The HVAC industry can be a maze of unfamiliar acronyms and industry terms. This dictionary will help you navigate the most common terms you'll come across during your buying decision.
- AC (Alternating Current)
- A type of current where the polarity is perpetually reversing, causing the directional flow in a circuit to reverse at regular intervals.
- Air Conditioning Contractors of America
- Relating to sound, the science of sound, or a sense of hearing.
- Annual Fuel Utilization Efficiency: A measurement used to rate furnace efficiencies by dividing the ratio of heat output by heat input
- American Gas Association, Inc.
- Air Conditioner
- A device that changes humidity levels, temperature or quality of air.
- Airflow Volume
- Measured in cubic feet per minute (cfm), this is the amount of air circulated in a space.
- Air Handler
- Parts of a system including the fan-blower, filter and housing.
- Air Conditioning, Heating and Refrigeration Institute
- American Society of Heating, Refrigeration and Air Conditioning Engineers
- British Thermal Unit measures the amount of heat required to raise or lower the temperature of one pound of water one degree Fahrenheit.
- British Thermal Units per hour
- The device that facilitates the combustion of air and gas.
- Burner Orifice
- The opening in the burner through which the gas or fuel passes prior to combustion.
- HVAC capacity is the output produced by the heating or cooling unit and is measured in BTUs per hour.
- A temperature scale that registers the freezing point of water as 0° and the boiling point as 100° under normal atmospheric pressure.
- Cubic Feet per Minute. A measurement of airflow volume
- Charging a System
- Adding coolant, or refrigerant, to an HVAC system.
- A pump that increases the pressure of gas.
- Vapor that is turned into a liquid as its temperature is lowered.
- Condenser Coil (Outdoor Coil)
- A device that removes heat from the refrigerant, allowing the refrigerant to be converted from vapor to liquid.
- Condenser Fan
- A fan that passes air over the condenser coil to facilitate the removal of heat from the refrigerant.
- Canadian Standards Association
- DC (Direct Current)
- A type of electrical current that only flows in one direction.
- Found at the exit point of ductwork, this plate usually contains grates that can be opened or closed to control the flow of air into a zone.
- Calculated by subtracting the average outdoor temperature for an area from 65° Fahrenheit. This measurement is used to estimate the amount of heating or cooling a home or building will need.
- A device that removes humidity, or moisture, from the air.
- A grille over an air supply duct with vanes that distribute the discharging air in a specific pattern or direction.
- Department of Energy
- Downflow Furnace
- A furnace with an intake on the top and an air discharge at the bottom.
- Drain Pan
- Also a condensate pan. As the refrigerant vapor is liquefied, the drain pan collects the condensate and funnels it to the drain line.
- Dry Bulb Temperature
- The temperature as measured without the consideration of humidity.
- A network of metal, fiberboard or flexible material flowing throughout a space which delivers air from an HVAC unit to the respective zones of a home or office.
- Energy Efficiency Ratio
- Environmental Protection Agency
- Expansion Valve
- A valve that meters the levels of refrigerant through a temperature or pressure control.
- Evaporator Coil (Indoor Coil)
- A device that is designed to absorb heat in the air in order to change the liquid refrigerant that flows through it into a vapor.
- A temperature scale in which water freezes at 32 degrees and boils at 212 degrees at normal atmospheric pressure.
- A device that creates airflow.
- A device that acts like a strainer to remove dirt or undesired particles.
- A vent that removes the byproducts of combustion from a furnace.
- The major component in heating a home. A device that facilitates the combustion of fuel and air to create heat.
- A delicate metal strip connecting two parts of an electrical circuit. This strip breaks, or melts, in the event of excess electrical charge, breaking the electrical circuit.
- Gas Appliance Manufacturers Association
- Heat Exchanger
- A device through which heat is transferred to a cold area or surface.
- Heat Gain
- The amount of heat added or created in a designated area.
- Heating Coil
- A coil that acts as a heat source for a heating system.
- Heat Loss
- The amount of heat subtracted from a designated area.
- Heat Pump
- A device used for either the heating or cooling of a space by transferring heat between two reservoirs.
- Heat Transfer
- Moving heat from one location to another.
- Heating Seasonal Performance Factor: This factor rates the efficiency of the heating portion of the heat pump.
- A device that adds humidity or moisture to the air.
- The device that measures humidity and turns the humidifier on and off.
- Dampness in the air caused by water vapor.
- Heating, Ventilation and Air Conditioning
- Elevating the temperature of a substance to the point of causing a combustion reaction.
- Kilowatt (kW)
- 1,000 watts
- Latent Heat
- A type of heat that when added to an area produces an effect other than an increase in temperature.
- The fine material of a filter that traps dirt, dust, mildew or bacteria.
- National Energy Council / National Electric Code
- National Electrical Manufacturing Association
- An opening or hole
- Package Unit
- A heating and cooling system contained in one outdoor unit.
- Pounds per square inch
- Pounds per square inch, absolute
- Pounds per square inch gauge
- Polyvinyl chloride; a type of plastic
- Reciprocating Compressor
- A type of compressor used in cooling systems to compress refrigerant by using a piston action.
- A chemical that condenses from a vapor to liquid and, in the process, decreases in temperature.
- Refrigerant Charge
- The amount of refrigerant in a system
- Seasonal Energy Efficiency Ratio: A rating system developed by the U.S. Government to indicate the efficiency level of cooling equipment.
- Self-contained System
- A package unity
- Sensible Heat
- Heat added or subtracted that causes a change in temperature.
- A device that reacts to a change in conditions.
- Split System
- An outdoor unit combined with an indoor unit.
- Sensors that monitor and control the output of an HVAC system.
- Thermostatic Expansion Valve
- A device that creates a constant evaporator temperature.
- One ton is 12,000 BTUs per hour.
- Upflow Furnace
- A furnace that pulls in air from the bottom and releases it through the top.
- A space where the pressure is significantly below that of standard atmospheric pressure.
- A unit of electro-motive force
- The force pushing electrical current along wires and cables.
- The unit of electrical power equal to the flow of one amp at a potential difference of one volt.
- Wet Bulb Thermometer
- A thermometer that measures the relative humidity in the air.
- A system that divides a home, office or space into different regions in order to better control the temperature and effectiveness of a heating and cooling system.