How frequently you have to exchange the air filters might depend on the following:
- Air filter type
- Overall indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the residence
- Your MERV Rating
For standard 1"–3" air filters, companies typically instruct you to exchange them every 30–90 days. If you suffer from mild to moderate allergies, you can put in a better air filter or change them even more regularly.
The short answer to "how often do I need to swap the air filter?":
If there isn't a smoker or pets in your home, and the filter is the often 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 last longer?
Some air filters are designed to last up to six months, while others need to be changed month-to-month. The denser the air filter, the longer it can last. In general, you should examine the thickness of the filter versus the brand. You also need to take a look at the MERV Rating.
The MERV Rating is a scale that goes from 1-20 and measures how well an air filter should eliminate particles from the air. The bigger the MERV Rating, the smaller the particle that will be caught by the air filter.
While a filter with a higher MERV Rating can last longer, it might also hamper the flow of air in your home. And you will have to switch out the filter more often. And if you have an older system, plan to change the filter more regularly to preserve the quality of your filter.
How frequently do I need to exchange my air filter based on thickness?
The longevity of an air filter also counts on the thickness. A 1" filter will have to be replaced more often versus a 4" filter.
- A 1" pleated air filter ought to be changed out every 30-60 days.
- A 2" pleated air filter should be exchanged every 90 days.
- A 3” pleated air filter should 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 replaced every 9-12 months.
One of the benefits of thicker 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 getting rid of the particles in your home. They also generate less air resistance, which can help your HVAC system operate more effectively and decrease wear and tear on components like the blower motor.
If you own a whole-home air purifier, you will also have to exchange the filters more regularly.
How frequently should I exchange my air filter if I want a dog or cat?
If you want pets, you might have to switch out your air filter more regularly. Pet hair and dander can quickly clog an air filter and minimize its effectiveness. For every shedding dog you want, expect to change out the filter a month sooner than you would with a home without pets. The same is true of cats, although they tend not to shed as often as dogs. If you have a hypoallergenic or non-shedding dog or cat, you might not have to exchange your air filter as frequently.
Despite being a good rule of thumb, you might want to check your air filter more frequently to determine 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. Check the air filter monthly and change it when it looks clogged.
Here are averages that might help you learn how frequently you should put in a new air filter at your residence:
- Vacation house or one occupant and no pets or allergies: every 6–12 months
- Standard suburban home without pets: every 3 months
- One dog or cat: every 60 days
- More than one pet or if somebody has allergies: 20–45 days