How frequently you should exchange the air filters may be on the following:
- Air filter type
- Total indoor air quality
- Quantity of pets
- Household size
- Air pollution levels and construction nearby the residence
- The MERV Rating
For basic 1"–3" air filters, brands generally ask you to change them every 30–90 days. If someone in your family suffers from mild to moderate allergies, you can put in a better air filter or replace them even more often.
The quick answer to "how frequently do I have to exchange the air filter?":
If there isn't a smoker or pets at 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 before switching it.
What air filter types last longer?
Some air filters are supposed to last up to six months, while others need to be changed each month. The larger the air filter, the longer it will last. In most cases, you need to examine the thickness of the filter instead of the brand. You also need to look at the MERV Rating.
The MERV Rating is a scale that stretches from 1-20 and calculates how effectively an air filter should eliminate particles out of the air. The better the MERV Rating, the smaller the particle that will be captured by your air filter.
While a filter with a higher MERV Rating can last longer, it may also hamper the circulation in your home. And you will need to replace the filter more regularly. And if you have an older piece of equipment, plan to switch out the filter more often to preserve the quality of your filter.
How frequently should I exchange my air filter based on thickness?
The longevity of an air filter also depends on the thickness. A 1" filter will have to be replaced more frequently compared to a 4" filter.
- A 1" pleated air filter must be changed every 30-60 days.
- A 2" pleated air filter ought to be swapped out every 3 months.
- A 3” pleated air filter should be exchanged every 4 months.
- 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 advantages of denser filters is not only do they survive longer, but they also have a higher MERV Rating. This means they can do a more effective job of getting rid of the particles in your home. They also create less air resistance, which can help an HVAC system work more proficiently 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 regularly should I exchange my air filter if I own a dog or cat?
If you have pets, you might need to replace your air filter more frequently. Pet hair and dander can rapidly clog an air filter and minimize its effectiveness. For every shedding dog you want, expect to switch out the filter a month sooner than you would for a home with no pets. The same is true of cats, although they usually do not shed as much as dogs. If you want a hypoallergenic or non-shedding dog or cat, you might not have to exchange your air filter as frequently.
Despite being a good rule of thumb, you will need to check on the air filter more often to figure out if it has to be swapped out. Dogs tend not to shed at the same rate year-round. 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 appears clogged.
Here are averages that might help you understand how often you should get a new air filter at your residence:
- Vacation house or one occupant and no pets or allergies: every 6–12 months
- Common suburban home without pets: every 90 days
- One dog or cat: every 2 months
- More than one pet or if a member of your family has allergies: 20–45 days