How often should I change my air filter at home?

How regularly you need to change your air filters might be on the following:

Air filter design
Total 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, brands generally ask you to swap them every 30–90 days. If someone in your family suffers from mild to moderate allergies, you can install a better air filter or replace them even more frequently.

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

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

What air filter styles last longer?

Some air filters are designed to survive up to six months, while others need to be swapped monthly. The thicker the air filter, the longer it should last. Overall, you can check the thickness of the filter instead of the brand. You also need to take a look at the MERV Rating.

The MERV Rating is a scale that records from 1-20 and measures how efficiently an air filter will remove particles from the air. The bigger the MERV Rating, the smaller the particle that could be caught by the air filter.

While a filter with a higher MERV Rating will last longer, it may also interfere with the ventilation in your home. And you will need to replace the filter more often. And if you have an older system, plan to change the filter more frequently to preserve the quality of your filter.

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

The lifespan of an air filter also counts on the thickness. A 1" filter will need to be swapped out more often than a 4" filter.

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

One of the advantages of denser filters is not only do they last longer, but they also provide a higher MERV Rating. This means they can do a better job of filtering out the particles within your home. They also produce less air resistance, which can help an HVAC system work more proficiently and cut down on wear and tear on components like the blower motor.

If you want a whole-home air purifier, you will also need to exchange the filters more regularly.

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

If you own pets, you might need to change out your air filter more regularly. Pet hair and dander can quickly clog an air filter and limit its effectiveness. For every shedding dog you have, expect to replace the filter a month earlier than you would for a home without pets. The same is true of cats, although they usually do not shed as much as dogs. If you own a hypoallergenic or non-shedding dog or cat, you might not need to replace your air filter as frequently.

Despite being a good rule of thumb, you might want to check on your air filter more regularly to see if it should be exchanged. Dogs usually do not 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 monthly and replace it when it seems clogged.

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

Vacation house or a single occupant and no pets or allergies: every 6–12 months
Common suburban home without pets: every 90 days
One dog or cat: every 2 months
More than one pet or if anyone has allergies: 20–45 days