How often you should replace the air filters could rely on the following:
- Air filter model
- Total indoor air quality
- Quantity of pets
- Household size
- Air pollution levels and construction around the residence
- Your MERV Rating
For common 1"–3" air filters, manufacturers usually instruct you to replace them every 30–90 days. If you suffer from light to moderate allergies, you can put in a better air filter or replace them even more frequently.
The short answer to "how often should I swap the air filter?":
If there isn't a smoker or pets in your home, and the filter is the commonly 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 types last longer?
A few air filters are manufactured to last up to six months, while others need to be replaced monthly. The denser the air filter, the longer it can last. Overall, you should examine the thickness of the filter instead of 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 remove particles out of the air. The better the MERV Rating, the smaller the particle that could be captured by your air filter.
While a filter with a higher MERV Rating should last longer, it might also impede the circulation in your home. And you will have to switch out the filter more often. And if you own an older system, plan to replace the filter more regularly to maintain the life of your filter.
How frequently do I need to substitute my air filter based on thickness?
The lifespan of an air filter also relies on its thickness. A 1" filter will need to be replaced more often instead of a 4" filter.
- A 1" pleated air filter must be changed every 30-60 days.
- A 2" pleated air filter must be swapped out every 90 days.
- A 3” pleated air filter should be replaced every 4 months.
- A 4" pleated air filter must be swapped out every 6 months.
- A 5” or 6" pleated air filter ought to be changed out every 9-12 months.
One of the perks of denser filters is not only do they last longer, but they also provide a higher MERV Rating. This means they should do a more effective job of filtering out the particles within your home. They also generate less air resistance, which can help your HVAC system operate more proficiently and cut down on wear and tear on components such as the blower motor.
If you have a whole-house air purifier, you will also need to replace the filters more regularly.
How frequently should I change my air filter if I own a dog or cat?
If you want pets, you might have to switch out your air filter more often. Pet hair and dander can easily clog an air filter and minimize its effectiveness. For each shedding dog you want, expect to exchange the filter a month sooner than you would with a home with no pets. The same applies to cats, although they usually do not shed as heavily as dogs. If you have a hypoallergenic or non-shedding dog or cat, you might not need to switch out your air filter as frequently.
Despite being a good rule of thumb, you might want to examine 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. Check the air filter every month and change it when it looks clogged.
Here are averages that can help you understand how often you should put in a new air filter at your residence:
- Vacation house or an individual occupant and no pets or allergies: every 6–12 months
- Average suburban home without pets: every 90 days
- One dog or cat: every 60 days
- More than one pet or if a member of your family has allergies: 20–45 days