How often you should replace the air filters might be on the following:
- Air filter style
- Total indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction surrounding the residence
- The MERV Rating
For common 1"–3" air filters, manufacturers usually tell you to change them every 30–90 days. If someone in your family suffers from mild to moderate allergies, you could install a better air filter or replace them even more regularly.
The quick answer to "how frequently 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 models last longer?
A few air filters are supposed to last up to six months, while others need to be changed monthly. The denser the air filter, the longer it should last. Overall, you can check the thickness of the filter as opposed to the brand. You also need to take a look at the MERV Rating.
The MERV Rating is a scale that stretches from 1-20 and calculates how effectively an air filter will pull particles out of the air. The better the MERV Rating, the smaller the particle that will be captured by the air filter.
While a filter with a higher MERV Rating can last longer, it may also interfere with the airflow in your home. And you will need to change the filter more regularly. And if you have an older system, plan to substitute the filter more often to extend the life of your filter.
How regularly do I need to replace my air filter based on thickness?
The longevity of an air filter also depends on the thickness. A 1" filter will have to be swapped out more frequently versus a 4" filter.
- A 1" pleated air filter must be changed every 30-60 days.
- A 2" pleated air filter must be switched every 90 days.
- A 3” pleated air filter must be replaced every 120 days.
- A 4" pleated air filter must be changed out every 6 months.
- A 5” or 6" pleated air filter must be swapped every 9-12 months.
One of the benefits of thicker filters is not only do they last longer, but they also have a better MERV Rating. This means they should do a superior job of filtering out the particles within your home. They also create less air resistance, which can help your HVAC system work more effectively and cut down on strain on components like the blower motor.
If you have a whole-home air purifier, you will also need to switch out the filters more often.
How frequently should I change my air filter if I want a dog or cat?
If you want pets, you might need to change out your air filter more often. Pet hair and dander can quickly clog an air filter and reduce its effectiveness. For every shedding dog you own, expect to replace 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 often as dogs. If you have a hypoallergenic or non-shedding dog or cat, you might not have to replace your air filter as often.
Although a good rule of thumb, you might want to check on the air filter more frequently to decide if it needs to be exchanged. Dogs usually do not shed at the same rate all year. They shed more in the spring and fall when they are blowing their coat. Check the air filter each month and change it when it seems clogged.
Here are averages that might help you recognize how often you should put in a new air filter at your residence:
- Vacation house or a single occupant and no pets or allergies: every 6–12 months
- Average suburban home without pets: every 3 months
- A single dog or cat: every 60 days
- More than one pet or if a member of your family has allergies: 20–45 days