Common HVAC terms and their definitions


Annual Fuel Utilization Efficiency. The AFUE percentage tells you how much energy is being converted to heat. The higher the number, the greater the efficiency.

Air Handler

The portion of your heating and cooling system that forces air through your home’s ductwork.


British Thermal Units. The amount of heat it takes to raise one pound of water one degree Fahrenheit. The higher the BTU rating, the larger the heating capacity of the furnace or air conditioner.


The ability of a heating or cooling system to heat or cool a given amount of space. Heating is usually expressed in BTUs; cooling is expressed in tons.

Certified matched system

The Air Conditioning, Heating and Refrigeration Institute (AHRI) puts heating and cooling equipment through rigorous certification processes to ensure systems deliver the promised performance at certain test conditions.


The motor/pump that drives the air conditioning unit. It is responsible for pumping refrigerant throughout the system.

Condenser Coil

Part of the outdoor portion of a heating or cooling system, which releases or collects heat from the outside air.


A valve or moveable plate used in ductwork that opens and closes to control airflow. They are used to direct air to specific areas of the home.


A type of furnace that takes cool air from the top and blows warm air to the bottom.


Hollow metal pipes used to transfer air throughout your house.


Frigidaire’s designation of green heating and cooling equipment.

Electronic Air Cleaner

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

Evaporator Coil

Part of the heating or cooling system located indoors that cools and dehumidifies the air by converting liquid refrigerant into gas.

Heat Exchanger

The major part of the furnace that transfers heat into your home.

Heat Pump

A unit that handles both heating and cooling. In some climates, a heat pump may handle your heating and cooling needs more efficiently than a furnace and air conditioner.

Horizontal Flow

A type of furnace, installed on its side, which draws air from one side, heats the air and then sends it out the other side.


Heating Seasonal Performance Factor. Measures the heating efficiency of a heat pump. The higher the number, the more efficient the heat pump heats your home.


A piece of equipment that adds moisture to the air as it comes out of the furnace.


Heating, Ventilation, and Air Conditioning.


A chemical that cools air as it evaporates.


Seasonal Energy Efficiency Ratio. SEER measures a unit’s cooling efficiency. The higher the number, the greater the efficiency.

Single Package

An outdoor unit that contains both a heating and a cooling system.

Split System

Refers to an air conditioner or heat pump that is combined with indoor components, such as an evaporator coil inside and a condenser coil outside your home.


A device that monitors and controls your temperature inside your home.

Ton (of air conditioning)

A ton of air conditioning refers to capacity in relation to melting one ton of ice in 24 hours. The capacity is measured in British Thermal Units (Btu); 288,000 Btu are required to melt one ton of ice in 24 hours (or 12,000 Btu/hr). A 2-ton air conditioner has a nominal capacity of about 24,000 Btu/h.


A type of furnace that draws cool air from the bottom and blows the warmed air out the top.


A ventilator captures heating or cooling energy from stale indoor air and transfers it to fresh incoming air.


Zoning allows you to control the heating and cooling delivered to specific areas of your house for a custom solution. Zoning can increase efficiency and comfort in the area of the house you use most often.