How often should I change my air filter at home?

change air filter

How often you need to change your air filters can rely on the following:

  • Air filter design
  • Overall indoor air quality
  • Quantity of pets
  • Household size
  • Air pollution levels and construction near the residence
  • The MERV Rating

For basic 1"–3" air filters, companies normally instruct you to change them every 30–90 days. If you suffer from mild to moderate allergies, you could put in a better air filter or change them even more often.

The quick answer to "how often do I have to change the air filter?":

If there isn't a smoker or pets in the home, and your filter is the widely sold 1" filter with a MERV rating of 4, you should be able to wait up to 90 days prior to replacing it.

What air filter styles last longer?

Some air filters are supposed to last up to six months, while others should be replaced monthly. The larger the air filter, the longer it should last. Overall, you need to check the thickness of the filter versus the brand. You also need to check at the MERV Rating.

The MERV Rating is a scale that records from 1-20 and calculates how well an air filter will pull particles from the air. The higher the MERV Rating, the smaller the particle that could be captured by your air filter.

While a filter with a higher MERV Rating should last longer, it could also restrict the ventilation in your home. And you will have to replace the filter more frequently. And if you own an older system, plan to exchange the filter more often to extend the quality of your filter.

How frequently should I substitute my air filter based on thickness?

The longevity of an air filter also depends on the thickness. A 1" filter will have to be exchanged more often instead of a 4" filter.

  • A 1" pleated air filter ought to be changed out every 30-60 days.
  • A 2" pleated air filter must be exchanged every 90 days.
  • A 3” pleated air filter ought to be exchanged every 4 months.
  • A 4" pleated air filter ought to be swapped out every 6 months.
  • A 5” or 6" pleated air filter must be replaced every 9-12 months.

One of the perks of denser filters is not only do they live longer, but they also provide a better MERV Rating. This means they should do a better job of filtering out the particles within your home. They also create less air resistance, which can help your HVAC system work more effectively and cut down on strain on components such as the blower motor.

If you have a whole-home air purifier, you will also have to replace the filters more frequently.

How often should I replace my air filter if I have a dog or cat?

If you have pets, you might need to change out your air filter more regularly. Pet hair and dander can quickly clog an air filter and lower its effectiveness. For each shedding dog you own, expect to change out the filter a month sooner than you would with a home lacking pets. The same goes for cats, although they tend not to shed as often as dogs. If you want a hypoallergenic or non-shedding dog or cat, you might not have to change out your air filter as frequently.

Although a good rule of thumb, you might want to check the air filter more frequently to decide if it has to be replaced. Dogs don't shed the same amount all year. They shed more in the spring and fall when they are blowing their coat. Take a look at the air filter every month and change it when it looks clogged.

Here are averages that might help you know how frequently you should install a new air filter at your residence:

  • Vacation house or an individual occupant and no pets or allergies: every 6–12 months
  • Standard suburban home without pets: every 3 months
  • One dog or cat: every 2 months
  • More than one pet or if anyone has allergies: 20–45 days