Best Way to Find Your AC Filter Size

The filter is an essential component for the optimum efficiency and performance of an air conditioning system. Not only do you need to install the correct type of AC filter, but you also need to ensure you are using the correct size. Using an air filter that is too big or too small can make your home uncomfortably humid or cause damage to the components of the HVAC system. With so many AC filters on the market, it can be challenging to pick the right one. Here is a quick guide on finding your AC filter size. 

The Importance of Using a Correct Filter Size 

AC filters clean the indoor air by capturing airborne particles. This benefits both your health and the HVAC system. When choosing an AC filter, it is important to pick the correct size.

When an AC filter fits smoothly in its compartment, it allows adequate airflow into the unit and captures contaminants in the air. However, if the filter is not the right size, either it won’t fit or it won’t allow for air to pass through the gaps on the side. The problems an improperly-sized air filter can cause include increased utility bills, inadequate cooling, and system overheating.

How to Find the Right AC Filter Size? 

Most manufacturers print nominal size dimensions on their AC filters. Nominal sizes generally do not include the undercut and only indicate the rounded dimensions of an AC filter. However, the actual sizes of AC filters are not rounded and typically include the undercut.  

Most AC filters have their nominal sizes printed on the sides, so that should be the first place you check when determining the filter size you need. If you cannot find dimensions printed on the filter, you can measure the existing filter yourself.

Typically, filter sizes are listed in length, width, and depth. These are the measurements you need to find the right filter. For most AC filters, the length and width dimensions can be interchangeable. However, in conventional AC filters, length can be the shorter dimension, and width can be the largest dimension of the filter. 

You shouldn’t cut the air filter yourself because cutting an AC filter requires precision, and even the slightest error can result in the air filter losing its structural integrity and efficiency. While cutting an AC filter may seem straightforward, regular filters are not designed to be cut. If you’re having difficulties finding the right size, you should purchase a cut-to-fit filter. 

Cut to Fit Filters

If you cannot find the correct AC filter size or have a custom-shaped vent, a cut-to-fit AC filter can be the right option. For example, if you have a circular or rectangular-shaped vent of an irregular size, you can get a cut-to-fit AC filter for a perfect fit. Charcoal or carbon cut-to-fit AC filters can also be used for enhanced filtration.