How Often Should I Replace My AC Filter?

The generic advice is "every 90 days," and that's a fine starting point — but it's not actually the right answer for every home. A clogged filter is one of the most common, most preventable causes of reduced airflow, frozen coils, and a system working harder than it needs to, so getting the schedule right matters more than the generic answer suggests.

What actually changes the schedule

• Filter type: basic fiberglass filters need changing monthly; pleated filters often last 60-90 days; high-efficiency filters vary by manufacturer.
• Pets: shedding pets mean more airborne debris, which can cut the interval in half.
• Household size and dust: more people and more activity means more dust circulating.
• Renovation or construction nearby: dust from any nearby work clogs filters much faster than normal.
• Running the system constantly: a system that runs nonstop (common in Florida summers) moves more air through the filter than one that cycles on and off gently.

A more practical approach than a fixed date

Instead of relying purely on a calendar, check the filter visually once a month for the first few months in your home. Hold it up to a light — if you can't see light passing through it clearly, it's time to replace it regardless of what the calendar says. Once you've done this a few times, you'll have a real sense of your specific home's actual interval, which might be shorter or longer than the generic 90-day rule.

What happens if you don't

A severely clogged filter restricts airflow across the indoor coil, which can cause the coil to freeze — the same problem covered in our AC freezing article. It also forces the blower motor to work harder to push air through the restriction, which shortens its lifespan and increases your energy bill in the process.

If you're not sure what filter type or size your system takes, or you'd rather have it checked as part of a routine visit instead of tracking it yourself, that's exactly what our maintenance plans are built around — one less thing to remember.