Older furnaces were not designed to be as efficient as possible. Thus, it is not uncommon for a thirty-year-old furnace to be as little as 65% efficient. Furthermore, if you have an older duct system, there is a good chance that your ducts are leaking, and leaky ducts can further decrease your system efficiency by up to 40%. Thus, your combined system efficiency could be as little as 25%. You can, however, reclaim your system efficiency by buying a new furnace and sealing your ducts.
How to Recognize a Highly Efficient Furnace
A highly efficient furnace will have two key components:
1. A Second Heat Exchanger: Your furnace burns fuel to create super-heated exhaust gases and then extracts heat from those gases with a heat exchanger. Older furnaces will have one heat exchanger which leaves some heat in the gases so that they can rise up through a vent pipe and vacate your house. Leaving heat in the gases means that your furnace will never be as efficient as it could be. A newer condensing furnace will have a second heat exchanger which will extract even more heat from the gases and help you reach optimal efficiency.
2. A Modulating Motor: If your furnace motor has only one speed, it will come on full blast anytime there is a need to heat your home. In order to get better efficiency from your furnace, you need to attune your heating to your needs. A furnace with a modulating motor can run at lower speeds to maintain the temperature in your home. Just as stop-and-go traffic is bad for a car's fuel efficiency, so is stop-and-go behavior bad for furnace efficiency. A modulating furnace acts like a car on the highway to give you improved fuel efficiency.
Sealing Your Ducts
If you have exposed ducts in your attic or crawlspace, you can buy duct mastic and a putty knife and take care of your problem on your own. All you have to do is slather a thick layer of mastic along the joints and seams in your ducts. Make sure that you turn your furnace off when you apply the mastic and leave the furnace off until it has time to dry.
If you don't have exposed ducts or are unsure if you have leaky ducts, contact an HVAC contractor, such as Action Appliance Services, and have your system looked at by a professional.
If you have an inefficient furnace, it is not the end of the world. Modern furnaces can be as much as 97% efficient. By installing a highly efficient furnace in your home, and after sealing your ducts, you can save up to $720 for every $1,000, you spend on heating your home. With savings like that, you should be able to handle the financing costs of your furnace and still save money.