18x24x2 MERV 11 Furnace & AC Air Filter
The 18x24x2 (actual size 17.5 × 23.5 × 1.75 in) in MERV 11 — captures everything MERV 8 does plus pet dander, fine dust and smog particles. Best for homes with pets or mild allergies. Below: the true dimensions, when to change it, and how this MERV compares to the others that fit the same slot.
Same size, other MERV ratings
All fit your 18x24x2x2 slot — step up for finer filtration, down for easier airflow.
Measured your slot? Other depths
Depth must match your filter slot exactly. Same 18x24x2 face, different thickness.
Frequently asked questions
What is the actual size of a 18x24x2 air filter?
A 18x24x2 is the nominal size printed on the frame. The true measured size is about 17.5 × 23.5 × 1.75 in, cut slightly under so the filter slides into the 18x24 slot. This is standard across all brands.
What does MERV 11 filter out?
MERV 11 captures everything MERV 8 does plus pet dander, fine dust and smog particles. It's best for homes with pets or mild allergies. On the box you may see it labelled MPR ~1000–1200 (3M/Filtrete) or FPR 7 (Home Depot).
How often should I change a 18x24x2x2 filter?
Change it every 3 months. A 2" filter holds more dust and lasts longer, but still check it periodically. A clogged filter strains your blower and raises energy bills.
Will a 18x24x2x2 filter fit my furnace?
Air filters are universal by size — any furnace, AC or return grille that takes a 18x24x2x2 filter will fit this one, regardless of the HVAC brand. Just match the three numbers on your old filter's frame exactly, depth included.