Robert Gammon wrote:

My BODY tells me when it is time to change the furnace filter. It not
fear,its chest congestion I am not aware of how long it has been since
I changed the furnace filter, until I start having fluid build in my
lungs, I have a persistent lump of mucus in my throat that will not
clear. I cough from time to time, and I may sneeze a bit. When these
symptoms become recognizable, I go look at the date on the furnace
filter and say "WOW, has it been really THAT long?? Look at that thick
layer of dust." This is usually 2-3 months with most pleated filters,
but seasonal pollens and molds can accelerate the filter change cycle.

How strange. Most bodies would say "Hey, it's too cold in here!!!"
as the filter clogs and furnace airflow slows, even though clogged
filters filters better.

Nick