FurnaceMaintenance2025-10-02
How Often Should You Change a Furnace Filter?
Filter changes are the single most impactful DIY furnace task — here's the right schedule.
A clean filter protects your furnace, improves air quality and saves energy. How often to change it depends on the filter type and your home.
Typical filter schedules
1-inch fiberglass or pleated filters: every 1–3 months. 4–5 inch media filters: every 6–12 months. Change more often with pets, allergies, renovations or wildfire smoke season.
Why it matters
A clogged filter restricts airflow, causing overheating, short-cycling and limit-switch lockouts. It's the most common cause of nuisance furnace faults.
Key takeaways
- Check 1-inch filters monthly during winter
- Note the size printed on the filter frame
- Use the right MERV rating for your system
- Change filters more often during wildfire season
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