Industry Terms

Heating and Cooling Industry (HVAC) Terms & Definitions

This page contains the most common heating and cooling industry terms and definitions. Understanding these terms will assist you with selecting the proper heating and cooling equipment for your application.

Central Air Conditioning Systems Terms:

Cooling BTU Output:
Industry standard of measuring the capacity of a system, denoting how much cooling BTU is “put out”.

Cooling Ton:
Industry standard of expressing the size of a cooling system.
1 ton = 12,000 BTU, 2 Ton = 24,000 BTU etc.

Pre-Charged System:
Hamilton Condenser, Coil and Line Sets are all pre-charged with the proper amount of refrigerant for the system to operate, once the connections are made.

Quick Connect Fittings:
Hamilton uses threaded brass fittings on the Condenser, Coil and Line Set that eliminate all soldering, brazing and charging. Keeps the system pre-charged so that once the connections are made, the system is operational.

SEER Rating:
The rating used to denote the efficiency of a system. The standard efficiency is rated at 13 and 14 SEER depending upon your geographic location, and whether it is an A/C or a heat pump system. The higher the SEER, the more the energy savings on the energy usage and subsequently, the energy bill.

Split System:
Consists of 3 components: Condenser, Evaporator Coil, and Line Set.


Central Heating Terms:

Refers to how a furnace will be used, such as upflow, downflow or horizontal.

The rating used to denote the efficiency of a furnace. Standard efficiency is 80% AFUE while high efficiency is considered 90+% AFUE or higher. The higher the AFUE, the more savings on the energy usage and subsequently, the energy bill.

“Air Conditioning Ready” Furnace:
Refers to a furnace’s compatibility with typical thermostat wiring configurations for heating and cooling. An Air conditioning ready furnace usually has a “multi-speed” blower motor, capable of handling a variety of air conditioner sizes (i.e. 2-3.5 tons).

Stands for “cubic feet per minute.” This refers to the speed of the blower motor. It takes a minimum of 400 CFM to support each ton of air conditioning.

Furnace Size:
The BTU output which matches or exceeds your home’s estimated heating cost.

Furnace Type:
The fuel source that operates or “runs the furnace”. It is either natural gas, propane (LP) gas, electric or oil.

Furnace Model:
The direction in which the heated air flows or is discharged from the furnace.

Heating BTU Output:
The total amount of heat that a furnace must “put out” or produce to properly heat a home.

Metal ‘box-like’ chamber attached to the supply air opening of a furnace. Used as the beginning of the air distribution system.

Return Air Drop:
Metal ‘box-like’ chamber attached to the return air opening of an upflow furnace. Used as the beginning of the return air system, this ductwork kit usually contains a “built-in” furnace filter rack.


HVAC Industry Certifications:

AGA Approved:
The American Gas Association® (AGA) represents 195 local energy utility companies that deliver natural gas to more than 56 million homes, businesses and industries throughout the United States. The American Gas Association advocates the interests of its energy utility members and their customers, and provides information and services promoting demand   and supply growth and operational excellence in the safe, reliable and cost-competitive delivery of natural gas.

AHRI Certification:
The Air-Conditioning Heating and Refrigeration Institute® (ARI) consists of manufacturers who voluntarily participate in independent testing to ensure that their product will perform according to published claims.

GAMA Certification:
The Gas Appliance Manufacturers Association® (GAMA), is a national trade association of manufacturers of residential, commercial and industrial appliances and equipment, components and related products. GAMA’s scope includes oil-fired and electric equipment as well as gas-fired equipment. GAMA’s members account for over 90% of U.S. sales of gas and oil-fired space heating equipment and gas, oil and electric water heaters.

UL Listed:
Underwriter’s Laboratory® (UL) is the trusted source across the globe for product compliance. Benefiting a range of customers – from manufacturers and retailers to consumers and regulating bodies – we’ve tested products for public safety for more than a century.