Consider a
high-efficiency gas furnace when you're replacing that boxy metal behemoth in your basement. In conjunction with well-sealed ducts, an Energy Star furnace can help your home stay toasty warm and contribute to better indoor air quality.
Every new furnace gets slapped with an AFUE percentage measuring its efficiency. The Annual Fuel Utilization Efficiency (AFUE) rating is the percentage of fuel turned into usable heat; the higher the AFUE, the more efficient the unit. A 90 AFUE furnace loses 10 percent of its energy as exhaust, but it'll still save energy significantly compared to an old, inefficient furnace with an AFUE in the 60s. (To qualify for the current
gas or propane furnace tax credit, the
furnace must have an AFUE of 95 or higher.)
Goldilocks-style, furnace size is important. One that's too big for your home heating needs will have short cycles, so it won't be very efficient. A furnace sized just right, however, can operate more efficiently and save money. To determine the right size furnace, ask your contractor for a heat-loss, heat-gain calculation rather than a rule-of-thumb sizing estimate (they're often inaccurate). You might be able to get a smaller furnace than you had before—saving additional dough—if you've upgraded your home insulation or windows since then.
New and high-efficiency furnaces often have different venting and flue requirements. Make sure your contractor also assesses your existing flue, follows new code requirements for venting furnaces, and gets necessary permits and inspections when replacing your furnace.
1. Ready to put the fun (er, furn) in furnace? Make sure your home is well insulated first, so you can get the most out of a high-efficiency or Energy Star furnace.
2. Find a licensed heating and cooling contractor to evaluate your home. He or she can weigh in on what size furnace will be best, and other issues you should be aware of.
4. Shop online to find a high-efficiency or Energy Star furnace.
5. Investigate the
tax breaks, credits, or low interest rate loans you could qualify for by investing in an Energy Star furnace. Search online or ask your local energy company for details.
6. Read the EnergyGuide label on a furnace before buying it. This label has details on furnace features, how much energy it will use, and estimated yearly operating costs. Visit
How to Use the EnergyGuide Label for more info.
7. Arrange to have your new gas furnace delivered and installed.
Check your duct system.
Up to 35 percent of a furnace's heat could be lost due to leaky ducts or piping in the attic, according to the DOE. Even if you get an Energy Star furnace with a high AFUE, you won't get the full energy savings with leaky or disconnected ducts (AFUE ratings don't incorporate duct heat loss). Consider having your contractor repair disconnected ducts and check the entirety of your ductwork for leaks. Any leaks should be sealed with mastic-type sealant (not duct tape, oddly enough).
Insulating ducts in unheated spaces to at least R-6 can boost furnace efficiency, too.
About furnaces with two-stage burners. Consider a higher-efficiency furnace with a two-stage burner if you live in a large house—the extra cost may well be worth it. These burners allow the furnace to operate at lower burn rates using less fuel when home heating needs are low; the second burner kicks in when heating demand is higher.
About ECM motors. An electronically commutated, or ECM, blower motor in your furnace could cut the cost of running it by a factor of five. Whoa. ECM motors are much more efficient than standard motors, and if you run your furnace fan all year long for comfort or air cleaning, it's especially worth considering.
Consider a programmable thermostat. If you don't already have one, think about
installing a programmable thermostat or having your contractor install it along with your new Energy Star furnace.