The general recommendation is to change your furnace filter every 1 to 3 months, depending on factors like filter type, household conditions, and usage. Many sources suggest checking the filter monthly and changing it at least every three months or sooner if it looks dirty. During heavy use periods like winter or if you have pets, smokers, or allergies, you may need to replace filters more frequently. Thicker filters tend to last longer, with 1- to 2-inch filters typically needing replacement every 1 to 3 months, while thicker filters (3 to 6 inches) can last 6 to 12 months. HEPA filters might only need annual replacement. Summary:
- Check filter monthly, especially during winter or heavy use.
- Replace every 1 to 3 months for most standard filters.
- Thicker or higher-efficiency filters can last longer (6-12 months).
- More frequent changes if pets, smokers, or allergies are present.
This ensures efficient furnace operation, better indoor air quality, and longer system life.
