20x24x1 Air Filters
20x24x1 is larger furnaces and commercial return grilles. It is available in MERV 8, MERV 11, and MERV 13 pleated, or basic MERV 1–4 fiberglass. A 20x24x1 pleated filter typically lasts 60–90 days. The 20x24x1 label is the nominal size; the actual filter measures about 19.5 x 23.5 x 0.75 inches.
About the 20x24x1 air filter
The 20x24x1 air filter is used in larger furnaces and commercial return grilles. As with all air filters, the size is given as length x width x depth in inches. The 20x24x1 label is the nominal size; the actual filter measures about 19.5 x 23.5 x 0.75 inches.
If your system uses 20x24x1, you can choose the efficiency that fits your needs — from basic equipment protection up to MERV 13 for allergies, pets, and wildfire smoke. For higher efficiency without an airflow penalty, consider moving to a deeper 2", 4", or 5" cabinet if your system allows.
20x24x1 MERV options
| MERV | Captures | Best for |
|---|---|---|
| MERV 8 | Dust, lint, pollen | Basic protection |
| MERV 11 | Above + pet dander, fine dust | Pets, mild allergies |
| MERV 13 | Above + smoke, bacteria | Allergies, asthma, smoke |
When to replace a 20x24x1 filter
A 20x24x1 (1") filter typically lasts 60–90 days. Replace it sooner if you have pets, allergies, or during wildfire smoke season. Hold it up to light — if you can't see through the media, it's time to change it.
Frequently Asked Questions
What systems use a 20x24x1 air filter?
20x24x1 is used in larger furnaces and commercial return grilles. Check the size printed on the side of your current filter to confirm before ordering.
What is the actual size of a 20x24x1 filter?
The 20x24x1 label is the nominal size; the actual filter measures about 19.5 x 23.5 x 0.75 inches. Always order by the nominal size (20x24x1) for standard filters.
Can I get a 20x24x1 filter in MERV 13?
Yes. 20x24x1 is available in MERV 13 pleated for maximum particle capture, as well as MERV 8 and MERV 11. Custom efficiencies and frames are also available.
How often should I replace a 20x24x1 filter?
Typically every 60–90 days, and more often with pets, allergies, or during smoke season.
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Need help choosing the right filter?
Talk to our Canadian air filtration team. Call 1-888-973-3635 or request a quote.