Air Filter Size Helper
Not sure what size air filter your HVAC system uses? Use this quick guide to help identify the right size. Filter sizes can vary based on the return grille, filter rack, media cabinet, or how the system was installed — so always verify the size printed on your current filter or contact us before replacing it.
Important: Do not force a filter into place. Using the wrong filter size can reduce airflow, allow dust to bypass the filter, or damage your equipment. If you are unsure, send us a photo of your current filter, return grille, or equipment label and we'll help you confirm it.
Select your equipment brand
Select "Other / Not Sure" if you don't know — we'll still walk you through it.
Where is your filter located?
Your home may have one or both types of filter locations.
General Filter Tips
Always check the existing filter first
The size is printed on the cardboard frame edge of your current filter. Pull it out, read the label. That's the most reliable method.
The three numbers are L × W × D
Filter sizes are listed as length × width × depth (thickness). A "16x25x1" filter is 16 inches long, 25 inches wide, and 1 inch thick.
Nominal vs. actual size
Listed filter sizes are nominal (rounded). A "16×25×1" may actually measure 15.75×24.75×0.75. This is normal — buy the labeled size, not the measured size.
Don't use a filter that's too restrictive
High-MERV (13+) filters can restrict airflow in systems not designed for them. Confirm your system can handle the filter before upgrading.
1-inch filters need changing more often
Thin 1-inch filters clog faster. Check them monthly during heavy use seasons. Media filters (4–5 inch) can last 6–12 months.
In doubt, send us a photo
Take a photo of your current filter, your air handler label, or your return grille. We can help you identify the right size for your system.
Still not sure? Just ask us.
Take a photo of your current filter, return grille, or the label on your air handler and send it to us. We'll confirm the right size and can schedule a maintenance visit if your system is due for service.