How often should you replace a furnace air filter in a large home?

Furnace air filters in a large home should be replaced about every three months. Individuals with larger homes may need to replace filters less often because the air has more room to circulate, thus reducing the amount of lint and dust that attaches to furnace air filters.

Factors such as the efficiency of the furnace, the health of the residents and the amounts of dust or pollen in the region may affect the frequency in which the filters need to be changed. Homes with pets may need to replace furnace air filters more frequently than every three months, as pet hair can clog the filters.