| Filter Size |
Rough Opening |
Overall Size |
Free Area |
| 12 x 12 |
13 x 13 |
14.75 x 14.75 |
30 |
| 12 x 24 |
13 x 25 |
14.75 x 26.75 |
62 |
| 12 x 36 |
13 x 37 |
14.75 x 38.75 |
95 |
| 14 x 14 |
15 x 15 |
16.75 x 16.75 |
39 |
| 14 x 20 |
15 x 21 |
16.75 x 22.75 |
59 |
| 14 x 25 |
15 x 26 |
16.75 x 27.75 |
78 |
| 14 x 30 |
15 x 31 |
16.75 x 32.75 |
93 |
| 16 x 16 |
17 x 17 |
18.75 x 18.75 |
57 |
| 16 x 20 |
17 x 21 |
18.75 x 22.75 |
68 |
| 16 x 25 |
17 x 26 |
18.75 x 27.75 |
90 |
| 18 x 18 |
19 x 19 |
20.75 x 20.75 |
70 |
| 20 x 20 |
21 x 21 |
22.75 x 22.75 |
86 |
| 20 x 25 |
21 x 26 |
22.75 x 27.75 |
114 |
| 20 x 30 |
21 x 31 |
22.75 x 32.75 |
136 |
| 24 x 12 |
25 x 13 |
26.75 x 14.75 |
61 |
| 24 x 24 |
25 x 25 |
26.75 x 26.75 |
130 |
| 24 x 36 |
25 x 37 |
26.75 x 38.75 |
199 |
| 25 x 20 |
26 x 21 |
27.75 x 22.75 |
108 |
| 30 x 20 |
31 x 21 |
32.75 x 22.75 |
131 |
