Top Seller1-Inch Pleated● In stock
18×20×1Air Filter
Actual size: 17.5″ × 19.5″ × 0.75″
Fits any 18x20x1 slot or return grille. Order by the size printed on your old filter.Also sold as 20x18x1.
Fits any 18x20x1 slot or return grille. Order by the size printed on your old filter.Also sold as 20x18x1.
- Free shipping $100+
- Fit guarantee
- Picked by HVAC techs
Choose your protection level
Pack size (bigger packs save more)
18x20x1 · MERV 11 · 3-Pack$44.97$28.99
Or subscribe: $9.49/filter delivered, never think about it againMERV 11 · 3-Pack
$28.99
Common questions about 18x20x1
What is the actual size of a 18x20x1 filter?+
The nominal size printed on the frame is 18x20x1, but the filter actually measures 17.5" × 19.5" × 0.75". That undercut is intentional, it slides into your filter track without binding. Order by the nominal size printed on your old filter.
Which MERV rating should I pick for a 18x20x1?+
MERV 8 handles everyday dust. MERV 11 is our most popular, it captures pet dander and pollen. MERV 13 adds smoke, bacteria, and virus-carrier capture, and it's fine in modern systems (post-1995 blowers). When in doubt, call us, a real HVAC tech answers.
How often should I change a 18x20x1 filter?+
Every 30-90 days. Monthly if you have pets or allergies; every 2-3 months otherwise. Our subscription handles the schedule for you.
Is a 20x18x1 the same as a 18x20x1?+
Yes, 18x20x1 and 20x18x1 are the same filter; the dimensions are just written in a different order. This filter fits both.
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