Glossary

AC

An abbreviation for air conditioning.

ACCA

ACCA (Air Conditioning Contractors of America) is the association of HVAC (heating, ventilation, air conditioning, building performance) contractors.

AIR CLEANER

Whole home air purifiers remove pollutants from every room for a healthier and more comfortable home.

AIR CONDITIONER

A system for controlling the humidity, ventilation, and temperature in a building or vehicle, typically to maintain a cool atmosphere in warm conditions.

AIR CONDITIONING

A system for controlling the humidity, ventilation, and temperature in a building or vehicle, typically to maintain a cool atmosphere in warm conditions.

ATTIC FAN

A powered attic ventilator, or attic fan, is a ventilation fan which regulates the heat level of a building's attic by exhausting hot air. A thermostat is used to automatically turn the fan off and on, while sometimes a manual switch is used. An attic fan can be gable mounted or roof mounted.

AIR FILTER 

A particulate air filter is a device composed of fibrous materials which removes solid particulates such as dust, pollen, mold, and bacteria from the air.

AIR HANDLER

An air handler is a large metal box containing a blower, heating or cooling elements, filter racks or chambers, sound attenuators, and dampers. 

Air handlers connect to a ductwork ventilation system that distributes the conditioned air through the building and returns it to the air handling unit (AHU)

BOILER

A fuel-burning apparatus or container for heating water, in particular. Household device providing a hot-water supply or serving a central heating system. Tank for generating steam under pressure in a steam engine.

CAPACITOR

Capacitors send a jolt to start up the motor, or a regular series of jolts to keep the motor working. Capacitors in an air conditioner work with three different motors: the compressor, the blower motor, and the outside fan.

COMPRESSOR

The system refrigerant starts its cycle in a gaseous state. The compressor pumps the refrigerant gas up to a high pressure and temperature. From there it enters a heat exchanger (sometimes called a condensing coil or condenser) where it loses energy (heat) to the outside, cools, and condenses into its liquid phase.

CONDENSER

In systems involving heat transfer, a condenser is a device or unit used to condense a substance from its gaseous to its liquid state, by cooling it

CONDENSATE LINE

Is a device used to remove condensed water from a fluid process or HVAC system.

DAMPER

A damper is a valve or plate that stops or regulates the flow of air inside a duct, chimney, VAV box, air handler, or other air-handling equipment.

A damper may be used to cut off central air conditioning (heating or cooling) to an unused room, or to regulate it for room-by-room temperature and climate control.

DIGITAL THERMOSTAT

A programmable thermostat is a thermostat which is designed to adjust the temperature according to a series of programmed settings that take effect at different times of the day. Programmable thermostats may also be called setback thermostats or clock thermostats.

DIGITAL NON-PROGRAMMABLE THERMOSTAT

A thermostat is a device that senses the current temperature and then manipulates a heating and cooling system based on that temperature's relationship to a set point. In residential and commercial scenarios, the two main classifications of thermostats are programmable and non-programmable.

DOWNFLOW FURNACE

These terms refer to the direction the air flows as it is taken in and heated by the furnace. So in an upflow furnace, the cool air is taken in at the bottom, warmed, and then expelled at the top. A downflow furnace, on the other hand, takes in cool air at the top and expels heated air at the bottom

DUCTLESS MINI SPLIT

Like central systems, mini splits have two main components: an outdoor compressor/condenser, and an indoor air-handling unit. A conduit, which houses the power cable, refrigerant tubing, suction tubing, and a condensate drain, links the outdoor and indoor units.

DUCTWORK

Ducts are conduits or passages used in heating, ventilation, and air conditioning (HVAC) to deliver and remove air. The needed airflows include, for example, supply air, return air, and exhaust air. Ducts commonly also deliver ventilation air as part of the supply air. A duct system is also called ductwork. EER (Energy Efficiency Ratio) means the ratio of the cooling capacity of the air conditioner in British Thermal Units per hour, to the total electrical input in watts under ARI-specified test conditions (95 degrees Fahrenheit).

EPA

The Environmental Protection Agency (EPA) was established in December 1970 under United States President Richard Nixon. The EPA is an agency of the United States federal government whose mission is to protect human and environmental health.

ENERGY STAR PROGRAM

Energy Star is a government-backed labeling program that helps people and organizations save money and reduce greenhouse gas emissions by identifying factories, office equipment, home appliances and electronics that have superior energy efficiency.

EVAPORATOR COIL

A series or network of tubes filled with refrigerant located inside the home that take heat and moisture out of indoor air as liquid refrigerant evaporates.

EXPANSION VALVE

Type of metering device that controls the flow of refrigerant in a system.

FILTER

Air cleaning and filtration removes particles, contaminants, vapors and gases from the air. The filtered and cleaned air then is used in heating, ventilation and air conditioning. Air cleaning and filtration should be taken in account when protecting our building environments.

FLAME SENSOR

Its purpose is to provide the flame needed to light the gas coming out of the main burner. When the furnace "turns on", a valve releases gas into the burner and the pilot light ignites that gas.

FLUE

A flue is a duct, pipe, or opening in a chimney for conveying exhaust gases from a fireplace, furnace, water heater, boiler, or generator to the outdoors. Historically the term flue meant the chimney itself.

FURNACE

An appliance fired by gas, oil, or wood in which air or water is heated to be circulated throughout a building in a heating system.

GLYCOL-COOLED SYSTEM

A type of air conditioning system that uses Freon as a refrigerant and a water/glycol solution as a condensing medium. Typically, the glycol-cooled condenser is located inside the air conditioner with the rest of the refrigeration components. Water/glycol is piped to the unit from a dry cooler or other suitable source. The glycol keeps the solution from freezing during winter operation.

HEAT PUMP

Installation for this type of system typically consists of two parts: an indoor unit called an air handler and an outdoor unit similar to a central air conditioner, but referred to as a heat pump. A compressor circulates refrigerant that absorbs and releases heat as it travels between the indoor and outdoor units.

HEAT EXCHANGER

A furnace's heat exchanger is a set of tubes or coils that are looped repeatedly through the air flow inside your furnace for the purpose of heating air. Simply put, the furnace heat exchanger is the part of your furnace that actually heats the air.

HEATING COIL

A coil of wire heated by the passage of an electric current and used for producing and maintaining a high temperature in various scientific operations or for industrial purposes.

HEPA FILTER

Being, using, or containing a filter usually designed to remove 99.97 percent of airborne particles measuring 0.3 micrometers or greater in diameter passing through it.

HORIZONTAL FURNACE

A furnace that lies on its side, pulling in return air from one side and expelling warm air from the other HSPF (Heating Seasonal Performance Factor): This factor rates the efficiency of the heating portion of the heat pump.

HOT WATER HEATER

An apparatus for heating and usually storing hot water (as for domestic use).

HUMIDIFICATION

The process of adding moisture to the air within a space.

INSULATION

Any material that slows down the transfer of heat.

LINE SET

The pipe between the outside unit and inside unit on a split system air conditioner.

LOAD CALCULATION

A mathematical design tool used to determine the heat gain and heat loss in a building so that properly sized air conditioning and heating equipment may be installed.

MANUAL THERMOSTAT

A thermostat is used to control the temperature of heating and cooling systems. A manual thermostat is an excellent way to keep temperature inside a room to the required level. There are different types of thermostat systems. Digital programmable units are preferred but many people still want to use manual thermostats.

MATCHED SYSTEM

A heating and cooling system comprised of products that have been certified to perform at promised comfort and efficiency when used together, and used according to design and engineering specifications.

OUTDOOR COIL/CONDENSING UNIT

The portion of a heat pump or central air conditioning system that is located outside the home and functions as a heat transfer point for collecting heat from and dispelling heat to the outside air.

PACKAGE SYSTEM

A piece of air conditioning and heating equipment where all components are located in one cabinet. Used occasionally in residential applications, the package unit is installed either beside or on top of the home.

PACKAGED SYSTEM

A self-contained heating and/or air conditioning system.

PLENUM

Air compartment connected to a duct or ducts. Air flow passage made of duct board, metal, drywall, or wood. Joins supply and return ducts with HVAC equipment. The portions of the air distribution system that makes use of the building structure, and the sheet meal that connects distribution ductwork to an air handling unit. Many buildings use the space above a dropped ceiling as a plenum.

PREVENTIVE MAINTENANCE

Regular HVAC preventive maintenance is the best way to ensure trouble-free operation and peak performance. Pre-season maintenance is also important. It can help to avoid a system failure in severe hot or cold weather when you need it most, and it can also keep your energy bill from getting out of control.

REFRIGERANT

Chemical used in a cooling mechanism, such as an air conditioner or refrigerator, as the heat carrier which changes from gas to liquid and the back to gas in the refrigeration cycle.

REFRIGERANT LINES

The lines that carry the refrigerant between the evaporator and condenser coils and through the compressor and expansion device typically are copper. The larger line typically carries a cool gas and is insulated. This is commonly referred to as the suction line, but it is also called the return line or vapor line.

REMOTE ACCESS THERMOSTAT

An Internet thermostat is a programmable building thermostat capable of connecting to an Internet protocol (IP) network. Through an IP connection, you can remotely send instructions to an Internet thermostat to turn it on or off or change its programming.

SEER

The Seasonal Energy Efficiency Ratio (SEER) measures air conditioning and heat pump cooling efficiency, which is calculated by the cooling output for a typical cooling season divided by the total electric energy input during the same time frame. A higher SEER rating means greater energy efficiency.

SMART THERMOSTAT

Smart thermostats are devices that can be used with home automation and are responsible for controlling a home's heating and/or air conditioning. ... Like a connected thermostat they are connected to the Internet, they allow users to adjust heating settings from other internet-connected devices, such as smartphones.

THERMOCOUPLE

A thermocouple is a device that consists of a pair of strips of metal made from different material. It is installed so that its ends are in the pilot light of the furnace. The thermocouple in a gas furnace is designed to keep the gas valve open through its electric voltage

THERMOSTAT

A device that automatically regulates temperature, or that activates a device when the temperature reaches a certain point.

TOUCHSCREEN THERMOSTAT

A programmable thermostat is a thermostat which is designed to adjust the temperature. The selection of which days are defined as the "weekend" is arbitrary, depending on the user's heating and cooling schedule requirements.

TWO STAGE HEATING

Traditional single-stage furnaces are designed to heat your home during the absolute coldest weather in your geographic area. Therefore, they run at their fullest capacity whenever they are in operation, regardless of the temperature outside. A two-stage furnace has two heating stages: low and high.

UPFLOW FURNACE

The term air flow configuration describes the physical orientation of a furnace relative to the direction in which heated air leaves the furnace and enters the ductwork. The most common terms used to describe the air flow configuration are: upflow, downflow, and horizontal.

WATER HEATER

An apparatus for heating and usually storing hot water (as for domestic use).

WIRELESS-WIFI THERMOSTAT

A WiFi thermostat works in conjunction with your heating, ventilation and air conditioning (HVAC) system. While a standard thermostat acts as a control panel for your home's heating and air conditioning system, a programmable thermostat can be adjusted from a remote location.

ZONING SYSTEM

Zoning and Zone Control of Heating, Ventilating and Air Conditioning (HVAC) Systems are two ways of saying individual temperature control from one central HVAC System. Typically with almost all forced airsystems there is only one thermostat to control the heating and cooling.