How Long Do Furnace Filters Last? An Expert's Guide

When it comes to furnace filters, it's important to know how often they need to be changed. A good rule of thumb is to replace 1-inch to 2-inch filters every three months, 4-inch filters every six months, and 5-inch filters every 12 months. For 3- and 4-inch filters, plan to replace them approximately every six to nine months. If you have filters larger than 5 or 6 inches, you'll need to change them every nine to 12 months.

For example, a one-inch oven filter should be changed every one to three months. A three- to four-inch filter can last six to nine months. If you have a five- to six-inch coarse-grained filter, it can last nine to twelve months. By ensuring that your filters are changed when needed, you can enjoy a heating and cooling system that will perform at its best.

You may also appreciate having clean air that's easy to breathe. Depending on the brand or model series of the oven, they may recommend different filter sizes for your unit. As a general rule, to keep allergy sufferers as comfortable as possible, change the oven filter every 30 to 60 days. Indoor air quality equipment, such as air purifiers and air purifiers, reduce the volume of contaminants, so the boiler filter can capture fewer particles.

In homes without this equipment, the oven filter is the only line of defense against air contaminants, so the filter fills up faster. In a large home, oven filters are changed more frequently than in homes with only one or two occupants. Thomas & Galbraith's NATE-certified heating and cooling professionals share why oven filters need to be changed. Dirty oven filters represent a disaster for heating and cooling equipment, home comfort and indoor air quality. Use a filter with a MERV rating of 12, such as the Nordic Pure Filter (available on Amazon), if your oven can handle it.

Because changing oven filters is so important, here are some strategies to help you remember to do this essential home maintenance task. The deeper the folds, the greater the surface area of the filter and the more space it has to collect airborne particles, so it may not clog as quickly as a flat filter. If their goal is to increase efficiency, they can also install a cabinet that will be attached to their oven, leaving room for improved (higher) MERV filters. Once you have located your oven filter, you must determine the type of filter that you have already installed in your unit. Oven filters should be changed every month or every year; just as there are a wide variety of filters, there is a fairly wide range in terms of how often they should be replaced. Even if no one in the house is allergic, it is advisable to change the oven filter frequently - up to every 30 days if you have several pets - so that the oven works efficiently.

When considering a filter change, you may want to look at how much shed your pet is sheltering or how many pets you have, as that can be a factor in determining how many times you'll need to check or replace the filter. In summer and winter, homeowners usually change oven filters more frequently than in fall and spring.

Ben Depauw
Ben Depauw

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