How often should I change my air filter at home?

change air filter

How regularly you should replace your air filters could rely on the following:

  • Air filter style
  • Total indoor air quality
  • Quantity of pets
  • Household size
  • Air pollution levels and construction near the residence
  • Your MERV Rating

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

The quick answer to "how often should I switch out the air filter?":

If you don't have a smoker or pets in your home, and the 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 changing it.

What air filter styles survive longer?

Some air filters are designed to survive up to six months, while others should be swapped monthly. The larger the air filter, the longer it will last. In general, you should look at the thickness of the filter rather than the brand. You also need to consider at the MERV Rating.

The MERV Rating is a scale that goes from 1-20 and calculates how well an air filter will remove particles from the air. The better the MERV Rating, the smaller the particle that can be caught by the air filter.

While a filter with a higher MERV Rating will last longer, it could also interfere with the ventilation in your home. And you will need to exchange the filter more regularly. And if you have an older system, plan to substitute the filter more often to conserve the quality of your filter.

How often do I need to replace my air filter based on thickness?

The longevity of an air filter also hinges on its thickness. A 1" filter will need to be changed out more often compared to a 4" filter.

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

One of the benefits of denser filters is not only do they last longer, but they also have a better MERV Rating. This means they can do a superior job of filtering out the particles within your home. They also generate less air resistance, which can help an HVAC system run more effectively and reduce wear and tear on components such as the blower motor.

If you want a whole-house air purifier, you will also need to switch out the filters more frequently.

How frequently should I exchange my air filter if I want a dog or cat?

If you have pets, you might need to switch out your air filter more frequently. Pet hair and dander can quickly clog an air filter and minimize its effectiveness. For each shedding dog you want, expect to replace the filter a month earlier than you would in a home with no pets. The same is true of cats, although they usually do not shed as often as dogs. If you want a hypoallergenic or non-shedding dog or cat, you might not have to replace your air filter as often.

Even though it's a good rule of thumb, you might want to check the air filter more regularly to decide if it should be exchanged. Dogs don't shed at the same rate all year. They shed more in the spring and fall when they are blowing their coat. Inspect the air filter each month and change it when it looks clogged.

Here are averages that can help you recognize how often you should put in a new air filter at your residence:

  • Vacation house or one occupant and no pets or allergies: every 6–12 months
  • Average suburban home without pets: every 3 months
  • One dog or cat: every 60 days
  • More than one pet or if somebody has allergies: 20–45 days