20x20x5 air filter: actual size and MERV options
Last checked October 30, 2026
A 20x20x5 furnace or AC filter is a nominal 20 by 20 by 5 inch size. Nordic Pure publishes its actual size as 19.63 x 19.88 x 4.38 in.
Ratings sold in this size: MERV 8, MERV 10, MERV 12, MERV 13, MERV 14, MERV 15.
Fit is by size only. Read the size on your old filter frame or measure the slot before you order.
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Actual dimensions from filter makers
- 19.63 x 19.88 x 4.38 in, published by Nordic Pure for 20x20x5 Air Filter, MERV 12. Maker page, read October 30, 2026.
MERV options in 20x20x5
| Maker | Rating | Maker page |
|---|---|---|
| Nordic Pure | MERV 10 | 20x20x5 Air Filter, MERV 10 |
| Nordic Pure | MERV 10 | 20x20x5 Air Filter, MERV 10 P + Carbon |
| Nordic Pure | MERV 12 | 20x20x5 Air Filter, MERV 12 |
| Nordic Pure | MERV 12 | 20x20x5 Air Filter, MERV 12 P + Carbon |
| Nordic Pure | MERV 13 | 20x20x5 Air Filter, MERV 13 |
| Nordic Pure | MERV 13 | 20x20x5 Air Filter, MERV 13 + Carbon |
| Nordic Pure | MERV 14 | 20x20x5 Air Filter, MERV 14 |
| Nordic Pure | MERV 14 | 20x20x5 Air Filter, MERV 14 + Carbon |
| Nordic Pure | MERV 15 | 20x20x5 Air Filter, MERV 15 |
| Nordic Pure | MERV 15 | 20x20x5 Air Filter, MERV 15 + Carbon |
| Nordic Pure | MERV 8 | 20x20x5 Air Filter, MERV 8 |
| Nordic Pure | MERV 8 | 20x20x5 Air Filter, MERV 8 P + Carbon |
| Nordic Pure | MERV 8 | 20x20x5 Air Filter, MERV 8 Pure Carbon |
Similar sizes
Turn the system off at the thermostat before you change the filter. Arrows on the frame point toward the furnace, in the direction of airflow.
Questions
What is the actual size of a 20x20x5 filter?
Nordic Pure lists it as 19.63 x 19.88 x 4.38 in. Nominal sizes are rounded up, so the real filter is slightly smaller.
Will a 20x20x5 filter fit my furnace?
Yes if your filter slot takes a 20x20x5 filter. Fit is by size, not furnace model. Check the size printed on your old filter.
How often should I change it?
Follow your system manual and the filter maker. Many makers suggest checking a 1 inch filter monthly and replacing it about every 3 months; thicker filters last longer.