Your HVAC air filter may seem like a small part of your heating and cooling system, but it has a big job. It traps dust, pollen, pet hair, and other airborne particles before they reach your equipment or circulate through your home. When the filter becomes dirty, airflow drops, your system has to work harder, and your energy bills can increase. So, how often to change an HVAC filter? For most homes, replacing the filter every 1 to 3 months is a good rule of thumb. However, the right schedule depends on your home, your filter type, and your lifestyle. Frequency to Change an HVAC Filter There isn’t a single answer that works for everyone. Here are some general guidelines: Every 30–60 days: Homes with pets, allergies, or high dust levels. Every 60–90 days: Average households with standard HVAC use. Every 6–12 months: Some high-capacity media filters, if recommended by the manufacturer. If you’re unsure, inspect the filter once a month. If it looks gray, clogged, or covered in dust, ...