What Size Air Filter Do I Need to Replace My Current One?

The easiest way to figure out what size filter to buy for your furnace is to simply remove the current filter and look at its dimensions. They are usually printed together with one of the sides of the filter.

If you live in an old house, with a non-standard sized air return frame, you can use waterproof foam tape to slightly increase the dimensions of your favorite filter or order a custom-sized air filter.

Replacing your boiler filter on time is much easier when you know what size air filter you need. There are many options for buying air filters conveniently, whether online, through your HVAC service company, or in a store.

When you buy air filters, you'll see the words “nominal size” and “actual size” together. One thing to keep in mind is that the actual size of the filter may vary slightly from the one printed on it, sometimes up to half an inch smaller for each dimension. If you need help choosing the right size filter for your boiler, contact Jerry Kelly Heating & Air Conditioning, your St. Louis area HVAC experts.

Rensa Filtration is a family of air filtration companies that manufacture and market best-in-class solutions that protect people and keep industries thriving. Keep in mind that most disposable air filters are discounted (this is an industry standard), between ¼ and ½. Air conditioning filters are available in many different sizes, so it can be overwhelming to not be sure what size filter you need. Most large retailers, such as Walmart, Target, and Home Depot, sell air filters, though with a different variety of options and brands to choose from.

If the filter were the same size as the slot in which it fits, it would be very difficult to install and remove it. If you're looking for a dealer near you that sells custom-sized air filters, you might be out of luck. As an HVAC expert, I understand how important it is to know what size air filter you need when replacing your current one. To ensure that the next filter you buy is the right size for your system, it's essential to measure the interior dimensions of the air filter inlet before making a purchase.

If your house has an old or non-standard sized air return frame, then waterproof foam tape can be used to slightly increase the dimensions of your favorite filter or order a custom-sized air filter. When shopping for an air filter online or in store, make sure to pay attention to both “nominal size” and “actual size” labels on the product packaging. The actual size of the filter may vary slightly from what is printed on it by up to half an inch for each dimension. Most disposable air filters are discounted between ¼ and ½ off their original price tag.

Air conditioning filters come in many different sizes so it can be difficult to know which one is right for your system. Most large retailers such as Walmart, Target, and Home Depot sell air filters with different varieties of options and brands available. If you're still unsure about what size air filter to buy for your system or if you're looking for a dealer near you that sells custom-sized air filters but can't seem to find one, don't worry! Contact a local HVAC service company like Jerry Kelly Heating & Air Conditioning for help choosing the right size filter for your boiler or check out Rensa Filtration's best-in-class solutions that protect people and keep industries thriving.

Simon Genz
Simon Genz

Infuriatingly humble social media practitioner. Incurable communicator. Friendly internet trailblazer. Zombie fan. Lifelong foodaholic.