WELL BEFORE IT LOOKS LIKE THIS!!
Bill Zoller, a Chantilly, Virginia area home inspector with U.S. Inspect, shared this information about air filters. NEVER wait this long, the most commonly recommended period for filter change is every three months, but I have heard as often as once a month can be necessary depending on particular circumstances...
Over time, let your filter determine the frequency of changing...
If you want to leave Bill a note, please click on his link:
Answer: Extremely Dirty Air Filter!
A recent inspection took me to a fairly nice townhome complex, but a neglected and very unclean single family unit. What I found were grossly stained carpets, holes in the walls, missing doors, etc.
My next 'find' was this extremely dirty air filter from the forced air furnace. This home had an unfinished basement with unimpeded access to the filter, easily replaced by removing only the furnace front cover. The furnace was a 2005 manufacture, and it's possible this filter was never changed.
Incidently, the furnace was defected for 'short-cyling'. Who knows how long it had been malfunctioning, and if it had anything to do with the completely plugged air filter.
A good reason to change your filter regularly!
(Posted at U.S. Inspect blog)
Chris Smith CSSBB
Chay Realty Inc., Brokerage