How frequently you need to replace the air filters could depend on the following:
- Air filter type
- Overall 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 light to moderate allergies, you could use a better air filter or exchange them even more frequently.
The short answer to "how often should I swap the air filter?":
If you don't have a smoker or pets in the 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 before changing it.
What air filter types survive longer?
A few air filters are supposed to last up to six months, while others have to be exchanged month-to-month. The denser the air filter, the longer it should last. Generally, you need to look at 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 records from 1-20 and calculates how well an air filter should eliminate particles from the air. The higher the MERV Rating, the smaller the particle that can be captured by the air filter.
While a filter with a higher MERV Rating might last longer, it can also interfere with the airflow in your home. And you will need to switch out the filter more regularly. And if you acquire an older system, plan to replace the filter more regularly to extend the quality of your filter.
How frequently do I have to replace my air filter based on thickness?
The longevity of an air filter also depends on the thickness. A 1" filter will need to be replaced more often than a 4" filter.
- A 1" pleated air filter must be changed out every 30-60 days.
- A 2" pleated air filter should be switched every 90 days.
- A 3” pleated air filter must be replaced every 120 days.
- A 4" pleated air filter ought to be exchanged every 6 months.
- A 5” or 6" pleated air filter must be changed out every 9-12 months.
One of the advantages of denser filters is not only do they survive longer, but they also posses a higher MERV Rating. This means they should do a superior job of filtering out the particles in your home. They also create less air resistance, which can help your HVAC system work more effectively and limit strain on components like the blower motor.
If you want a whole-house air purifier, you will also have to switch out the filters more regularly.
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 often. Pet hair and dander can easily clog an air filter and minimize its effectiveness. For every shedding dog you have, expect to replace the filter a month earlier than you would for a home with no pets. The same is true of cats, although they tend not to shed as often as dogs. If you want a hypoallergenic or non-shedding dog or cat, you might not need to change out your air filter as often.
Although a good rule of thumb, you might want to check your air filter more regularly to figure out if it needs 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. Take a look at the air filter every month and change it when it looks clogged.
Here are averages that might help you recognize how often you should get a new air filter at your residence:
- Vacation house or an individual occupant and no pets or allergies: every 6–12 months
- Common suburban home without pets: every 90 days
- A single dog or cat: every 60 days
- More than one pet or if a member of your family has allergies: 20–45 days