Reference guide for standard return vent filters. Remember: actual dimensions are always smaller than nominal size.
Nominal size is the rounded size used for ordering (e.g., 20x25x1). Actual size is the true measurement (e.g., 19.5 x 24.5 x 0.75). Always measure your current filter or filter slot to verify fit.
| Nominal Size | Actual Dimensions | Common Uses | |
|---|---|---|---|
| 10x10x1 | 9.5 x 9.5 x 0.75 | Small window AC units, Mini-split systems | Buy |
| 10x20x1 | 9.5 x 19.5 x 0.75 | Smaller return vents, Wall-mounted returns | Buy |
| 10x24x1 | 9.5 x 23.5 x 0.75 | Narrow return grilles, Specialty installations | Buy |
| 12x12x1 | 11.75 x 11.75 x 0.75 | Small square return vents, Window AC units | Buy |
| 12x16x1 | 11.5 x 15.5 x 0.75 | Small return grilles, Compact HVAC systems | Buy |
| 12x18x1 | 11.5 x 17.5 x 0.75 | Small return vents, Compact residential systems | Buy |
| 12x20x1 | 11.5 x 19.5 x 0.75 | Small return grilles, Older residential systems | Buy |
| 12x24x1 | 11.5 x 23.5 x 0.75 | Standard return grilles, Residential furnaces | Buy |
| 12x30x1 | 11.5 x 29.5 x 0.75 | Long narrow return vents, Specialty installations | Buy |
| 12x36x1 | 11.5 x 35.5 x 0.75 | Extra-long return vents, Commercial-residential crossover | Buy |
| 14x14x1 | 13.5 x 13.5 x 0.75 | Square return vents, Smaller residential systems | Buy |
| 14x18x1 | 13.5 x 17.5 x 0.75 | Small residential returns, Compact HVAC systems | Buy |
| 14x20x1 | 13.5 x 19.5 x 0.75 | Standard return vents, Residential furnaces | Buy |
| 14x24x1 | 13.375 x 23.375 x 0.75 | Standard return grilles, Residential HVAC systems | Buy |
| 14x25x1 | 13.5 x 24.5 x 0.75 | Standard return vents, Residential furnaces | Buy |
| 14x30x1 | 13.5 x 29.5 x 0.75 | Long return grilles, Larger residential systems | Buy |
| 15x20x1 | 14.5 x 19.5 x 0.75 | Standard return vents, Some older residential systems | Buy |
| 16x16x1 | 15.5 x 15.5 x 0.75 | Square return vents, Smaller residential systems | Buy |
| 16x20x1 | 15.5 x 19.5 x 0.75 | Standard return vents, Condos | Buy |
| 16x24x1 | 15.5 x 23.5 x 0.75 | Standard return grilles, Residential furnaces | Buy |
| 16x25x1 | 15.5 x 24.5 x 0.75 | Standard return vents, Most common residential furnaces | Buy |
| 16x30x1 | 15.5 x 29.5 x 0.75 | Long return grilles, Larger residential systems | Buy |
| 18x18x1 | 17.5 x 17.5 x 0.75 | Square return vents, Mid-size residential systems | Buy |
| 18x20x1 | 17.5 x 19.5 x 0.75 | Standard return vents, Residential furnaces | Buy |
| 18x24x1 | 17.5 x 23.5 x 0.75 | Standard return grilles, Residential HVAC systems | Buy |
| 18x25x1 | 17.5 x 24.5 x 0.75 | Standard return vents, Residential furnaces | Buy |
| 18x30x1 | 17.5 x 29.5 x 0.75 | Long return grilles, Larger residential systems | Buy |
| 20x20x1 | 19.5 x 19.5 x 0.75 | Square return vents, Older homes | Buy |
| 20x24x1 | 19.5 x 23.5 x 0.75 | Standard return vents, Residential furnaces | Buy |
| 20x25x1 | 19.5 x 24.5 x 0.75 | Standard return vents, Larger residential furnaces | Buy |
| 20x30x1 | 19.5 x 29.5 x 0.75 | Large return vents, Bigger residential systems | Buy |
| 24x24x1 | 23.5 x 23.5 x 0.75 | Large square returns, Commercial-residential crossover | Buy |
| 24x30x1 | 23.5 x 29.5 x 0.75 | Large return vents, Commercial-residential | Buy |
| 25x25x1 | 24.5 x 24.5 x 0.75 | Large square returns, Commercial applications | Buy |
| 30x36x1 | 29.5 x 35.5 x 0.75 | Large commercial returns, Industrial HVAC | Buy |
| Nominal Size | Actual Dimensions | Common Uses | |
|---|---|---|---|
| 10x20x2 | 9.5 x 19.5 x 1.75 | Compact systems with 2-inch slots, Higher capacity needs | Buy |
| 12x12x2 | 11.5 x 11.5 x 1.75 | Small 2-inch slots, Compact systems | Buy |
| 12x20x2 | 11.5 x 19.5 x 1.75 | 2-inch filter racks, Compact residential systems | Buy |
| 12x24x2 | 11.375 x 23.375 x 1.75 | Standard 2-inch filter racks, Residential furnaces with 2-inch slots | Buy |
| 14x20x2 | 13.375 x 19.375 x 1.75 | 2-inch filter racks, Residential systems | Buy |
| 14x25x2 | 13.375 x 24.375 x 1.75 | 2-inch filter racks, Residential furnaces | Buy |
| 16x20x2 | 15.5 x 19.5 x 1.75 | Standard 2-inch filter racks, Residential furnaces | Buy |
| 16x25x2 | 15.5 x 24.5 x 1.75 | Standard 2-inch filter racks, Residential furnaces | Buy |
| 18x25x2 | 17.5 x 24.5 x 1.75 | 2-inch filter racks, Residential systems | Buy |
| 20x20x2 | 19.5 x 19.5 x 1.75 | Square 2-inch filter racks, Residential furnaces | Buy |
| 20x24x2 | 19.5 x 23.5 x 1.75 | Standard 2-inch filter racks, Residential furnaces | Buy |
| 20x25x2 | 19.5 x 24.5 x 1.75 | Standard 2-inch filter racks, Larger residential furnaces | Buy |
| 24x24x2 | 23.5 x 23.5 x 1.75 | Large square 2-inch slots, Commercial-residential crossover | Buy |
| 25x25x2 | 24.5 x 24.5 x 1.75 | Large square 2-inch slots, Commercial applications | Buy |
| 25x28x2 | 24.5 x 27.5 x 1.75 | Specialty installations, Larger systems | Buy |
| 30x36x2 | 29.5 x 35.5 x 1.75 | Commercial HVAC, Large residential systems | Buy |
| Nominal Size | Actual Dimensions | Common Uses | |
|---|---|---|---|
| 12x24x4 | 11.375 x 23.375 x 3.625 | Media filter cabinets, Whole-house filtration | Buy |
| 14x25x4 | 13.5 x 24.5 x 3.75 | Media filter cabinets, Residential whole-house filtration | Buy |
| 16x20x4 | 15.5 x 19.5 x 3.75 | Media filter cabinets, Honeywell F100 systems | Buy |
| 16x24x4 | 15.5 x 23.5 x 3.75 | Media filter cabinets, Residential whole-house systems | Buy |
| 16x25x4 | 15.5 x 24.5 x 3.75 | Media filter cabinets, Honeywell FC100A1029 | Buy |
| 17x22x4 | 16.5 x 21.5 x 3.75 | Specialty media cabinets, Some Carrier/Bryant systems | Buy |
| 18x25x4 | 17.5 x 24.5 x 3.75 | Media filter cabinets, Mid-size whole-house systems | Buy |
| 19x20x4 | 18.5 x 19.5 x 3.75 | Specialty media cabinets, Specific manufacturer systems | Buy |
| 20x20x4 | 19.5 x 19.5 x 3.75 | Media filter cabinets, Square format whole-house systems | Buy |
| 20x24x4 | 19.5 x 23.5 x 3.75 | Media filter cabinets, Whole-house filtration | Buy |
| 20x25x4 | 19.5 x 24.5 x 3.75 | Media filter cabinets, Honeywell FC100A1037 | Buy |
| 23.5x23.5x4 | 23.38 x 23.38 x 3.75 | Large media cabinets, Commercial-residential crossover | Buy |
| 24x24x4 | 23.5 x 23.5 x 3.75 | Large media cabinets, Light commercial | Buy |
| 25x25x4 | 24.5 x 24.5 x 3.75 | Large media cabinets, Commercial HVAC | Buy |
| 30x30x4 | 29.5 x 29.5 x 3.75 | Commercial HVAC systems, Industrial applications | Buy |
| Nominal Size | Actual Dimensions | Common Uses | |
|---|---|---|---|
| 16x25x5 | 15.88 x 24.88 x 4.38 | Lennox Healthy Climate cabinets, Honeywell F200E | Buy |
| 16x25x5 | 15.63 x 24.13 x 4.88 | Honeywell media cabinets, FC100A systems | Buy |
| 16x25x5 | 15.38 x 25.5 x 5.25 | Trion Air Bear Supreme, Some Lennox BMAC models | Buy |
| 20x20x5 | 19.75 x 19.75 x 4.38 | Square media cabinets, Field Controls MAC | Buy |
| 20x25x5 | 19.88 x 24.88 x 4.38 | Lennox Healthy Climate cabinets, Honeywell F200E | Buy |
| 20x25x5 | 19.75 x 24.75 x 4.88 | Honeywell media cabinets, Trion Air Bear | Buy |
| 20x26x5 | 19.75 x 25.75 x 4.88 | AprilAire 2400 media cabinets, Specialty whole-house systems | Buy |
| 24x24x5 | 23.75 x 23.75 x 4.38 | Large square media cabinets, Commercial-residential crossover | Buy |