The Most Common Air Filter Sizes

Swapping out filters on your AC system routinely will lengthen the lifespan of your AC system. Before doing so, you need to know the proper filter size for your system. When changing out the filter on your AC system, size certainly matters. Continue reading to find out how to get an accurate measurement and find the perfect sized filter for your system.

How Does Filter Size Work?

Filters are labeled with three-part dimensions. The first number is the filter’s length. The second number is the filter’s width. The third number is the filter’s depth or thickness. For example, a filter labeled as 10” X 12” X 1” is 10 inches long, 12 inches wide, and one inch thick. 

The following are the most common filter sizes:

• 10” X 20” X 1”
• 14” X 20” X 1”
• 16” X 24” X 1”
• 18” X 30” X 1”

It’s important to remember that a filter’s advertised size is slightly larger than its actual dimensions. Understanding how these two sizes correlate will help you choose the appropriately sized filter for your system.

Signs Your Filter is the Wrong Size

The wrong size HVAC filter can compromise your entire system. A filter that isn’t the right size won’t create the seal required to filter your air properly. The gaps will allow dirt, dust, and germs to bypass the filter and recirculate into the air in your home. 

The following are cues that your filter might be the wrong size:

• If your filter makes rattling noises inside your system, it indicates that the filter might be too small.
• If there’s an increase in dust inside your home, your filter is probably too small.
• If you have to force your filter into its slot, it’s probably too big.
• If the filter has bent corners, it’s probably too big when you take it out.

Your HVAC Professionals

While swapping out filters isn’t something you need an HVAC professional for, many other maintenance routines do require an HVAC professional. At Sky Air & Heat, we take pride in our work, and our technicians provide the best service possible. Contact us for a free consultation.