I always knew about filters for air conditioners but only recently became aware that even a certain type of heater or chimney requires a furnace filter. To be honest, we have not cleaned our filter for close to four years now. I know, it is bad and probably makes the system less efficient in emitting cool or warm air. It should be DH’s duty to clean them since they are located on the ceiling. I would not mind climbing onto a ladder and get them cleaned but maybe someday.

Meanwhile, I still need to clean the kitchen hood filter, have only been wiping it the past three years.