Technical directory · Filtration
Filter change interval
Change timing depends on loading, runtime, occupants, pets, renovations and filter design rather than one calendar rule.
What to observe
Keep a dated photo or record of the media condition and compare it during the heating season.
A field example
After sanding or drywall work, a filter can load far sooner than the previous one did in ordinary occupancy. The event and a dated inspection photo are more informative than a blanket ninety-day promise.
What the written work should say
Set an inspection reminder and replace when loaded or according to the furnace and filter makers' instructions.
Where this task stops
Frequent clogging may signal construction dust, leaks or return problems that need their own investigation.