How often should I change my air filter at home?

How frequently you should change the air filters could rely on the following:

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

For standard 1"–3" air filters, manufacturers normally tell you to replace them every 30–90 days. If someone in your family suffers from light to moderate allergies, you can install a better air filter or replace them even more regularly.

The short answer to "how frequently do I need to replace the air filter?":

If you don't have a smoker or pets at home, and the 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 changing it.

What air filter brands survive longer?

A few air filters are supposed to last up to six months, while others have to be exchanged month-to-month. The larger the air filter, the longer it should last. Generally, you need to examine the thickness of the filter rather than the brand. You also need to consider at the MERV Rating.

The MERV Rating is a scale that goes from 1-20 and calculates how well an air filter will pull particles from the air. The better 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 might also restrict the flow of air in your home. And you will need to exchange the filter more frequently. And if you have an older system, plan to replace the filter more regularly to preserve the life of your filter.

How often should I switch out my air filter based on thickness?

The longevity of an air filter also counts on the thickness. A 1" filter will need to be changed out more frequently than a 4" filter.

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

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

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

How often should I replace my air filter if I own a dog or cat?

If you have pets, you might need to replace your air filter more frequently. Pet hair and dander can easily clog an air filter and reduce its effectiveness. For each shedding dog you want, expect to exchange the filter a month earlier than you would for a home without pets. The same applies to cats, although they don't shed as heavily as dogs. If you have a hypoallergenic or non-shedding dog or cat, you might not have to replace your air filter as often.

Although a good rule of thumb, you might want to check the air filter more frequently to decide if it should be replaced. Dogs usually do not shed the same amount year-round. They shed more in the spring and fall when they are blowing their coat. Take a look at the air filter every month and change it when it looks clogged.

Here are averages that can help you know how often you should get a new air filter at your residence:

Vacation house or a single occupant and no pets or allergies: every 6–12 months
Standard 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