When it's time for a new heating system , it makes sense to invest in high-efficiency equipment. The money you save in energy costs can pay back the price difference in just a few years.
The type of system that's best for you depends on the size, style and age of your home, as well as the type of energy available.
Finding a high-efficiency furnace
The energy efficiency of a forced-air furnace is measured by its AFUE - annual fuel utilization efficiency. This number calculates the percent of energy used that is returned to your home in the form of warm air.
For example, today's high-efficiency furnaces have an average AFUE of 93.2 - for every dollar you spend on heating energy, 93.2 percent is put back into your home as warmed air.
How it works
A standard furnace, with an AFUE of 80 to 85 percent, has only one heat exchanger to extract the warmth produced by the gas burner. As the AFUE indicates, only 80 percent of the available heat is circulated back into your home - the rest turns into water vapor that's exhausted outdoors through the flue pipe.
In a high-efficiency furnace, with an AFUE of 90 percent or higher, a secondary heat exchanger will evaporate that water vapor a second time to pull out nearly all the available heat. If you invest in a 96 AFUE furnace, only four percent of the available heat is wasted.
Forced-air furnaces manufactured 20 years ago had AFUE ratings of 60 percent or less. And if your home still has an old “gravity-flow” furnace with no blower fan, more than 70 percent of the heat can be wasted.
New furnaces will also have other energy-smart features like electronic pilot light ignitions, sealed combustion units and vent dampers.
Choosing the heating source
If you've owned your home for a few years, you're probably familiar with the volatile nature of natural gas prices - and you might be wondering if you should switch to another type of heating fuel. Even with the seasonal increases in gas prices, caused by tight supplies, a high-efficiency natural gas furnace will cost less to operate than an electric furnace.
Operating costs for fuel oil and liquid propane might be comparable to natural gas, but keep in mind that natural gas is always available with no bulky storage tanks. It's also much better for the environment, producing virtually no emissions.
Installing your new furnace
If you don't already have one, the installation of your new furnace is a great time to add a programmable thermostat. If you use it to automatically lower the temperature 10 degrees while you're working or away from home, you'll cut your heating costs by 10 percent!
And if you prefer to keep lower temperatures in rooms you don't use, check out the new zoned thermostat systems available.
Maintaining your furnace
No matter what the age of your furnace, you can improve energy efficiency by keeping it in good working order. A few simple furnace maintenance tasks will ensure you're getting the most for your energy dollar.
When was the last time you changed or cleaned your furnace filter? heating technician say more than half their service calls are caused by simple dust and dirt clogging up vital motor parts! Failing to check the filter regularly can be costly: dust and dirt can work their way into the blower and coil assemblies, reducing the furnace's operating efficiency and eventually damaging the motor. Most dealers recommended changing disposable filters once a month, or cleaning reusable filters every other month.
An annual checkup by a service technician is also a good idea - especially if you have a natural gas system. The technician will check the flues and temperature settings, examine the heat exchanger for cracks, and check the safety mechanisms. A $50-$100 annual tune-up can reduce your heating costs by five percent - and it's the best prevention against deadly carbon monoxide poisoning.
During the winter, be sure to clear snow and ice away from the intake and exhaust vents outdoors. If the vents become blocked, dangerous carbon monoxide fumes can back up into the house, and the furnace could shut down.