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21.75×23.5625×1 air filter
Fits any system that takes a 21.75×23.5625×1 filter. Actual size 21.5 × 23.313 × 0.75 inches, cut to within 1/16 inch and measured by camera before it ships. Made in New Albany, Indiana. Free shipping; orders placed by 2 pm Eastern ship the same day.
Grades and prices
| Grade | What it catches | Price per filter |
|---|---|---|
| Everyday (MERV 8) | Dust, lint and pollen. The right pick for most homes. | 4-pack $10.50 each, 6-pack $8.01 each, 12-pack $7.53 each |
| Allergy (MERV 11) | Adds pet dander and mold spores. For pets and allergy season. | 4-pack $12.59 each, 6-pack $9.61 each, 12-pack $9.04 each |
| Allergy + Smoke (MERV 13) | Adds smoke, smog and fine particles. For wildfire season and asthma. | 4-pack $13.12 each, 6-pack $10.01 each, 12-pack $9.41 each |
Subscribe and save 10%. Choose When you need it, timed to your local weather, air quality and household and billed per box, or Every few months, a box every 3, 6 or 12 months. Skip, change or cancel anytime.
Questions
Is 21.75×23.5625×1 the real size?
Not quite, and that's normal. 21.75×23.5625×1 is the size on the label. The filter itself measures 21.5 × 23.313 × 0.75 in, a little smaller so it slides into the slot. We cut ours to within 1/16 inch of that.
Which grade do I need?
Most homes do great with Everyday (MERV 8). If you have pets or someone with allergies, go Allergy (MERV 11). If wildfire smoke reaches you or someone at home has asthma, Allergy + Smoke (MERV 13) also catches smoke and smog. All three fit the same slot.
How often should I change it?
When it starts catching less and slowing your air. The rule of thumb is every 3 months for Everyday and Allergy, and about every 10 weeks for Allergy + Smoke. That assumes every month is average. Heating and AC season, pollen, pets and smoke fill a filter faster, so "When you need it" times each swap to your home's weather and household instead of the calendar.
What if it doesn't fit?
Tell us within 30 days and we'll send a new one free, and you keep the first. That's our fit guarantee.