How often should I change my air filter at home?

change air filter

How often you need to replace the air filters may be on the following:

  • Air filter model
  • Overall indoor air quality
  • Quantity of pets
  • Household size
  • Air pollution levels and construction around the residence
  • Your MERV Rating

For common 1"–3" air filters, companies usually tell you to change them every 30–90 days. If someone in your family suffers from mild to moderate allergies, you could put in a better air filter or replace them even more often.

The short answer to "how often should I swap the air filter?":

If you don't have a smoker or pets in your home, and your filter is the commonly 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 brands last longer?

Some air filters are supposed to survive up to six months, while others have to be swapped each month. The larger the air filter, the longer it will last. In general, you can check the thickness of the filter rather than the brand. You also need to check at the MERV Rating.

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

While a filter with a higher MERV Rating can last longer, it can also restrict the flow of air in your home. And you will have to exchange the filter more frequently. And if you have an older system, plan to substitute the filter more regularly to preserve the quality of your filter.

How regularly do I have to switch out my air filter based on thickness?

The longevity of an air filter also relies on the thickness. A 1" filter will have to be changed out more frequently compared to a 4" filter.

  • A 1" pleated air filter must be changed out every 30-60 days.
  • A 2" pleated air filter must be replaced every 3 months.
  • A 3” pleated air filter must be exchanged every 120 days.
  • A 4" pleated air filter ought to be swapped out every 6 months.
  • A 5” or 6" pleated air filter ought to be replaced every 9-12 months.

One of the benefits of denser filters is not only do they last longer, but they also posses a better MERV Rating. This means they can do a better job of filtering out the particles inside your home. They also produce less air resistance, which can help ones HVAC system work more efficiently and limit strain on components like the blower motor.

If you want a whole-house air purifier, you will also need to replace the filters more often.

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

If you own pets, you might have to change out your air filter more often. Pet hair and dander can rapidly clog an air filter and limit its effectiveness. For each shedding dog you own, expect to replace the filter a month sooner than you would in a home lacking pets. The same goes for cats, although they usually do not shed as much as dogs. If you have a hypoallergenic or non-shedding dog or cat, you might not have to switch out your air filter as much.

Even though it's a good rule of thumb, you will need to check on the air filter more frequently to figure out if it has to be swapped out. Dogs don't shed the same amount year-round. They shed more in the spring and fall when they are blowing their coat. Inspect the air filter monthly and change it when it looks clogged.

Here are averages that can help you understand how frequently 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
  • Ordinary suburban home without pets: every 3 months
  • One dog or cat: every 60 days
  • More than one pet or if anyone has allergies: 20–45 days