How frequently you have to change your air filters may rely on the following:
- Air filter design
- Total indoor air quality
- Quantity of pets
- Household size
- Air pollution levels and construction surrounding the residence
- The MERV Rating
For common 1"–3" air filters, manufacturers typically ask you to swap them every 30–90 days. If you suffer from light to moderate allergies, you can use a better air filter or replace them even more often.
The shortest answer to "how often should I change the air filter?":
If you don't have 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 before replacing it.
What air filter models survive longer?
A few air filters are supposed to survive up to six months, while others need to be changed monthly. The thicker the air filter, the longer it will last. Overall, you need to examine the thickness of the filter versus the brand. You also need to check at the MERV Rating.
The MERV Rating is a scale that records from 1-20 and assesses how well an air filter can pull particles from the air. The higher the MERV Rating, the smaller the particle that will be captured by the air filter.
While a filter with a higher MERV Rating will last longer, it could also impede the flow of air in your home. And you will have to replace the filter more often. And if you have an older system, plan to switch out the filter more frequently to conserve the life of your filter.
How often do I have to substitute my air filter based on thickness?
The lifespan of an air filter also depends on the thickness. A 1" filter will have to be swapped out more frequently than a 4" filter.
- A 1" pleated air filter ought to be exchanged every 30-60 days.
- A 2" pleated air filter ought to be exchanged every 3 months.
- A 3” pleated air filter ought to be exchanged every 120 days.
- A 4" pleated air filter should be changed out every 6 months.
- A 5” or 6" pleated air filter ought to be replaced every 9-12 months.
One of the perks of thicker filters is not only do they last longer, but they also have a higher MERV Rating. This means they can do a better job of filtering out the particles within your home. They also generate less air resistance, which can help your HVAC system function more effectively and decrease wear and tear on components such as the blower motor.
If you have a whole-house air purifier, you will also have to exchange the filters more regularly.
How frequently should I replace my air filter if I have a dog or cat?
If you own pets, you might need to exchange your air filter more frequently. Pet hair and dander can quickly clog an air filter and limit its effectiveness. For each shedding dog you own, expect to change out the filter a month sooner than you would with a home with no pets. The same goes for cats, although they tend not to shed as heavily as dogs. If you have a hypoallergenic or non-shedding dog or cat, you might not need to exchange your air filter as frequently.
Despite being a good rule of thumb, you might want to check your air filter more often to determine if it should be exchanged. 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 monthly and replace it when it looks clogged.
Here are averages that can help you understand how regularly 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 3 months
- A single dog or cat: every 60 days
- More than one pet or if anyone has allergies: 20–45 days