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How Often to Change Your Air Filter (and Why It Matters)

Swap it on schedule and the whole house breathes easier.

The air filter is the cheapest, most-skipped bit of home maintenance. A clogged one strains your furnace and AC and pushes dust right back into your rooms.

A fresh filter keeps air flowing — swap it on a schedule.

How often to swap it

Check monthly; replace most 1-inch filters every 60–90 days. Go shorter if you have pets, allergies, or run the system hard in summer and winter.

Check the size on the old filter's cardboard edge before you buy.

Get the size right

The size is printed on the cardboard frame of the old one (like 20x25x1). Match it exactly — a loose filter lets air sneak past unfiltered.

HVAC air filters →

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A mid-range MERV rating is plenty for most homes — don't overpay.

Do not overpay for MERV

MERV 8–11 handles dust and most allergens for a typical home. Very high MERV can choke airflow on some systems, so higher is not always better.

Tie it to the seasons or your HVAC service so it never slips.

Set a reminder

Write the date on the new filter’s edge, or set a recurring phone reminder, so it never gets forgotten again.

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