pump. The higher the number, the more efficient.


An acronym for Heating, Ventilation, and Air Conditioning.


The amount of moisture found inside the air.


Indoor/Outdoor System

A system that has components found both inside and outside the home.

Indoor Coil

Attached to your air handler that draws out moisture and heat as air flows across it. The result is cool and comfortable air.



Leadership in Energy and Environmental Design which is a Green Building Rating System™.

Load Calculation

A measurement articulating the amount of heat loss or gain. It is used to determine the size of the HVAC system needed to work for your home.


Matched System

When your heating or cooling system’s components match in capacity and efficiency. When all things match, your HVAC performs at its best.

Modulating Heating

Method for heating your home that is more fuel efficient and provides ideal comfort as it adjusts to temperature changes.



North American Technician Excellence. A certification program for technicians recognized throughout the industry.


Outdoor Coil

A coil that changes refrigerant from vapor to liquid and is located in the outdoor unit.


Refers to air contaminants relating to gas.


Packaged System

When your air conditioner and its components are located in one unit.


Substances in the air that measure less than 100 microns in diameter.

Payback Analysis

Determines the value of your system by comparing the number of months required before monthly energy cost savings that make up for the purchase price.



The substance needed to produce a cooling effect in an air conditioner.


A grille assembly covering the opening of the air duct.

Return Air

The air being drawn into the HVAC after circulating a room.



A rating that describes the efficiency of an air conditioning equipment. It specifically refers to the efficiency throughout a cooling season. The higher the rating, the more efficient it is.

Split System

Refers to the combination of a compressor and condensing unit installed inside a home and an air handler outside the home.


The umbrella term that refers to all the components of an HVAC unit.



A device found on the inside of the home that is used to control the temperature of the heating and cooling system.


A unit of measurement determining the cooling capacity of an air conditioner.

Two-Stage Heating/Cooling

A type of system that operates with low, energy-saving speed.



When air enters the system and is discharged vertically through the top.


Variable Speed Motor

Adjusts the airflow automatically to ensure maximum comfort.


The part of the system that changes stale air and recirculates it with fresh air.



A set of controls that allows you to independently heat or cool different areas of a room or home. Programmable thermostats control operating times with separate controls for opening and closing vents/ducts in different “zones.”

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