How to Determine the Correct Size Filter for Your HVAC System

The simplest solution to finding the proper size of your HVAC filter is to check your system’s Operations Manual to get the proper size to buy.

If you cannot find the manual, you might want to check online, either with the HVAC system’s manufacturer or a distributor who has posted the manual online. You can likely use your browser and put in the make and model number of the unit to find the information you need.

If for some reason, you cannot find a copy of your HVAC systems filter size, remove the existing filter and look for its dimensions. The filter’s dimensions are usually printed on the filter’s frame. The size you find printed on the filter will be slightly larger than the actual filter’s dimensions due to the need for space to insert the filter so don’t let the dimensions confuse you.

For example, let’s take a look at the dimensions of a filter that is 20” x 25” x 5”. According to the dimensions on the filter’s frame, one would assume the filter size is 20” wide x 25” long x 5” thick. Despite this, due to the need for a small amount of additional room in the compartment that holds the filter for proper insertion, the actual dimensions of the filter are: 19-7/8” x 24-7/8” x 4-3/8”.

If you are confused as to the proper size of the filter for your heating and/or air conditioning system, we invite you to consult with our team of Nordic Pure professionals to solve your questions.