Glossary of Air Conditioner Terms by Guide4Home

Air conditioner: An appliance used for cooling, humidifying, dehumidifying or any other air treatment.

Air flow volume: The amount of air that is circulated through your home or room by the air conditioners. This is usually measured in cubic feet per minute or CFM. This is generally referred to as air circulation. Click on the central air conditioners link to read more about airflow in ductwork.

AFUE: Abbreviation for Annual Fuel Utilization Efficiency. This is a measurement of the efficiency of a gas furnace. The higher this rating is the more efficient the furnace will be.

Air handler: This is a device that moves and mixes air. They include fan blowers, coils, filters and expansion mechanisms. Generally, the air conditioner unit containing these components is referred to as the air handling unit and will be situated indoors. Click on the split systems link to learn more about air conditioner structure.

ARI: Abbreviation for the Air Conditioning and Refrigeration Institute

ASHRAE: Abbreviation for the American Society of Heating, Refrigeration and Air Conditioning Engineers

BTU: British thermal unit. This the measurement used to describe the cooling capacity, or amount of heat removed from the air, of the air conditioner. It is a measurement worked out according to the amount of cooling needed to lower the temperature of one pound of water by one Fahrenheit degree. One ton of cooling is the equivalent of 12,000 Btu’s/h. Go to air conditioners for sale to learn more about the cooling capacity in relation to cooling requirements.

Capacity: This refers to the amount of cooling an air conditioner is capable of producing. It is normally measured Btu/h (Btu’s per hour) or in tons.

Charge: Air conditioners do not consume refrigerant, instead it is reused in a continuous cycle. This cycle is contained within a sealed structure. To charge an air conditioner is to add more refrigerant to replace the old and involves recovering the old refrigerant first.

Compressor: This component is responsible for compressing the refrigerant and then pumping around the system. You can read more about this here.

Condensate: This occurs mainly in the evaporator coils when the refrigerant evaporates into a vapor after heat is absorbed from room air. Warm room air is circulated here in order to cool it and it is this change in the temperature that results in vapor condensing into a liquid. To learn more about how air conditioners work click here.

Condenser coil: Tubing made of either copper or aluminum situated in the condenser or outdoor unit. Hot refrigerant gas is pumped through these coils from the condenser; the heat from the gas is dispersed by circulating air over the coils. The heat transfers from refrigerant to air and is released outside. This heat dissipation converts the refrigerant from a gas into a liquid. Go to the ‘How air conditioners work’ page to learn more.

Condenser fan: There are two fans blades in every air conditioner. The condenser fan is for circulating the air over the condenser coils to dissipate the heat from the refrigerant. The other circulates the air over the evaporator coils and back into the room or building. Go to the ‘ Air conditioner parts ’ page to learn more about the different components involved in the functions of your cooling system.

Damper: This is a plate that can be opened or closed to control and balance the airflow throughout the air handler’s ductwork. This control is most obvious in systems with a ‘zoning’ option where cooling can be confined or regulated in individual rooms.

Click on the 'Ductless air conditioners' link to learn more about these systems.

Diffuser: This is a specialized grille with adjustable vents to direct the airflow from the air conditioner into the room. Some models come with a variety of adjustments some of which can distribute airflow in a particular pattern. An example would the ‘shower’ pattern of cool air.

Drain pan: Also known as the condensate pan, this is a pan positioned at the bottom of the air handling unit underneath the evaporator coils. As the name suggests, it collects the condensate that drips from the evaporator coils. This is then drained out through a drain pipe or, as is the case with some portable units, is removed and emptied.

Ductwork: This can basically be described as a large pipe that carries airflow throughout the building both to and from rooms. These can be used for both heating and cooling. Ductwork is commonly made of metal but flexible ductwork, known as mini-duct, is now also available.

EER: Abbreviation for Energy Efficiency Ratio. This is a measurement of the efficiency of the cooling unit. It is calculated by comparing the Btu’s to the watts of electricity consumed and the higher the efficiency rating the more efficient the unit. This benefits both environment and consumer as less energy is used which results in a lower operating costs.

Expansion valve: This device controls the temperature and pressure of the refrigerant preventing damage to the compressor.

Evaporator coil: Copper or aluminum tubing situated in the indoor or air handling unit. Liquid refrigerant from the condenser coils is pumped into these coils and evaporates into a vapor as it absorbs heat from warm room air. The air is circulated over the coils by the fan and, once relieved of its excess heat, is pumped back into the room. Click here to read more about other air conditioner parts.

Filter: Material that removes unwanted particles, such as dust and pollen, from the air that passes through it. Click filters to learn more about these.

Fuse: This is a small piece of metal found in all electrical circuits that is designed to melt when a surplus amount of electrical current passes through it. This is preventative measure taken to avoid damage to the other components of the system. They are commonly found in electrical plugs.

Heat exchanger: In air conditioners these are also known as the condenser and evaporator coils. It is where heat moves from a substance or surface with a higher temperature to a cooler temperature.

Heat pump: This is a compression system using refrigerant that can be used for both heating and cooling.

HVAC: Heating, Ventilating and Air Conditioning. This is an example of a system that would use a heat pump.

NEC: Abbreviation for National Energy Council or National Electric Code.

NEMA: Abbreviation for the National Electrical Manufacturing Association.

Package unit: A term to describe an air conditioner system where all the components are contained within one unit. Click on unit air conditioners to learn more.

Refrigerant: This is a liquid with an extremely low boiling point of minus 21.7°F. This gives it unique cooling qualities. Because it responds well to low pressure conditions and condenses easily it is easy to change the temperature of the substance which means it is easy to cool. When it is cooled it absorbs heat quickly and effectively. Click on the automotive AC link to learn more about the dangers of refrigerant.

Refrigerant charge: This is the amount of refrigerant required by a particular system.

SEER: Abbreviation for Seasonal Energy Efficiency Ratio. This is the measurement used to rate the efficiency for a cooling system that can also be used for heating (i.e. containing a heat pump. The higher the SEER, the more efficient the system.

Self-contained system: Similar to a package unit where all components are contained within on cabinet. Portable and window air conditioners are examples of such systems.

Split-system: This is an air conditioner that has been split into two units. The outdoor unit contains the condenser and compressor, the indoor unit contains the evaporator coil. Click here to read more on these.

Ton: Another unit used to measure the cooling capacity of an air conditioner. One ton of cooling is equal to 12,000 Btu’s/h.



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Home Care

Climate Control
Air Conditioners
Guide to Air Conditioners
Unit Air Conditioners
How Air Conditioners Work
Air Conditioner Installation
Glossary of Terms
Room Air Conditioners
Central Air Conditioners
Ductless Air Conditioners
Roof Top Air Conditioners
Split System Air Conditioners
Casement Air Conditioners
Window Air Conditioners
Portable Air Conditioner
Computer Room Air Conditioner
Armana Air Conditioners
Bryant Air Conditioners
Carrier Air Conditioners
Fedders Air Conditioners
Friedrich Air Conditioners
Goodman Air Conditioners
Rheem Air Conditioners
Trane Air Conditioners
York Air Conditioners
Parts and Maintenance
Air Conditioner Maintenance
Air Conditioner Service
Air Conditioner Parts
Air Conditioner Filters
Air conditioner Compressor
Buying Guide
Air Conditioner Rental


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