A furnace draws air from the house into a ductwork system, taking it to an area where it is warmed before being delivered back to living spaces. This continuous operation will keep your home toasty through the winter months. The least efficient furnace today is 80% efficient compared to the furnaces of the past which were around 50% efficient.
Forced air furnaces are designed to burn
natural gas or propane to heat yourhome. Waste products
are then vented to the outside and carrying some
of yourheat with them. The heat retained to heat
your home is the Annual Fuel UtilizationEfficiency
Simply stated, it's the percent of heat retained
to heat yourhome. The higher the percentage,
the lower your heating cost, not to mention, less electricity
to run the blower in the furnace.
Furnaces today are
rated from 80% to 94%+ A.F.U.E. compared to the 60%and
less from years ago. The furnaces today have electronic
ignition instead of thestanding pilot light from
the past. The higher A.F.U.E. rated furnaces have
variablespeed blowers and some have two-stages of
speed furnaces operate at a lower, more efficient
speed than conventional
furnaces. This eliminates short-cycling, the frequent
starting andstopping common to many conventional
furnaces. The two-stage gas valve worksefficiently
with the variable speed blower by providing only
as much fuel as eachstage requires. It operates quietly,
particularly during the first stage or low heat operation.
During continuous fan operation, the blower operates
at 50 percent ofairflow, so sound is minimized.
Most brands of equipment require a variable
speed furnace in order to achievethe higher s.e.e.r.
levels of air conditioning.Just remember the higher
the A.F.U.E. the lower your gas bill will be in the
If your furnace is 10 years old or more,
it's probably in the 60 - 70% AFUE range. That means you're wasting 30 to 40 cents out
of every dollar your spending onheat. Replacing a
60% AFUE furnace with a new 92% AFUE, you can trim
up to35% off your heating bill.
The new furnace designs will recover heat
that would normally go up the flue pipe. Some of the new 90%+ efficient furnaces
will actually squeak moisture outout of the air to
form condensation which is removed through the drain