We do not have a furnace in our home here in the Philippines, but our house in Maryland has one. It heats the whole house on those cold autumn and winter days. To keep it running efficiently and to keep the air inside the house clean we replace the furnace filters periodically. None of us tolerate dust very well, having clean filters help keep dust out of the air.
We are not really used to the cold and I don’t intend on opening the windows to air out the house when it is cold outside. I look forward to snow and experiencing four seasons, but I also want to keep my family healthy. Changing the furnace filters will help me do that.