Chapter 08Home & Car

How often should I change my HVAC filter?

Every 60–90 days for a standard 1-inch filter, every 6–12 months for a 4-inch pleated filter. Pets, allergies, and dust push you toward the shorter end.

Follow-up questions

MERV rating — what should I buy?

MERV 8–11 for most homes. Higher restricts airflow enough to strain the blower unless the system is sized for it.

Does a dirty filter really matter?

Yes — it drops efficiency, freezes coils, and shortens system life. Cheapest maintenance you'll ever do.

Do washable filters work?

They're low MERV. Fine for large debris, not great for fine particulates or allergies.

Signs my filter needs changing?

Weaker airflow, dusty vents, longer runtimes, or a visibly gray filter.

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