Common Terms and Phrases Used by the Furnace Industry

The HVAC industry (heating, ventilation, and air conditioning), like any specialised industry, has a vocabulary that you may not be familiar with unless you have experience with HVAC. Learning common phrases and acronyms will help you properly communicate your needs to an HVAC technician as well as better understand the literature that came with your air conditioner, humidifier, and furnace.

Note that the list below is appended to focus on terms that you may encounter. For a more complete list please visit: http://en.wikipedia.org/wiki/Glossary_of_HVAC_terms.

Air conditioner – The appliance/mechanism that dehumidifies and extract

Blower motor – The motor that drives the fan blades that circulate air over the heat exchanger and throughout your home.

British Thermal Unit (BTU) – One BTU is the energy required to raise one pound of water one degree Fahrenheit. It is commonly used to express the rate of cooling/dehumidifying/heating for HVAC systems (ie – a portable air conditioner is rated at 5,000 BTU’s).

Cold air return – A large vent, typically mounted where the floor meets the baseboard. The cold air return acts as the intake for a furnace system, enabling the furnace to draw ambient air from inside the home down to be heated and then recirculated.

Condenser – A component inside an air conditioner that removes heat from the system. A condenser can transfer heat to air or an intermediate fluid.

Duct – A network of ducts direct air from the furnace throughout the home.

Furnace – The most visible part of your home’s HVAC system. A furnace heats air by combustion (in natural gas or propane furnaces) or via heat coils (electric furnace).

Heat Exchanger – Part metal chamber, part passageway, the heat exchanger extracts heat from the hot air generated by the burners in your furnace. Air is then forced over the heat exchanger by the blower motor (or fan), and the resulting warmed air is then circulated throughout the home.Many high efficiency furnaces have two heat exchanges to maximize the amount of heat extracted from a given amount of fuel.

Pilot Light – On many natural gas furnaces a pilot light is used to facilitate ignition. Pilot lights should be checked regularly to verify that they are working properly.

Thermostat – A device that is typically mounted in a centralized location within a home that enables you to regulate the indoor air temperature. There are many different types of thermostats that will facilitate different functions, but all accomplish the same general purpose of sending a signal to the furnace when temperatures have dropped below the specified limit.