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Saving Money by Keeping Your Furnace Filters Clean


Your home’s furnace, like any piece of machinery, needs regular maintenance to perform at its best. The most important routine maintenance you can perform on your furnace is changing or cleaning your furnace’s air filters when they get dirty. Not only can clogged or dirty air filters block air flow and cause your furnace to work harder to pump warm air throughout your house, but dirty air that gets past a filter can make its way into the fan section of the furnace and damage components.

Changing or cleaning your filters regularly will help you increase the efficiency and life expectancy of your furnace while helping you cut energy costs.

Types of Furnace Air Filters

There are a wide variety of air filters for gas, oil and electric furnaces. Many furnaces use basic panel filters or washable filters made of fiberglass, but these are the least effective at filtering particles, according to the American Lung Association. Other kinds of filters include pleated filters, high efficiency pleated filters, high efficiency particulate air (HEPA) filters and electronic air cleaners. Some filters, such as HEPA filters and electronic air cleaners, which use electrical fields to trap particles, do a great job of blocking dirt and germs, but can be a bit pricey. Ultimately, you should use a filter recommended by your furnace’s manufacturer and contact the manufacturer about the details of using other kinds of filters.

Location of Furnace Air Filters

Air filters for home furnaces — gas, oil, and electric — will typically be found along the length of the return duct, in a wall, ceiling, or even in the furnace itself. Sometimes they can be difficult to locate or hidden from view behind other equipment. Check your furnace manufacturer’s documentation for the designated filter location. If you don’t have your documentation, try going to the manufacturers’ website and downloading a copy of the documentation.

Most modern HVAC systems use return air filters right in the return air grill (the grill opening in your living space that sucks air in rather than blows it out) for easy access and maintenance. But if you have a different kind of system and are having a problem locating your furnace’s filter, start at the air handler and work your way back toward the return air grill opening.

Changing and Cleaning Furnace Air Filters

Disposable furnace filters will need to be changed every month or two during the heating season, or more often if you run your furnace a lot, smoke or have pets. For best performance, washable filters should be cleaned every two weeks, or even more frequently, by letting them soak for an hour in a tub or basin filled with a solution of one part water and one part vinegar. Washable filters should be changed out every three to six months, depending on how much you use your furnace or HVAC unit. Other kinds of filters will have their own specific maintenance instructions. Your furnace manufacturer will also likely have air filter maintenance instructions.


American Lung Association Health House, “Furnace Filters: Tips About Your Furnace Filter.”

Furnace Filter Care, “Where is My Furnace Filter?

U.S. Department of Energy, Energy Efficiency & Renewable Energy, “Furnaces and Boilers.”

2/11/2014 8:51:00 AM
in Residential 
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