How often should I change my air filter at home?

How regularly you need to replace the air filters can 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 common 1"–3" air filters, brands generally instruct you to replace them every 30–90 days. If you suffer from mild to moderate allergies, you could use a better air filter or replace them even more regularly.

The quick answer to "how frequently do I need to exchange 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 changing it.

What air filter models last longer?

Many air filters are manufactured to last up to six months, while others need to be switched month-to-month. The thicker the air filter, the longer it can last. Overall, you can examine the thickness of the filter versus the brand. You also need to check at the MERV Rating.

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

While a filter with a higher MERV Rating will last longer, it could also impede the airflow in your home. And you will have to exchange the filter more frequently. And if you acquire an older system, plan to switch out the filter more often to maintain the quality of your filter.

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

The lifespan of an air filter also relies on the thickness. A 1" filter will have to be replaced more often instead of a 4" filter.

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

One of the benefits of denser filters is not only do they last longer, but they also have a higher MERV Rating. This means they will do a more effective job of eliminating the particles inside your home. They also generate less air resistance, which can help ones HVAC system operate more effectively and reduce strain on components including the blower motor.

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

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

If you have pets, you might need to switch out your air filter more frequently. Pet hair and dander can easily clog an air filter and reduce 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 is true of cats, although they don't shed as often as dogs. If you own a hypoallergenic or non-shedding dog or cat, you might not have to exchange your air filter as often.

Despite being a good rule of thumb, you will need to examine your air filter more often to see if it has to be swapped out. Dogs don't shed at the same rate year-round. 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 seems clogged.

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

Vacation house or an individual 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