How often should I change my air filter at home?

change air filter

How frequently you need to replace your air filters could rely on the following:

  • Air filter type
  • Total indoor air quality
  • Number of pets
  • Household size
  • Air pollution levels and construction nearby the residence
  • The MERV Rating

For common 1"–3" air filters, companies usually instruct you to change them every 30–90 days. If you suffer from light to moderate allergies, you could use a better air filter or replace them even more regularly.

The short answer to "how often should I exchange my air filter?":

If you don't have a smoker or pets in your home, and the filter is the commonly sold 1" filter with a MERV rating of 4, you should be able to wait up to 90 days before switching it.

What air filter models survive longer?

Many air filters are designed to survive up to six months, while others need to be changed monthly. The larger the air filter, the longer it should last. In most cases, 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 stretches from 1-20 and calculates how effectively an air filter should pull particles out of the air. The better the MERV Rating, the smaller the particle that will be captured by the air filter.

While a filter with a higher MERV Rating might last longer, it could also restrict the ventilation in your home. And you will need to exchange the filter more regularly. And if you acquire an older system, plan to change the filter more frequently to extend the life of your filter.

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

The lifespan of an air filter also depends on its thickness. A 1" filter will need to be swapped out more often versus a 4" filter.

  • A 1" pleated air filter ought to be replaced every 30-60 days.
  • A 2" pleated air filter must be switched every 90 days.
  • A 3” pleated air filter must be replaced every 120 days.
  • A 4" pleated air filter should be changed out every 6 months.
  • A 5” or 6" pleated air filter must be replaced every 9-12 months.

One of the perks of thicker filters is not only do they survive longer, but they also boast a higher MERV Rating. This means they can do a more effective job of eliminating the particles within your home. They also create less air resistance, which can help an HVAC system run more proficiently and limit wear and tear on components including the blower motor.

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

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

If you own pets, you might need to switch out your air filter more frequently. Pet hair and dander can quickly clog an air filter and limit its effectiveness. For each shedding dog you have, expect to change out the filter a month earlier than you would for a home lacking pets. The same is true of 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 replace your air filter as often.

Even though it's a good rule of thumb, you will need to check the air filter more regularly to determine if it needs to be swapped out. Dogs tend not to shed at the same rate year-round. They shed more in the spring and fall when they are blowing their coat. Check the air filter each month and replace it when it seems clogged.

Here are averages that may help you recognize how regularly you should get a new air filter at your residence:

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