Ask any HVAC technician—including myself—and we’ll tell you the same thing: a clean filter is your first line of defense when it comes to efficiency and savings.

Your AC system needs airflow to function properly. When your filter gets clogged with dust, pollen, and debris, it chokes off that airflow. That makes your system work harder—cooling less effectively and using more energy to do it. Dirty filters can increase your energy consumption by up to 15%, according to the Department of Energy.

But it’s not just about energy use. Dirty filters can shorten your system’s lifespan. When airflow is restricted, components like the blower motor and evaporator coil experience extra strain. Over time, this can lead to breakdowns or expensive repairs. I’ve replaced more motors and coils due to filter neglect than I can count.

Keeping your filter clean also improves indoor air quality, which is especially important for families with allergies or respiratory issues. Less dust in your system means less dust circulating in your home.

The good news? It’s cheap and easy. Replace or clean your filter every 1 to 3 months, depending on the type and your home environment. Pets, smokers, or dusty areas may require more frequent changes.

In my years on the job, I’ve seen the same thing time and again: a $10 filter can save you hundreds in energy costs and repairs. It’s the easiest money-saving step a homeowner can take—and yet it’s often ignored.

Make it a habit. Set a reminder on your phone. Your AC system—and your wallet—will thank you.