In 1992, the Federal Government established minimum efficiency
requirements for all heating and air conditioning equipment. If your
present HVAC equipment -- a furnace, heat pump, or air conditioning
system -- was purchased and installed before that date, it could be
highly inefficient by today's standards.
Efficiency ratings are important to understand because installing a
new unit could achieve significant energy cost reductions. And that
could save you from the higher operating expenses of some pre-1992
equipment.
AFUE% =
Furnace Efficiency. "AFUE" is a measure of a furnace's
heating efficiency. It stands for Annual
Fuel Utilization Efficiency. The higher the AFUE%, the
more efficient the product. The government's established minimum
rating for furnaces is 78%.
HSPF = Heat Pump Heating Efficiency.
It stands for Heating Seasonal
Performance Factor, or HSPF. The higher the HSPF
rating, the more efficient a heat pump is at heating your home.
There is no legislated minimum rating.
SEER = Cooling Efficiency.
"SEER" is a measure of cooling efficiency for air conditioning
products. SEER stands for Seasonal Energy
Efficiency Ratio. The higher the SEER rating number,
the more energy efficient the unit. The government's established
minimum rating for air conditioning is 13.
Basic Heating
And Air Conditioning Definitions:
Air
Handler. The portion of a 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 function.
Heat
Source. A body of air or liquid from which heat is
collected. In an air source heat pump, the air outside the house
is used as the heat source during the heating cycle.
Indoor Coil. The portion of a
heat pump or central air conditioning system that is located in
the house and functions as the heat transfer point for warming or
cooling indoor air.
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 or dispelling heat to the outside air.
Single Package. A year 'round
heating and air conditioning system that has all 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 of a building -- the most common types
installed in homes.
Supplementary Heat. The
auxiliary or emergency heat provided at temperatures below a heat
pump's balance point. It is usually electrical resistance heat.
Technical Heating And Air Conditioning Definitions:
Balance
Point. An outdoor temperature -- usually between 30°F
to 45°F -- at which a heat pump's output exactly equals the
heating needs of the house. Below the balance point, supplementary
electric resistance heat is needed to maintain indoor comfort.
British Thermal Unit (Btu).
The amount of heat required to raise the temperature of one pound
of water (about one pint) by one degree Fahrenheit.
Coefficient of Performance (COP).
A ratio calculated by dividing the total heating capacity provided
by the heat pump, including circulating fan heat but excluding
supplementary resistance heat (Btu's per hour), by the total
electrical input (watts) x 3.412. (See Heating Seasonal
Performance Factor, above.)
Energy Efficiency Ratio (EER).
A ratio calculated by dividing the cooling capacity in Btu's per
hour (Btuh) by the power input in watts at a given set of rating
conditions, expressed in Btuh per watt (Btuh/watt). (See Seasonal
Energy Efficiency Ratio, above.)
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