How often should I change my air filter at home?

How often you have to replace the air filters can be on the following:

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

For basic 1"–3" air filters, manufacturers usually ask you to replace them every 30–90 days. If you suffer from mild to moderate allergies, you could put in a better air filter or change them even more often.

The shortest answer to "how frequently do I have to exchange my air filter?":

If there isn't a smoker or pets in the 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 before replacing it.

What air filter styles survive longer?

Many air filters are supposed to last up to six months, while others should be switched each month. The larger the air filter, the longer it should last. Overall, you need to examine the thickness of the filter as opposed to the brand. You also need to consider at the MERV Rating.

The MERV Rating is a scale that records from 1-20 and measures how efficiently an air filter can remove particles out of the air. The higher the MERV Rating, the smaller the particle that could be captured by the air filter.

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

How frequently do I need to exchange my air filter based on thickness?

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

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

One of the benefits of denser filters is not only do they live longer, but they also posses a higher MERV Rating. This means they can do a more effective job of filtering out the particles in your home. They also produce less air resistance, which can help ones HVAC system operate more proficiently and limit wear and tear on components including the blower motor.

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

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

If you have pets, you might have to change out your air filter more regularly. Pet hair and dander can easily clog an air filter and limit its effectiveness. For each shedding dog you have, expect to exchange the filter a month sooner than you would with a home without pets. The same goes for cats, although they usually do not shed as heavily as dogs. If you own a hypoallergenic or non-shedding dog or cat, you might not need to switch out your air filter as often.

Despite being a good rule of thumb, you will need to check on the air filter more frequently to see if it needs to be exchanged. Dogs usually do not shed at the same rate all year. They shed more in the spring and fall when they are blowing their coat. Take a look at the air filter each month and replace it when it appears clogged.

Here are averages that can help you understand how frequently 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
Average suburban home without pets: every 3 months
One dog or cat: every 2 months
More than one pet or if someone has allergies: 20–45 days