Glossary of Terms

  • AFUE
    Annual Fuel Utilization Efficiency
  • AIR CLEANER
    Removes unwanted particles from moving air.
  • AIR CONDITIONER
    A system for controlling the humidity, ventilation, and temperature in a confined space.
  • AIR HANDLER
    The indoor unit on a heat pump system that contains the blower, evaporator and the auxiliary heat.
  • ARI
    Air-Conditioning and Refrigeration Institute is a non-profit, voluntary organization comprised of heating, air conditioning and refrigeration manufacturers...
  • ASHRAE
    American Society of Heating, Refrigeration, and Air Conditioning Engineer.
  • BLOWER
    HVAC blower motors move the air through the system. The blower motor is sized based on the amount of air flow necessary for the system.
  • BTU
    British Thermal Unit, is the measure of heat given off when fuel is combusted. Used for both heating and cooling. One BTU is the equivalent of the heat given off by one kitchen match.
  • BTUH
    British Thermal units per hour. 12,000 BTUh equals one ton of cooling.
  • BURNERS
    Furnace burner is the point in a furnace where a mixture of air and fuel is burned to produce heat. There are several different types of furnaces...
  • CAPACITOR
    An electrical device characterized by its capacity to store an electric charge. There are two basic types of motor capacitors most commonly used in...
  • CAPACITY
    The ability of a heating or cooling system to cool or heat a given amount of space.
  • CELCIUS
    The metric temperature scale in which water freezes at zero degrees and boils at one hundred degrees. Designated by the symbol “C”.
  • CFM
    The abbreviation for cubic feet per minute. Commonly used to measure the rate of airflow in an air conditioning system.
  • CHARGE
    Adding refrigerant to a system.
  • CIRCUIT / CONTROL BOARD
    The brain of the furnace. The board is made up of resistors, fuses, and electrical circuits. It controls all the electrical aspects of the system.
  • CO / CO DETECTOR
    Carbon monoxide is an odorless, tasteless, invisible gas. Carbon monoxide is present in low levels in the air. In the home, it is formed from...
  • COMPRESSOR
    A scroll compressor uses two interleaved scrolls to pump, compress, or pressurize fluids such as liquids and gases. The vane geometry may be...
  • CONDENSATE
    Vapor that liquefies due to the lowering of its temperature to the saturation point.
  • CONDENSER COIL
    The compressor needs to create a lot of force because the condenser is a pressurized coil. The refrigerant is compressed and packed tightly...
  • CONDENSER FAN
    The condenser fan motor is responsible for pulling air through coils of the condenser. The are also call air conditioner fan motor or heat pump fan motor but...
  • CONTACTOR
    A contactor or relay is an electrical device that takes a control signal usually 12 volts DC, 24, 120, 208-230 volts ac and creates a magnetic field to pull in a set of...
  • CRANKCASE HEATER
    The electric resistance heater installed on compressor crankcases to keep the crankcase oil at a temperature higher than the coldest part of the system to prevent migration.
  • DAMPER
    A movable plate that opens and closes to control airflow.
  • Defrost Cycle
    When a heat pump is operating in the heating mode or heat cycle, the outdoor air is relatively cool and the outdoor coil acts as an evaporator.
  • DEHUMIDIFIER
    Installed as part of your home's heating and cooling system, A central dehumidifier pulls air from every room in your home through the return ducts.
  • DRAIN PAN
    Pan used to catch and collect condensate.
  • DUCTWORK
    A pipe or conduit through which air is supplied. Typically made of metal, fiberboard, or a flexible material.
  • EMERGENCY HEAT / AUX. HEAT
    The balance point (when it can no longer efficiently transfer heat from the outside air) of an air source heat pump, is usually about 35 degrees.
  • ENERGY STAR
    An EPA designation attached to HVAC products that have efficency performance above the standard government minimums.
  • EPA
    Environmental Protection Agency
  • EVAPORATOR COIL
    Part of a split system air conditioner or heat pump located indoors. The evaporator coil cools and dehumidifies the air by converting liquid refrigerant into...
  • EXPANSION VALVE
    A variable metering device that varies refrigerant flow based on cooling demand. As demand increases, the valve opens wider to permit more...
  • FAN
    Any device that creates air.
  • FARENHEIT
    The temperature scale on which water freezes at 32 degrees and boils at 212 degrees. Designated by the symbol “F”.
  • FILTER
    The main function of an air filter is to keep the air that is being circulated in your home, free from pollutants. There are the standards air filters, the pleated filters,...
  • FILTER DRIER
    The filter-drier is an accessory that performs the functions of filtering out particles and removing and holding moisture to prevent it from circulating through the system.
  • FLUE
    A vent that carries the products of combustion from a furnace.
  • FURNACE
    The part of an environmental system that converts gas, oil, electricity or other fuel to heat for distribution within a confined space.
  • GAS VALVE
    A valve that controls fuel flow to the burner in a gas-fired furnace or heater.
  • HEAT EXCHANGER
    The heat exchanger is a series of tubes or ribbons on the furnace that separates the fire and hot gases from the air passing over it. The combustion process on a gas furnace produces Carbon Monoxide or CO...
  • HEAT PUMP
    An automated compression cycle refrigeration system that can be switched to either heat or cool the controlled space.
  • HEAT TRANSFER
    The movement of energy from one area to another.
  • HSPF
    The Heating Seasonal Performance Factor is a measure of heating efficiency of a heat pump.
  • HUMIDIFIER
    A Whole-House Humidifier is installed directly to your central new or existing heating and cooling system. Humidity is introduced into your home’s air in the...
  • HUMIDISTAT
    A humidity sensing device designed to regulate humidity input to reacting to changes in moisture of the air.
  • HVAC
    Heating, Ventilating, and Air Conditioning.
  • INDOOR COIL
    See Evaporator Coil
  • LINE SETS
    The copper tube that runs from the evaporator coil to the outdoor unit that refrigerant travels through.
  • MEDIA
    The material in a filter that traps and holds the impurities.
  • MERV RATING
    The MERV (Minimum Efficiency Reporting Value) rating of size of particles allowed through. The higher the MERV rating, the smaller the holes, the higher the efficiency.
  • MINI-SPLIT SYSTEM
    A ductless air conditioning system that mounts in a single room, used to cool individual desired or no windows are present.
  • OEM
    Original Equipment Manufacturer.
  • OUTDOOR COIL
    See Condenser Coil.
  • PACKAGE UNIT
    A heating and cooling system contained in one outdoor cabinet.
  • PROGRAMMABLE THERMOSTAT
    A thermostat with the ability to record different temperature/time settings for your HVAC system.
  • PSI
    Pounds per square inch.
  • REFRIGERANT
    absorbs heat in evaporator by change of state from a liquid to a gas, and releases its heat in a condenser as the substance returns from...
  • REFRIGERANT LINES
    Two copper lines that connect the outdoor air conditioner or heat pump to the indoor evaporator coil.
  • REVERSING VALVE
    A reversing valve is a component in a heat pump, that changes the direction of refrigerant flow. By reversing the flow of refrigerant...
  • SEER
    The Seasonal Energy Efficiency Ratio is a measure of the cooling efficiency of a air conditioner or heat pump.
  • SPLIT SYSTEM
    The combination of an outdoor unit with an indoor unit.
  • SPLIT SYSTEM
    An HVAC system in which some components are located inside the structure of the house and some of the outside of the structure.
  • THERMOSTAT
    A device for regulating the temperature of a system so that the system's temperature is maintained near a desired set point temperature.
  • TON
    A unit of measurement used for determining the cooling capacity of a system. One ton of cooling is based on the amount of heat needed to melt one ton of ice in a 24 hour period.
  • TWO STAGE OPERATION
    Provides two levels of heating or cooling output for greater temperature control and energy efficiency.
  • TXV
    Thermostatic (or Thermal) Expansion Valve is a precision device used to meter the flow of liquid refrigerant entering the evaporator at a rate that matches the amount of refrigerant being boiled off the evaporator.
  • UPFLOW
    When a furance or air handler is installed in an upright position.
  • UV LIGHT / GERMICIDAL LIGHT
    UV lights are mounted inside your system, near the cooling coil, where fungus and microbes may grow and pollutants can build up.
  • VACUUM
    A pressure below atmospheric pressure.
  • VARIABLE SPEED MOTOR
    A motor that automatically adjusts the flow of warm or cool air for ultimate comfort.
  • ZONE SYSTEMS