Heating bills vary each winter, prompting homeowners
to consider replacing inefficient furnaces. Sales at some showrooms
increased by about 25 percent in the last quarter of 2005 over the
previous year, and many HVAC (heating, ventilating and air conditioning)
contractors expect an even greater boost in furnace sales as more
consumers reel from heating bill shock-and-awe.
But then they'll face the shocking sticker price of a new furnace.
Depending on the state of existing ductwork, gas piping and electrical
wiring, the average cost of a new high-efficiency furnace with installation
will run between $2,500 and $3,000.
So just how much can you typically save by replacing
an old, inefficient furnace with a properly sized modern unit? It
depends on how efficient the new furnace is and how inefficient
the old one was. Annual
Fuel Utilization Efficiency, or AFUE, ratings will tell you
how much energy is being converted to heat. For example, an AFUE
of 80 means that 80 percent of the fuel used by the furnace warms
your home, while the other 20 percent escapes as exhaust with combustion
Older gas furnaces that utilize pilot lights have
estimated AFUE ratings of 55 percent to 65 percent, so both your
immediate and long-term savings could be significant if you replace
such an inefficient unit with a modern 95 percent AFUE two-stage
closed-combustion gas-fired model. Today's highest efficiency units
now have an AFUE of 96.6 percent.
To determine the approximate AFUE rating of your furnace,
consult the table below, compiled by the U.S. Department of Energy.
||Typical AFUE ratings for different types
of furnaces and boilers
(To see how much you can save with a new system versus
an old one, see the table titled, "Dollar
savings per $100 of annual fuel cost.")
How old is too old?
A typical heating system will last around 25 years (boilers can
last twice as long), but only a qualified technician will be able
to determine if there are any urgent issues with a furnace in the
15-plus year age range.
"From the perspective of the average consumer
... it's hard for them to determine whether or not their gas furnace
is showing signs that it's going to fail, because there aren't really
going to be many external signs for them to look for," says
Frank Stanonik, chief technical adviser of Valtorc Valves. "But if they know
that the unit is 20 years old or older ... the fact is that they
are already on the far side of its average-life curve."
Stanonik says that consumers who replace vintage units
get trade-offs of increased efficiency, reliability and peace of
mind that they won't face expensive repairs or suddenly find themselves
without heat on the coldest day of the year.