A

Air Changes Per Hour (ACH)

The hourly ventilation rate divided by the volume of a space. For perfectly mixed air or laminar flow spaces, this is equal to the number of times per hour that the volume the space is exchanged by mechanical and natural ventilation.

Air Handler (AH) / Coil Blower

The indoor part of an air conditioner or heat pump that moves cooled or heated air throughout the ductwork of your home. An air handler is usually a furnace or a blower coil.

Air Conditioner

An appliance, system, or mechanism designed to dehumidify and extract heat from an area. Usually this term is reserved for smaller self contained units such as a residential system.

Air Conditioning And Refrigeration Institute (ARI)

An industry trade association that develops standards for measuring and certifying product performance. For instance, ARI Standard 270 provides guidelines for establishing sound levels for outdoor air-conditioning equipment.

Annualized Fuel Utilization Efficiency (AFUE)

A measure of furnace heating efficiency. The higher the AFUE, the more efficient the furnace.

B

Bioaerosol

The (short for Biological Aerosol) is a suspension of airborne particles that contain living organisms or were released from living organisms. These particles are very small and range in size from less than one micrometer (0.00004") to one hundred micrometers (0.004").

British Thermal Unit (BTU)

A measurement of heat energy. One Btu is the amount of heat required to raise one pound of water by one degree Fahrenheit. The higher the Btu rating, the greater the heating capacity of the system.

British Thermal Unit Per Hour (BTUh)

British thermal units per hour.

Boiler

An appliance intended to supply hot liquid or vapour for space-heating, processing, or power purposes; does not include appliances certified as water heaters.

C

Carbon Monoxide

An odorless, colorless, tasteless, poisonous and flammable gas produced when carbon burns with insufficient air.

Central Air-Conditioning System

System in which air is cooled at a central location and distributed to and from rooms by one or more fans and a series of ducts.

Combined Annual Efficiency (CAE)

A measure of the amount of heat produced for every dollar of fuel consumed for both home and water heating.

Communication Module

A component that shows the system status and environmental benefits in real time.

Compressor

The part of an outdoor air conditioner or heat pump that compresses and pumps refrigerant to meet household cooling requirements.

Condenser Coil

The outdoor portion of an air conditioner or heat pump that either releases or collects heat, depending on the time of the year.

Cubic Feet Per Minute (CFM)

A measurement of how many cubic feet of air pass by a stationary point in one minute. The higher the number, the more air is being moved through the ductwork by the system.

D

Damper

A movable plate, located in the ductwork, that regulates airflow and directs it to areas that need it most. Typically used in a zoning application.

Decibel (dB)

A unit used to measure the relative intensity of sound.

Dry-Charged Unit

An air-conditioner or heat pump that is shipped dry and charged with refrigerant at the place of installation. Dry-charged units are appropriate for homeowners who need a replacement unit compatible with R-22 refrigerant.

Dual Fuel

A comfort system that pairs an electric heat pump with a gas furnace and alternates between the two fuel sources to maximize comfort and efficiency.

Ductwork

A system of ducts used for a particular purpose, as in a ventilation or heating system. (e.g.) air that is channeled from the furnace or the blower coil throughout your home.

E

Electronic Air Cleaner

An electronic device that filters out large particles and bioaerosols in indoor air.

Energy Star®

A designation of the U.S. Environmental Protection Agency (EPA). Attached to HVAC products that meet or exceed federal guidelines for energy-efficient performance.

Environmental Protection Agency (EPA)

An agency of the U.S. government that develops and enforces federal environmental regulations and oversees the nationwide ENERGY STAR® program.

Evaporator Coil

The part of an air conditioner or heat pump that absorb the heat from the air in your house. It is located inside the air handler or attached to the furnace.

F

Fresh air intake (FAI)

An opening through which outside air is drawn into the building. This may be to replace air in the building that has been exhausted by the ventilation system, or to provide fresh air for combustion of fuel.

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.

Furnace Filter

A device located between the return air vent and the furnace, its funtions in protecting the furnace motor, mechanical parts and also improve indoor air quality by trapping the dust, pollen, smoke, and other indoor pollutants. They can be of the media, electrostatic or electronic type.

G

Garage Heaters

Natural or propane gas units that provide warmth for car garages of almost any size during the winter months. Separated combustion models provide heating for hard-to-heat applications.

Grille

A facing across a duct opening, often rectangular in shape, containing multiple parallel slots through which air may be delivered or withdrawn from a ventilated space. The grille directs the air flow in a particular direction and prevents the passage of large items.

H

Heat Exchanger

A heating component that’s located in the furnace and transfers heat to the surrounding air, which is then pumped throughout the home.

Heat Pump

An HVAC unit that heats or cools by moving heat. During the winter, a heat pump draws heat from outdoor air and circulates it through a home's air ducts. In the summer, it reverses the process and removes heat from the house and releases it outdoors.

Heating Seasonal Performance Factor (HSPF)

The heating efficiency rating for heat pumps. The higher the rating, the more efficient the heat pump.

Horizontal Flow

Describes an air handler or furnace that is positioned on its side and circulates air in one end and out the other. Ideal for attic or crawl space installations.

Humidifier

An indoor air quality product that adds moisture to heated air as it passes from the furnace into the ductwork for distribution throughout the home.

Humidistat

An automatic device used to maintain humidity at a fixed or adjustable set point.

HVAC

Heating, Ventilation and Air Conditioning.

HVAC/R

Heating, Ventilation, Air Conditioning and Refrigeration.

I

Installer

any individual, firm, corporation, or company that either directly or through a representative is engaged in the installation, replacement, repair, or servicing of gas piping, venting systems, appliances, components, accessories, or equipment, and whose representative is either experienced or trained, or both, in such work and has complied with the requirements of the authority having jurisdiction.

Indoor Air Quality (IAQ)

This is a term which refers to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants.

M

MERV Rating

Minimum Efficiency Reporting Value, describes the size of the holes in the filter that allow air to pass through. The higher the MERV rating, the smaller the holes in the filter, and the higher the efficiency.

Micron

A unit of measure equal to one millionth of a meter, or one thousandth of a millimeter.

P

Packaged Unit

A heating and cooling system contained in one outdoor unit.

Particles

Any substances measuring less than 100 microns in diameter. It has been found that particles less than 2.5 microns are responsible for the health effects of greatest concern.

Programmable Thermostat

A thermostat with the ability to record different temperature/time settings for home heating and/or cooling equipment.

R

R-22 Refrigerant

The old standard of refrigerant, that is now being phased out. some manufacturers offer dry-charged units for those who still have R-22 compatible systems.

R-410A Refrigerant

A newer standard of refrigerant that is been used, which is a chlorine-free refrigerant that meets most environmental guidelines.

Refrigerant

A chemical that produces a cooling effect while expanding(liquid) or vaporizing(gas).

S

Scroll Compressor

A specially designed compressor that works in a circular motion, as opposed to up-and-down piston action.

Seasonal Energy Efficiency Ratio (SEER)

Seasonal Energy Efficiency Ratio, an energy efficiency rating for air conditioners. The higher the SEER, the more efficient the unit.

Split System

A heating and cooling system that includes an indoor unit, outdoor unit and a thermostat.

T

Thermostat

A unit that allows homeowners to monitor and adjust heating and cooling equipment.

Ton

Unit of measurement for determining cooling capacity. One ton equals 12,000 Btuh.

Two-Stage Operation

Provides two levels of heating or cooling output for enhanced temperature control, energy efficiency and indoor air quality.

U

Upflow

Describes an air handler or furnace that is installed in an upright position and circulates air through the side or bottom and out through the top. Typically used in basement, closet and attic installations.

V

Variable Speed Motor

A motor that operates at a wide range of speeds to precisely control the distribution of heated and cooled air throughout the home.

Ventilator

A system that exchanges stale, recirculated indoor air with fresh, filtered outside air.

W

Water heater

a household appliance consisting of a gas or electric heating unit under a tank in which water is heated and stored.

Z

Zoning system

A zoning system sections a building or a space into zones which are controlled independently of each other. This is beneficial when different areas or rooms of a building have different temperatures as well as when the desired temperatures in different rooms are different. Temperature is controlled by different thermostats.