How frequently you should replace the air filters may rely on the following:
- Air filter model
- Overall indoor air quality
- Quantity of pets
- Household size
- Air pollution levels and construction around the residence
- The MERV Rating
For standard 1"–3" air filters, brands generally tell you to exchange them every 30–90 days. If someone in your family suffers from mild to moderate allergies, you can install a better air filter or replace them even more frequently.
The shortest answer to "how frequently do I have to exchange my air filter?":
If there isn't a smoker or pets in the home, and the filter is the widely 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 last longer?
Many air filters are manufactured to survive up to six months, while others need to be replaced month-to-month. The denser the air filter, the longer it can last. Overall, you should examine the thickness of the filter versus the brand. You also need to look at the MERV Rating.
The MERV Rating is a scale that goes from 1-20 and measures how well an air filter will pull particles from the air. The bigger the MERV Rating, the smaller the particle that can be captured by your air filter.
While a filter with a higher MERV Rating might last longer, it may also interfere with the circulation in your home. And you will have to replace the filter more regularly. And if you own an older piece of equipment, plan to change the filter more frequently to maintain the quality of your filter.
How frequently 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 replaced more often versus a 4" filter.
- A 1" pleated air filter must be changed every 30-60 days.
- A 2" pleated air filter ought to be switched every 90 days.
- A 3” pleated air filter ought to be exchanged every 120 days.
- A 4" pleated air filter should be replaced every 6 months.
- A 5” or 6" pleated air filter ought to be changed out every 9-12 months.
One of the benefits of denser filters is not only do they live longer, but they also posses a higher MERV Rating. This means they should do a more effective job of getting rid of the particles within your home. They also generate less air resistance, which can help ones HVAC system operate more efficiently and cut down on strain on components such as the blower motor.
If you own a whole-home air purifier, you will also need to exchange the filters more often.
How frequently should I replace my air filter if I have a dog or cat?
If you have pets, you might need to replace your air filter more often. Pet hair and dander can quickly clog an air filter and minimize its effectiveness. For every shedding dog you own, expect to exchange the filter a month earlier than you would with a home lacking pets. The same applies to cats, although they tend not to shed as often as dogs. If you want a hypoallergenic or non-shedding dog or cat, you might not have to switch out your air filter as frequently.
Even though it's a good rule of thumb, you might want to check the air filter more frequently to see if it needs to be replaced. Dogs usually do not 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 replace it when it appears clogged.
Here are averages that might help you learn how frequently you should get a new air filter at your residence:
- Vacation house or a single occupant and no pets or allergies: every 6–12 months
- Ordinary suburban home without pets: every 3 months
- A single dog or cat: every 2 months
- More than one pet or if a member of your family has allergies: 20–45 days