Changing the filter is an important AC maintenance task. Once the screen is clogged, it can't trap dust and other particles that flow into the system. Instead, they will recirculate in your home, clog the blower fan, and collect on the evaporator coil. The coil won't be able to complete the cooling process by absorbing heat in the air. Equipment will work harder and drain more energy to operate correctly. To avoid poor indoor air quality and high energy bills, here is a guide to how often you should change the AC filter.

How to Determine the Frequency the AC Filter Should be Changed

Numerous factors dictate how often you should replace the AC filter. As a standard rule, strive to change the filter once a month or once every two months. If any house occupants have allergies, consider replacing the screen before the 30-day mark. 

How many pets you have and the breeds matter, too. If you only have one dog, for instance, and it is a hypoallergenic breed—meaning it doesn't shed much fur and dander—the filter won't become clogged quickly and can be changed every 60 days or so. 

AC maintenance

If you have multiple animals that experience frequent shedding, you'll need to change the filter every few weeks to combat the amount of dander and fur sucked into the system through return air ducts. If you live alone with no pets, the filter will remain relatively clean, which means you could go six to 12 months before the need for replacement. 

How to Replace the Old Filter

Although you should reach out to professionals to clean evaporator coils and tend to other complex AC maintenance tasks, changing the filter is relatively easy to do on your own. First, locate the filter, which could be in the return register behind a grate on an interior wall or ceiling. Remove the grate to access the filter. 

If not in the return register, the screen could be housed in the system's air handler in the basement, attic, closet, or crawlspace. The filter is likely in a slot close to where the blower fan and return air duct meet or on the back of the air handler behind the service door. 

Write down the numbers on the old filter's frame. These are the dimensions you'll need to find an appropriate pleated or fiberglass replacement. After installing the new screen, put the grate back on the return register or remember to close the air handler's service door.  


For AC maintenance to maximize the efficiency of your investment, contact the crew at Ecology Air Innovations in Elverta, CA. Since 2015, the professionals have been repairing and installing gas, propane, and electric HVAC equipment for homeowners in the Greater Sacramento area. The HVAC repair technicians will provide a lifetime workmanship guarantee for as long as you own your residence. Visit the air conditioning company online for special offers and read client reviews on Yelp. Call (916) 640-9464 for a service estimate.