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Did you know that there are 5 different ‘actual’ sizes of 20x25x5 branded filters? These sizes are not interchangeable, but we’re guaranteed to have the right replacement for your HVAC unit. Simply select one of the following from the drop down below to find the best fit for your furnace:

Confused with all the choices of 20x25x5 filters? You’re not alone. Even though these filters carry the same nominal size, they range from only 4.25” thick to over 5.25” thick. The difference in these sizes is just enough to make them unique and not interchangeable.

Unfortunately, the fact that they are not interchangeable is not a coincidence. The major HVAC brand manufacturers would prefer you to purchase their (overpriced) OEM replacements for your unit. Given there are so many different varieties, no local box store can stock them all.

At FilterBuy our mission is to change that. We have the largest selection of OEM replacements available and do our best to keep up with any new sizes that the OEM companies bring to market.

We offer a full variety of MERV ratings (MERV 8, 11, and 13) in each of our aftermarket replacements, giving the consumer the most choice possible. Ironically, even our most effective (MERV 13) replacements are generally more cost effective than the original OEM replacements.

We do our best to keep our list up to date, but if you have a part number for a 20x25x5 air filter that you don’t see listed here and would like us to add it, send it to us in our contact form and we will add it. Not only will it hopefully help you, but it provides a service to similar customer looking for the same filter in the future.

Reviews From Satisfied Customers


I am so grateful to have found a quality air filter that is just the right size!

Catie F.

Verifiedverified buyer

I was extremely pleased with the customer service that I received. I had purchased the wrong size filter and you guys went above and beyond in order to get me the right ones. You’ve got a customer for years to come.

Rigoberto M.

Verifiedverified buyer

Awesome customer service, fast delivery. I will use them whenever I need new filters and will recommend to my friends!

Shirley O.

Verifiedverified buyer