|Steps to take before investing in
a new furnace
|By Kamil Skawinski
To save the most dollars, you should first make your
home weather-tight and then purchase and install a properly sized
high-efficiency heating unit, says Jim Maletta, owner of North Star
Energy Consulting LLC of West Allis, Wis.
"What's most often needed is insulation and air-sealing
work done in a house to eliminate any excessive heat loss, especially
when you're dealing with an older property," says Maletta.
Add sufficient attic and wall insulation, eliminate
drafts from poorly sealed windows and doors, and seal leaky ductwork
before replacing the furnace, he says. This will greatly reduce
the load that's ultimately placed on the new heating unit.
"Then when you replace your old unit, you can
actually downsize that new unit -- meaning you can put in a smaller
furnace than the one you had before -- both saving money on the
initial cost of the replacement furnace and assuring that it will
be running at maximum efficiency, since it will not be oversized,"
says Tom Wilson, owner of Viroqua, Wis.-based Residential Energy
If you replace an inefficient furnace first and later
choose to insulate and air-seal, your new unit could end up being
oversized for your heating requirements, he says. The subsequent
short-cycling it then experiences could partially negate the savings
that you might gain from installing an otherwise high-efficiency
Electricity a factor
Your home is well-insulated and weather-tight, and you've talked
to a qualified consultant or heating contractor. You've decided
to take the plunge and buy a replacement furnace. What factors should
you consider before making the new purchase?
One is that gas-savings is only part of the equation.
"A furnace can also use a significant amount of electricity,
mostly to power the fan motor that moves air through your house,"
says Randy Novak, president of Novak
Heating and Air Conditioning, a 70-year-old company specializing
in residential and light commercial HVAC in Cedar Rapids, Iowa.
Electricity usage isn't part of the Annual
Fuel Utilization Efficiency, or AFUE, rating, so to maximize
efficiency, you need to take that into consideration, he says.
Furnaces with variable-speed direct current, or DC,
fan motors are generally more efficient than units outfitted with
standard electric, or "PSC," motors. If you intend to
run the furnace fan continuously to filter air in your home throughout
the winter, an efficient variable-speed DC motor could save you
hundreds of dollars in electricity per year. The electrical efficiency
of the furnace can be important for both heating and air conditioning
in most homes, because both rely on the electric blower motor used
by the furnace.
"But not every two-stage or variable-speed furnace
uses DC motors," says Novak. "So you have to pay attention
to product specifications when shopping."