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.
|
ACCA
Air Conditioning Contractors of America.
|
Acoustical
Relating to sound, the science of sound, or a sense of hearing.
|
AFUE
Annual Fuel Utilization Efficiency. A measurement used to rate furnace efficiencies by dividing the ratio of heat output by heat input.
|
AGA
American Gas Association, Inc.
|
Air Conditioner
A device that changes humidity levels, temperature or quality of air.
|
Air Flow 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.
|
ARI
Air Conditioning and Refrigeration Institute.
|
ASHRAE
American Society of Heating, Refrigeration and Air Conditioning Engineers.
|
BTU
British Thermal Unit. Measures the amount of heat required to raise or lower the temperature of one pound of water one degree Fahrenheit.
|
BTUh
British Thermal Units per hour.
|
Burner
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.
|
Capacity
HVAC capacity is the output produced by the heating or cooling unit and is measured in BTUs per hour.
|
Celsius
A temperature scale that registers the freezing point of water as 0° and the boiling point as 100° under normal atmospheric pressure.
|
CFM
Cubic Feet per Minute. A measurement of airflow volume.
|
Charging a System
Adding coolant, or refrigerant, to an HVAC system.
|
Compressor
A pump that increases the pressure of gas.
|
Condensate
Vapor that is turned into a liquid as its temperature is lowered.
|
Condenser Coil
Also an 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.
|
CSA
Canadian Standards Association.
|
Damper
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.
|
DC
Direct Current. A type of electrical current that only flows in one direction.
|
Degree-Day
Calculated by subtracting the average outdoor temperature for an area from 65º Fahrenheit. This measurement is used to estimate the amount of heating or cooling a home or building will need.
|
Dehumidifier
A device that removes humidity, or moisture, from the air.
|
Diffuser
A grille over an air supply duct with vanes that distribute the discharging air in a specific pattern or direction.
|
DOE
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.
|
Ductwork
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.
|
EER
Energy Efficiency Ratio.
|
EPA
Environmental Protection Agency.
|
Evaporator Coil
Also an 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.
|
Expansion Valve
A valve that meters the levels of refrigerant through a temperature or pressure control.
|
Fahrenheit
A temperature scale in which water freezes at 32 degrees and boils at 212 degrees at normal atmospheric pressure.
|
Fan
A device that creates air flow.
|
Filter
A device that acts like a strainer to remove dirt or undesired particles.
|
Flue
A vent that removes the byproducts of combustion from a furnace.
|
Furnace
The major component in heating a home. A device that facilitates the combustion of fuel and air to create heat.
|
Fuse
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.
|
GAMA
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.
|
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 Coil
A coil that acts as a heat source for a heating system.
|
HSPF
Heating Seasonal Performance Factor. This factor rates the efficiency of the heating portion of the heat pump.
|
Humidifier
A device that adds humidity, or moisture, to the air.
|
Humidistat
The device that measures humidity and turns the humidifier on and off.
|
Humidity
Dampness in the air caused by water vapor.
|
HVAC
Heating, Ventilation and Air Conditioning.
|
Ignition
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.
|
Media
The fine material of a filter that traps dirt, dust, mildew or bacteria.
|
NEC
National Energy Council / National Electric Code.
|
NEMA
National Electrical Manufacturing Association.
|
Orifice
An opening or hole.
|
Package Unit
A heating and cooling system contained in one outdoor unit.
|
PSI
Pounds per square inch.
|
PSIA
Pounds per square inch, absolute.
|
PSIG
Pounds per square inch gauge.
|
PVC
Polyvinyl chloride; a type of plastic.
|
Reciprocating Compressor
A type of compressor used in cooling systems to compress refrigerant by using a piston action.
|
Refrigerant
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.
|
SEER
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 unit.
|
Sensible Heat
Heat added or subtracted that causes a change in temperature.
|
Sensor
A device that reacts to a change in conditions.
|
Split System
An outdoor unit combined with an indoor unit.
|
Thermostat
Sensors that monitor and control the output of an HVAC system.
|
Thermostatic Expansion Valve
A device that creates a constant evaporator temperature.
|
Ton
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.
|
Vacuum
A space where the pressure is significantly below that of standard atmospheric pressure.
|
Volt
A unit of electro-motive force.
|
Voltage
The force pushing electrical current along wires and cables.
|
Watt
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.
|
Zoning
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.
|