A
A-Coil (also known as evaporator coil): A heat exchanger that absorbs heat from the air, cooling it down.
AC (alternating current): A type of electrical current that changes direction regularly.
AC or DC: AC or direct current. AC is the type of electrical current that is used in most homes and businesses. DC is the type of electrical current that is produced by batteries and solar cells.
ACCA (Air Conditioning Contractors of America): A trade association for HVAC contractors.
Accoustical: Relating to sound.
AFUE (Annual Fuel Utilization Efficiency): A measure of how efficiently a heating system uses fuel.
AGA (American Gas Association): A trade association for the natural gas industry.
AHRI (Air Conditioning, Heating & Refrigeration Institute): A trade association for the HVAC industry.
Air cleaner (also known as air filtration system): A device that removes pollutants from the air.
Air conditioner: A device that cools the air.
Air filtration system (also known as air cleaner): A device that removes pollutants from the air.
Air flow volume: The amount of air that flows through a system in a given period of time.
Air handler: A device that circulates air through a heating and cooling system.
ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers): A professional organization for HVAC engineers.
B
BTU (British Thermal Unit): A unit of heat energy.
BTUh (British Thermal Unit per Hour): A unit of heat energy flow.
Burner: A device that ignites fuel and produces heat.
Burner orifice: A small opening in the burner through which fuel flows.
Burner (sealed combustion): A burner that is sealed from the air in the room, preventing combustion products from entering the room.
C
CADR (Clean Air Delivery Rate): A measure of how effectively an air cleaner removes pollutants from the air.
Capacity: The amount of heat or cooling that a system can produce.
Celsius: A temperature scale where 0 degrees is the freezing point of water and 100 degrees is the boiling point of water.
Certified Matched System: A heating and cooling system that has been certified by AHRI to be compatible and efficient when used together.
CFM (Cubic Feet per Minute): A unit of air flow volume.
Charge: The amount of refrigerant in a refrigeration system.
CleanEffects™ (also Trane CleanEffects™): A proprietary air filtration system developed by Trane that removes pollutants from the air, including pollen, dust, smoke, and bacteria.
Comfort™ coil (also evaporator coil or indoor coil): A heat exchanger that absorbs heat from the air, cooling it down.
Compressor: A device that compresses refrigerant gas, increasing its pressure and temperature.
Condensate: The liquid that is formed when refrigerant gas condenses.
Condenser coil (or outdoor coil): A heat exchanger that releases heat from refrigerant gas, causing it to condense.
Condenser fan: A fan that blows air over the condenser coil, helping to remove heat.
Contactor: A switch that controls the flow of electricity to the compressor.
Crankcase heater: A device that heats the compressor crankcase, preventing oil from thickening in cold weather.
CSA (Canadian Standards Association): A non-profit organization that develops and publishes standards for products and services in Canada.
D
Damper: A device that controls the flow of air through a duct system.
DB (Decibels): A unit of measurement for sound intensity.
DC (direct current): A type of electrical current that flows in one direction only.
Defrost: The process of removing ice from the evaporator coil.
Degree-day: A unit of measurement for heating and cooling energy consumption.
Dehumidifier: A device that removes moisture from the air.
Diffuser: A device that distributes air evenly throughout a room.
DOE (Department of Energy): A United States government agency that is responsible for developing and enforcing energy efficiency standards.
Downflow furnace: A furnace that blows heated air down into the room.
Drain pan: A pan that collects condensate from the evaporator coil.
Dry bulb temperature: The temperature of the air as measured by a dry bulb thermometer.
Dry bulb thermometer: A thermometer that measures the temperature of the air without taking humidity into account.
Dual compressors: Two compressors that are used in a single HVAC system. Dual compressors can provide more efficient and precise cooling and heating than a single compressor.
Ductwork: A system of ducts that distributes heated and cooled air throughout a building.
DX (direct expansion): A type of HVAC system that uses refrigerant to cool and heat the air.
E
Ecologic: A Trane product line that is designed to be environmentally friendly. Ecologic products use energy-efficient technologies and environmentally friendly materials.
EER (Energy Efficiency Ratio): A measure of how efficiently an air conditioner or heat pump uses electricity.
Electronic Air Cleaner (EAC): A device that removes pollutants from the air using an electric field.
Energy recovery ventilator (also FreshEffects™ or Trane FreshEffects™): A device that exchanges heat and moisture between indoor and outdoor air, helping to reduce energy consumption.
EPA (United States Environmental Protection Agency): A federal agency that is responsible for protecting the environment.
Evaporator coil (also Comfort™ Coil or Indoor coil): A heat exchanger that absorbs heat from the air, cooling it down.
Expansion valve: A device that controls the flow of refrigerant into the evaporator coil.
F
Fahrenheit: A temperature scale where water freezes at 32 degrees and boils at 212 degrees.
Fan: A device that circulates air.
Filter: A device that removes pollutants from the air.
Flue: A passage that carries combustion products away from a furnace or water heater.
FreshEffects™ (also Energy Recovery Ventilator or Trane FreshEffects™): A proprietary energy recovery ventilator developed by Trane.
Furnace: A device that heats the air in a building.
Fuse: A safety device that protects electrical circuits from overload.
G
GAMA (Gas Appliance Manufacturers Association): A trade association for the gas appliance industry.
Gas furnace heat exchanger: A heat exchanger that transfers heat from the combustion of natural gas to the air.
H
Heat exchanger: A device that transfers heat from one fluid to another.
Heat gain: The amount of heat that enters a building from the outside.
Heat loss: The amount of heat that escapes from a building to the outside.
Heat pump: A device that can be used to heat or cool a building by transferring heat between the indoor and outdoor air.
Heat transfer is the movement of thermal energy from one body to another because of a temperature difference. Heat can be transferred in three ways: conduction, convection, and radiation.
Heating coil is a device that uses electricity to heat the air. Heating coils are commonly used in furnaces, air conditioners, and heat pumps.
HEPA filter (high-efficiency particulate air filter) is a type of air filter that removes very small particles from the air, including dust, pollen, and smoke. HEPA filters are commonly used in hospitals and other cleanroom environments.
Hertz (Hz) is the unit of frequency, which is the number of cycles per second. The frequency of an alternating current (AC) is measured in hertz. For example, the frequency of the electrical power in North America is 60 Hz.
Horizontal flow is a type of airflow in which the air flows horizontally through a heating or cooling system. Horizontal flow systems are commonly used in central heating and air conditioning systems.
HSPF (heating seasonal performance factor) is a measure of the efficiency of a heat pump. HSPF is calculated by dividing the total heat output of a heat pump over a heating season by the total energy input.
Humidifier is a device that adds moisture to the air. Humidifiers are commonly used in dry climates to help relieve dry skin, itchy eyes, and other symptoms of dry air.
Humidistat is a device that controls the humidity level in a room. Humidistats are commonly used in conjunction with humidifiers to maintain a comfortable humidity level.
Humidity is the amount of moisture in the air. Humidity can be measured in two ways: absolute humidity and relative humidity.
Humidity, absolute is the amount of water vapor in the air, expressed as a mass per unit volume. For example, the absolute humidity of air at 20 degrees Celsius and 50% relative humidity is 10.5 grams of water per cubic meter of air.
Humidity, relative is the amount of water vapor in the air compared to the maximum amount of water vapor that the air can hold at that temperature. For example, the relative humidity of air at 20 degrees Celsius and 50% relative humidity is 50%. This means that the air is holding half of the maximum amount of water vapor that it can hold at that temperature.
HVAC (Heating, Ventilation, and Air Conditioning): A system that controls the temperature, humidity, and air quality in a building.
Hybrid heat (also Hybrid System): A heating and cooling system that uses two different types of energy sources, such as electricity and natural gas. Hybrid heat systems are more efficient than traditional systems, which can save you money on your energy bills.
Hybrid system (also Hybrid Heat): See Hybrid heat.
I
Ignition (also electric ignition): The process of starting a flame in a furnace or boiler. Electric ignition is the most common type of ignition used in HVAC systems.
Indoor coil (also Comfort™ Coil or evaporator coil): A heat exchanger that absorbs heat from the air, cooling it down. The indoor coil is located in the air handler unit.
Indoor/Outdoor system (also split system): An HVAC system that has two separate units: an indoor air handler unit and an outdoor condensing unit. Split systems are the most common type of HVAC system used in homes and businesses.
Inverter Compressor: A type of compressor that uses variable frequency technology to adjust the speed of the compressor motor. Inverter compressors are more efficient and quieter than traditional compressors.
L
Latent heat: The heat that is absorbed or released when a substance changes state, such as from a liquid to a gas or from a gas to a solid. Latent heat is responsible for the cooling effect of evaporation and the heating effect of condensation.
Load calculation: A process of determining the heating and cooling requirements of a building. Load calculations are used to select the right size HVAC system for the building.
M
Matched system: An HVAC system that has been designed to work together efficiently. Matched systems typically consist of a furnace or heat pump, air conditioner, and air handler unit.
Media: The material that is used to filter the air in an HVAC system. Media can be made from a variety of materials, such as fiberglass, pleated paper, and electrostatic filters.
N
NATE (North American Technician Excellence): A non-profit organization that certifies HVAC technicians.
NEC (National Electrical Code): A set of standards that govern the installation of electrical wiring and equipment.
NEMA (National Electrical Manufacturers Association): A trade association for the electrical industry.
O
OEM (Original Equipment Manufacturer): The manufacturer of a piece of equipment.
Operating cost: The cost of operating an HVAC system. Operating costs include the cost of energy, maintenance, and repairs.
Orifice: A small opening in a pipe or duct that restricts the flow of fluid or air. Orifices are used in HVAC systems to control the flow of refrigerant and air.
Outdoor coil (also Condenser coil): A heat exchanger that releases heat from the refrigerant gas, causing it to condense. The outdoor coil is located in the condensing unit.
P
Packaged system (or Packaged unit): An HVAC system that has all of the components (furnace, air conditioner, and air handler) in a single unit. Packaged systems are typically used in smaller homes and businesses.
Payback analysis: A method of evaluating the cost-effectiveness of an investment, such as an HVAC system. Payback analysis is calculated by dividing the initial cost of the investment by the annual savings that the investment will generate.
PSI (pounds per square inch): A unit of pressure equal to the force of 1 pound acting on an area of 1 square inch.
PSIA (pounds per square inch absolute): A unit of pressure that is measured relative to a vacuum. PSIA is used to measure the pressure of refrigerant in an HVAC system.
PSIG (pounds per square inch gauge): A unit of pressure that is measured relative to atmospheric pressure. PSIG is used to measure the pressure of air in an HVAC system.
PVC (polyvinyl chloride): A type of plastic that is used in a variety of HVAC applications, such as pipe fittings and ducts.
R
Reciprocating compressor: A type of compressor that uses a piston to compress refrigerant gas.
Reclaiming: The process of removing refrigerant from an HVAC system and cleaning it so that it can be reused.
Recycling: The process of converting refrigerant into a new product, such as plastic.
Refrigerant: A substance that is used to absorb and release heat, making it possible to cool or heat a building. Refrigerants are typically gases or liquids that have a low boiling point.
Refrigerant charge: The amount of refrigerant that is contained in an HVAC system.
Refrigerant lines: The pipes that carry refrigerant between the different components of an HVAC system.
S
SEER (Seasonal Energy Efficiency Ratio): A measure of the efficiency of an air conditioner or heat pump. SEER is calculated by dividing the total cooling output of a unit over a cooling season by the total energy input.
Self-contained system: An HVAC system that has all of the components (furnace, air conditioner, and air handler) in a single unit. Self-contained systems are typically used in smaller homes and businesses.
Sensible heat: The heat that is transferred to or from a substance without changing its state. Sensible heat is responsible for the feeling of warmth or coldness.
Sensor: A device that detects changes in a physical quantity, such as temperature or pressure. Sensors are used in HVAC systems to control the operation of the system.
Setpoint: The desired temperature or humidity level that is set on a thermostat.
Spine-Fin™ coil: A type of heat exchanger that is used in some HVAC systems. Spine-Fin™ coils are known for their high efficiency and durability.
Split system (also indoor/outdoor system): An HVAC system that has two separate units: an indoor air handler unit and an outdoor condensing unit. Split systems are the most common type of HVAC system used in homes and businesses.
T
Thermostat: A device that controls the temperature of an HVAC system.
Thermostatic expansion valve: A device that controls the flow of refrigerant into the evaporator coil. The thermostatic expansion valve is controlled by the temperature of the evaporator coil.
Ton: A unit of cooling capacity equal to 12,000 BTU/hour.
Trane CleanEffects™ (also CleanEffects™): A proprietary air filtration system developed by Trane that removes pollutants from the air, including pollen, dust, smoke, and bacteria.
Trane FreshEffects™ (also Energy Recovery Ventilator or FreshEffects™): A proprietary energy recovery ventilator developed by Trane that exchanges heat and moisture between indoor and outdoor air, helping to reduce energy consumption.
Two-stage compressor: A type of compressor that can operate at two different speeds. Two-stage compressors are more efficient than single-stage compressors and can provide more precise temperature control.
Two-stage heating/Two-stage cooling: An HVAC system that has a two-stage compressor and a two-stage furnace or air conditioner. Two-stage heating and cooling systems are more efficient and can provide more precise temperature control than single-stage systems.
U
U-Factor: A measure of the heat transfer rate through a building material. The lower the U-Factor, the better the insulating properties of the material.
UL (Underwriters Laboratories): A non-profit organization that tests and certifies products for safety.
Upflow furnace: A furnace that blows heated air up into the room.
V
Vacuum: A region of space where the pressure is significantly below atmospheric pressure.
Volt: A unit of electrical potential equal to the potential difference between two points that will cause a current of 1 ampere to flow when connected by a conductor.
Voltage: The potential difference between two points in an electrical circuit.
W
Watt: A unit of power equal to 1 joule per second.
Wet Bulb Thermometer: A thermometer that measures the temperature of the air when it is saturated with moisture. Wet bulb temperature is used to calculate humidity.
Z
Zoning: The division of a building into different temperature zones. Zoning allows for more precise temperature control and can save energy.
Zoning System: A system that allows you to control the temperature of different zones in a building. Zoning systems typically use dampers to control the flow of air to each zone.