20x20x1 Air Filters

Quick answer: 20x20x1 is the nominal size printed on the frame — the actual size is about 19.5 × 19.5 × 0.75 in. It's common in ceiling and wall return grilles. Every filter below is American-made pleated media; pick your MERV rating and pack size.

Nominal vs actual: a 20x20x1 filter measures 19.5 × 19.5 × 0.75 in so it slides into a 20x20x1 slot without jamming. If your old filter says 20x20x1, these fit.

Which MERV rating for 20x20x1?

MERV 8 handles everyday dust, lint and pollen. Step up to MERV 10–12 for pet dander and allergies, and MERV 13 or higher for smoke, bacteria and wildfire season. Carbon versions add odor control for cooking, pets and VOCs. Not sure? Read our MERV rating guide.

20x20x1 FAQ

What is a 20x20x1 air filter?

20x20x1 is the nominal (label) size. The actual size is about 19.5 × 19.5 × 0.75 in, so it fits a 20x20x1 slot with room to slide in. It's common in ceiling and wall return grilles. Ironside stocks it in every MERV rating we carry, including activated-carbon versions.

What MERV rating should I get in 20x20x1?

MERV 8 covers dust and pollen for most homes. Go MERV 10–12 for pets or allergies, MERV 13+ for smoke, bacteria and wildfire season. Higher MERV means finer filtration; change it every 90 days.

Does shipping cost more if I buy more than one pack?

No. Shipping is a flat rate and stays the same on 1, 2 or 3 packs. Stocking a year of filters in one order is the cheapest way to buy — you pay freight once instead of every time.

Ironside 20x20x1 filters are made in the USA by our manufacturing partners with electrostatic synthetic media in heavy-duty frames. Replace 1-inch filters every 90 days — more often with pets or during allergy and wildfire season. Shipping is flat-rate and stays the same whether you order 1, 2 or 3 packs, so a year's supply costs less per filter than buying one at a time. Every MERV rating we stock in 20x20x1 is below, carbon options included. Built here. Breathe better.