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HVAC Glossary



Annualized Fuel Utilization Efficiency is a measure of your furnace's heating efficiency. The higher the AFUE percentage, the more efficient the furnace. The minimum percentage established by the DOE for furnaces is 78%.


Air Conditioning, Heating and Refrigeration Institute. An industry trade association that develops standards for measuring and certifying product performance.

Air Conditioning

Air conditioning refers to the cooling and dehumidification of indoor air for thermal comfort.

Air Handler/Coil Blower

The indoor part of an air conditioner or heat pump that moves cooled or heated air throughout the ductwork of your home. An air handler is usually a furnace or a blower coil.


A British thermal unit is a unit of heat energy. One BTU is the amount of heat required to raise one pound of water by one degree Fahrenheit. The higher the Btu rating, the greater the heating capacity of the system.


British thermal units per hour.


The Combined Annual Efficiency is a measure of the amount of heat produced for every dollar of fuel consumed for both home and water heating.

Carbon Monoxide

An odorless, colorless, tasteless, poisonous and flammable gas that is produced when carbon burns with insufficient air.

Central System

System in which air is treated at a central location and distributed to and from rooms by one or more fans and a series of ducts.


Stands for Cubic Feet per Minute. This measurement indicates how many cubic feet of air pass by a stationary point in one minute. The higher the number, the more air is being moved through the ductwork by the system.


The part of the outdoor air conditioner or heat pump that compresses and pumps refrigerant to meet household cooling requirements.

Condenser Coil

The outdoor portion of an air conditioner or heat pump that either releases or collects heat, depending on the time of the year.


A decibel is a unit used to measure the relative intensity of sound.

Dual Fuel

A comfort system that pairs an electric heat pump with a gas furnace, providing an energy-efficient alternative to the conventional furnace/air conditioner combination.


EnerGuide is a Government of Canada initiative that rates the energy consumption and efficiency of household appliances, heating equipment, cooling equipment, ventilating equipment, new houses and personal vehicles. The EnerGuide label is used to make informed buying decisions by comparing the energy performance of different products.


The international Energy Star symbol identifies major electrical appliances that meet or exceed technical specifications designed to ensure that they are among the most energy efficient in their class, without compromising performance. The designation Energy Star Most Efficient recognizes and the most efficient products among those that qualify.

Evaporator Coil

The part of the air conditioner or heat pump that is located inside the air handler or attached to the furnace. Its primary function is to absorb the heat from the air in your house.


Geothermal systems use the solar energy that is stored year-round just beneath the earth's surface. This energy is free, unlimited, 100% renewable. A geothermal system is a proven cost-effective way of heating, cooling and providing hot water in a home while emitting absolutely no carbon dioxide, carbon monoxide or other harmful greenhouse gases.

Heat Pump

A heat pump is an HVAC unit that heats or cools by moving heat. During the winter, a heat pump draws heat from outdoor air and circulates it through your home's air ducts. In the summer, it reverses the process and removes heat from your house and releases it outdoors.


HSPF stands for Heating Seasonal Performance Factor and measures heat pump efficiency. The minimum set by the Department of Energy is 6.8 HSPF and for Energy Star, 8 HSPF. The higher the HSPF, the greater the energy economy.