How To Know What Size Air Filter To Buy


Your HVAC system will operate more effectively and stay in good condition if you replace your air filter on time. It helps to keep your Furnace Filters in good shape as well. However, if you are unsure of the size of air filter you require, you can make a mistake. Sizes of air filters might seem a little overwhelming, especially because many houses have many filters of various sizes. So choosing the right size is very crucial to ensure the best air supply in your house.

How to Know the Right Size For Your Air Filter?

You only need to glance at your current filters to determine the size of the air filters utilized in your home. There will be at least a single set of numerals on the outside frame. In the case that there are a couple sets of values, the nominal size of the filter, and not its dimensions, is what should be used while shopping for replacements. As the minimum size is the numeric set required to order new filters, you can disregard the actual size written on your filter in this assignment.

Your filter size will resemble something like this: 15 x 15 x 1a, 15 x 20 x 1, or 16 x 20 x 1. Your ruffled air filter’s size is always shown as a string of three digits, with the initial number denoting the filter’s length, the second denoting its breadth, and the third denoting its density.

What To Do When It Gets Difficult to Figure The Air Filter Size?

If you have looked everywhere around your air filter but have not been able to locate the dimensions specified anywhere, it is likely time for you to get out the measuring tape and figure out the dimensions on your own. Three measures must be taken into consideration. First is length, second is the breadth, and last is depth. Your dimensions should be in inches; however, if they are not, you can buy the “nominal size” rather than the “real size.”

The term “nominal size” refers to the measures that air filter manufacturers will use to make their filters between this and an eight and a quarter of an inch smaller than what they claim to be the actual size of the filter. The purchase of a nominal-size air filter shouldn’t pose an issue for your system, though, especially if you employ high-quality filters from recognized companies like Custom Filter Directs.

Why Is It Important to Know The Right Size Of Your Air Filter? 

Depending on the kind and effectiveness of the filter, it is recommended to change the filter every 30 to 90 days. Since indoor air may be as much as five times more contaminated than outside air, nobody likes to breathe contaminants. A good air filter is the most crucial component for your home’s air that you can purchase. Therefore, knowing the proper air filter size is crucial since your HVAC system won’t be able to provide the top-notch services you want if it doesn’t have the proper fittings.


As a last option, you should contact the manufacturer and provide them with the product code of your system so they can provide you with the measurements if you have tried all the methods above and are still unable to determine the size of your air filter. Overall, determining the size of your air filter is not difficult. However, there’s more involved than you would realize, and choosing the proper size air filter is far more crucial than we realize.