Most air filter manufacturers recommend replacing a standard home filter (1-3 inches thick) every 30-60 days. While this is a great rule to follow in general, not every home is the same. Your home likely even varies from other homes in the neighborhood when it comes to how often you should be replacing your filter.

Different factors such as type of filter, pets, and how many people are living in a home all have a direct affect on the life span of a filter. Learn how and why this is by reading below.

Type of Air Filter

To the average homeowner, an air filter is just an air filter. But as a professional AC repairman will tell you, the specific type of filter you have affects greatly how frequently it needs to be replaced. There are several types of air filters that are made using various materials and which wear out in different ways. Three of the most common include:

• Fiberglass panel filters – the cheapest filter option that traps large dust particles. However, they need to be replaced often.

• Media filters – the most cost effective and reliable filter option for HVAC technicians. Uses multiple layers of fiber to stop air contaminates without blocking air flow.

• HEPA filters – High Efficiency Particulate Air filters are over 99% efficient at removing dust, allergens, pet dander, and other air contaminants. Great for people with allergies or asthma.

 Needs of Residents Living in Home

The occupants of your home also have an impact on how often you should be replacing your AC filter. For instance, if someone suffers from severe allergies, even if you install a HEPA filter, you will need to replace it regularly to prevent allergens from getting in.

Even the number of people living in your home has an affect on a filter’s lifespan. Single-occupant homes can get away with only replacing a filter every 6-12 months, whereas the average suburban home should get a new filter every 3 months at least.

 Pets, Pets, Pets…

 Although your home may be incomplete without your furry companion, pets are one of the single most significant contributors to clogging air filters. Their hair and dander get sucked into your home’s vents and must be sifted out from the clean air by your filter. Homeowners who have at least one pet should be replacing their AC filter every 1-2 months.

These factors and others—such as the air pollution in and around the home—mean that the best way to tell when it’s time replace your AC filter is not by reading the manufacturer’s recommendations, but by checking your filter every couple of weeks. Then, once you determine the rhythm of your AC unit, you can make sure it gets the proper maintenance so your family breathes clean air for years to come.