If you're not familiar with industry terms,
please scroll down this page to find definitions of some of the
most common terminology used when referring to heating and air
conditioning systems, or click on any of the links throughout the
site to return to this page and go directly to that definition.
AFUE% - Annual Fuel Utilization Efficiency. A measure of a
furnace's heating efficiency. The higher the AFUE%, the more
efficient the product. The government's established minimum AFUE
rating for furnaces is 78%.
Air Handler - The portion of the central air conditioning or
heat pump system that moves heated or cooled air throughout a
home's ductwork. In some systems a furnace handles this
Balance Point - An outdoor temperature, usually between 30
degrees F and 45 degrees F, at which a heat pump's output exactly
equals the heating needs of the home. Below the balance point,
supplementary electric resistance heat is needed to maintain indoor
BTU - British thermal unit. The amount of heat required to
raise the temperature of one pound of water (about one pint) by one
Evaporator Coil - The portion of a heat pump or central air
conditioning system that is located in the home and functions as
the heat transfer point for warming or cooling indoor air.
Fan Coil -
An air handler/evaporator coil combination. The evaporator coil is
built into the air handler.
Heat Pump - An air conditioner that contains a valve that
allows it to alternate between heating and cooling.
Heat Source - A body of air or liquid from which heat is
collected. With Luxaire® heat pumps the air outside the home is
used as the heat source during the heating cycle.
HSPF - Heating Seasonal Performance Factor. A measure of a
heat pump's heating efficiency. The higher the HSPF, the more
efficient the product. There is no government established minimum
HSPF rating for heat pumps.
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.
SEER - Seasonal Energy Efficiency Ratio.
A measure of an air conditioner's cooling efficiency. The higher
the SEER, the more efficient the product. The government's
established minimum SEER rating for air conditioners is 10.
Single Package - A year-round heating and air conditioning
system that has all of the components completely encased in one
unit outside the home.
Split System - A heat pump or central air conditioning
system with components located both inside and outside the home.
The most common design for home use.
Supplementary Heat - The auxiliary or emergency heat,
usually electrical resistance heat, provided at temperatures below
a heat pump's balance point.
Thermostatic Expansion Valve or TXV
- A automatic valve that feeds refrigerant (Freon) to the
evaporator coil. The amount of refrigerant fed to the coil is based
on the line temperature leaving the coil. This is the preferred
method to feed refrigerant to the coil as it is more accurate than
an orifice or flo-rator commonly used.