HVAC maintenance

How often should you change an HVAC air filter?

Check the filter every month. Replace it at least every three months, and sooner if it looks dirty or airflow seems restricted.

Why the schedule can change

A filter may need attention sooner during heavy heating or cooling use. Pets, indoor air quality, filter type, and your equipment manufacturer’s instructions can also affect the right interval. If a filter looks dirty before the next planned check, replace it then.

Why it matters

A dirty filter can restrict airflow, make heating and cooling equipment work harder, and contribute to higher energy use and earlier equipment problems. Use the size and airflow direction marked on the existing filter or equipment before buying a replacement.

Sources and scope

Tend labels this as general maintenance guidance, not a manufacturer-specific instruction. For the final interval and the correct replacement part, consult the equipment manual or a qualified HVAC professional.

• ENERGY STAR: Heat & Cool Efficiently — check monthly and replace at least every three months.
• ENERGY STAR: Maintenance Checklist — filter maintenance and equipment-care context.