How Often Should You Change Your AC Filter in Central Texas?

Quick answer: Check a standard 1-inch filter every month and change it when it looks gray and dusty, which in a Central Texas summer often means every 1 to 2 months. ENERGY STAR’s rule is simple: check it monthly and change it at least every 3 months. Thicker 4- to 5-inch media filters last longer, so follow the label and still check.

Why do Central Texas homes go through filters faster?

Because the AC here barely gets a day off. From roughly May through October the blower runs for hours a day, and every minute it runs, the filter is catching something.

Local conditions add to the load. Cedar season fills the air with pollen in winter, new construction kicks up dust in growing suburbs, and plenty of homes have a dog who sheds like it’s a job. If your air handler sits in the attic and the return side of the ductwork leaks, it can also pull attic dust straight toward the filter. Leaky ducts are a common reason one house clogs filters twice as fast as the house next door.

How can you tell when your AC filter needs changing?

Look at it. If you hold a 1-inch filter up to a light and can barely see light through it, it’s done.

• The pleats have a gray or brown coat instead of their original color.
• The filter is bowed or sucked in toward the unit.
• Dust is collecting on the supply registers or around the return grille.
• You can’t remember the last change. Write the date on the frame with a marker next time.

Does filter thickness change how often you replace it?

Yes. A thin 1-inch filter has little surface area, so it loads up quickly and usually needs changing every 1 to 3 months. A 4- or 5-inch media filter in a dedicated cabinet has far more pleated surface, and many are rated to last several months or longer. The manufacturer’s label is the guide, but check it anyway during a dusty summer.

Washable filters need rinsing on the maker’s schedule, and they must dry completely before going back in. A damp filter in a humid attic is an invitation you don’t want to send.

Does a higher MERV filter need changing more often?

Often, yes. A higher MERV filter catches more fine particles, so it can fill up faster, and it starts out with more resistance to airflow. That’s why a MERV 13 filter jammed into a 1-inch slot on a basic system can cause more trouble than it solves. Our guide to MERV ratings walks through which rating fits which kind of system.

What happens if you leave a dirty filter in too long?

Airflow drops, and the rest of the system pays for it. With too little air moving across the indoor coil, the coil can get cold enough to freeze, and when that ice melts it can overwhelm the drain. See why an AC freezes up or leaks water for how that chain plays out.

A clogged filter also lets more dust slip around its edges and settle on the coil, where it’s much harder to clean than a filter is to replace.

Where is your AC filter?

In many Austin-area homes it’s behind a return grille in a hallway ceiling or wall. In others it slides into a slot at the air handler in the attic, a closet or the garage. Some homes have more than one return, each with its own filter.

If you find a filter at the grille and another at the unit, ask your technician if you need both. Two filters in a row add resistance. When you slide a new one in, the arrow on the frame points toward the air handler, in the direction the air flows.

Related guides: What Are MERV Ratings, and How Do They Affect IAQ?, What’s Included in an HVAC Tune-Up? and Leaky Ducts: How They Pull Attic Air and Dust Into Your Home.

About Gold Eagle Services: This guide comes from the team at Gold Eagle Services, a family-run Austin HVAC, indoor air quality and mold remediation company founded in 2017. We’re licensed (TACLA119235 and RCO1783), insured and bonded, and we serve homes across the greater Austin area.

Need help with this in your home? Learn about our indoor air quality solutions, or call 512-489-4653 to schedule a visit.

Related Gold Eagle service: Home maintenance plan