How often should I change my air filter at home?

change air filter

How frequently you need to change the air filters might depend on the following:

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

For standard 1"–3" air filters, companies typically tell you to change them every 30–90 days. If you suffer from light to moderate allergies, you can install a better air filter or change them even more frequently.

The quick answer to "how frequently should I change the air filter?":

If you don't have 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 models last longer?

Some air filters are manufactured to last up to six months, while others need to be replaced monthly. The denser the air filter, the longer it will last. Generally, you should check the thickness of the filter rather than the brand. You also need to look at the MERV Rating.

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

While a filter with a higher MERV Rating might last longer, it can also impede the flow of air in your home. And you will have to switch out the filter more often. And if you own an older piece of equipment, plan to substitute the filter more often to conserve the life of your filter.

How often do I have to exchange my air filter based on thickness?

The longevity of an air filter also depends on its thickness. A 1" filter will have to be changed out more frequently versus 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 3 months.
  • A 3” pleated air filter should be switched every 4 months.
  • A 4" pleated air filter ought to be swapped out every 6 months.
  • A 5” or 6" pleated air filter ought to be changed out every 9-12 months.

One of the perks of denser filters is not only do they live longer, but they also provide a higher 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 operate more efficiently and cut down on strain on components such as the blower motor.

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

How frequently should I change my air filter if I have a dog or cat?

If you have pets, you might have to change out your air filter more often. Pet hair and dander can easily clog an air filter and lower its effectiveness. For every shedding dog you own, expect to replace the filter a month earlier than you would in a home without pets. The same applies to cats, although they tend not to shed as often as dogs. If you own a hypoallergenic or non-shedding dog or cat, you might not need to replace your air filter as frequently.

Even though it's a good rule of thumb, you will need to check your air filter more frequently to determine if it needs to 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 monthly and exchange it when it appears clogged.

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

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