How often you need to exchange your air filters might rely on the following:
- Air filter style
- Total indoor air quality
- Quantity of pets
- Household size
- Air pollution levels and construction nearby the residence
- The MERV Rating
For common 1"–3" air filters, brands usually ask you to swap them every 30–90 days. If you suffer from mild to moderate allergies, you can put in a better air filter or replace 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 prior to switching it.
What air filter models survive longer?
A few air filters are manufactured to survive up to six months, while others need to be swapped each month. The thicker the air filter, the longer it will last. Overall, you need to examine the thickness of the filter instead of the brand. You also need to check at the MERV Rating.
The MERV Rating is a scale that stretches from 1-20 and assesses how effectively an air filter will eliminate particles out of the air. The bigger the MERV Rating, the smaller the particle that will be captured by your air filter.
While a filter with a higher MERV Rating might last longer, it might also restrict the airflow in your home. And you will need to exchange the filter more often. And if you have an older system, plan to change the filter more often to extend the quality of your filter.
How frequently should I 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 compared to a 4" filter.
- A 1" pleated air filter should be changed out every 30-60 days.
- A 2" pleated air filter should be replaced every 3 months.
- A 3” pleated air filter should be replaced every 120 days.
- A 4" pleated air filter should be exchanged every 6 months.
- A 5” or 6" pleated air filter should be swapped every 9-12 months.
One of the benefits of denser filters is not only do they live longer, but they also boast a better MERV Rating. This means they will do a superior job of getting rid of the particles inside your home. They also generate less air resistance, which can help an HVAC system run more effectively and reduce strain on components like the blower motor.
If you have a whole-house air purifier, you will also need to switch out the filters more regularly.
How frequently should I change my air filter if I have a dog or cat?
If you want pets, you might need to exchange your air filter more frequently. Pet hair and dander can quickly 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 with no pets. The same applies to cats, although they tend not to shed as much as dogs. If you want a hypoallergenic or non-shedding dog or cat, you might not need to replace your air filter as frequently.
Even though it's a good rule of thumb, you might want to check on your air filter more often to figure out if it should be replaced. Dogs tend not to shed the same amount all year. They shed more in the spring and fall when they are blowing their coat. Take a look at the air filter monthly and replace it when it appears clogged.
Here are averages that might help you know how frequently you should install 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