Airflow Volume:  Measured in cubic feet per minute (cfm), this is the amount of air circulated in a space.

ASME:  American Society of Mechanical Engineers.

BTU:  A British Thermal Unit is a measurement of the amount of heat required to raise or lower the temperature of one pound of water one degree Fahrenheit.

BTU/h:  British Thermal Units per hour

Burner:  The device that facilitates the combustion of air and gas.

CSA:  Canadian Standards Association.

Flue:  A vent that removes the byproducts of combustion from a furnace.

Heat Exchanger:  A device through which heat is transferred to a cold or warm area or surface.

Heating Coil:  A coil that acts as a heat source for a heating system.

Heat Loss:  The amount of heat lost or subtracted from a designated area.

Heat Pump:  A device used for either the heating or cooling of a space by transferring heat between two reservoirs.

PSI:  A pound per square inch is a unit of pressure resulting from the force of one pound-force applied to an area of one square inch.

Thermostat:  A wall mounted device that monitors and controls the output of an HVAC system.