Technical directory · Filtration
Filter size and nominal dimensions
A printed nominal size may differ from the filter's actual dimensions by a fraction of an inch.
What to observe
Read the rack label and measure the existing media and clear opening; photograph model and airflow arrow.
A field example
A nominal 16 by 25 filter may not measure exactly those dimensions. Keep the old frame until the new product seats correctly; forcing a tight filter can deform it and leave an unintended gap elsewhere.
What the written work should say
The replacement should seat without force or gaps, and the homeowner should retain the exact product dimensions for the next purchase.
Where this task stops
A filter that merely has the same nominal numbers may still fit poorly in an unusual cabinet.