How frequently you should exchange the air filters could be on the following:
- Air filter design
- Total indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the residence
- The MERV Rating
For basic 1"–3" air filters, brands generally instruct you to exchange them every 30–90 days. If you suffer from mild to moderate allergies, you can install a better air filter or exchange them even more frequently.
The shortest answer to "how frequently do I have to switch out the air filter?":
If you don't have a smoker or pets at 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 survive longer?
Many air filters are manufactured to last up to six months, while others should be exchanged monthly. The denser the air filter, the longer it can last. In most cases, you can look at the thickness of the filter rather than the brand. You also need to consider at the MERV Rating.
The MERV Rating is a scale that stretches from 1-20 and assesses how well an air filter can eliminate 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 can last longer, it can also impede the flow of air in your home. And you will need to replace the filter more often. And if you own an older piece of equipment, plan to switch out the filter more frequently to extend the quality of your filter.
How often do I need to switch out my air filter based on thickness?
The longevity of an air filter also relies on the thickness. A 1" filter will have to be replaced more often than a 4" filter.
- A 1" pleated air filter ought to be replaced every 30-60 days.
- A 2" pleated air filter should be exchanged every 90 days.
- A 3” pleated air filter ought to be changed out every 4 months.
- A 4" pleated air filter should 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 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 getting rid of the particles within your home. They also generate less air resistance, which can help ones HVAC system run more effectively and cut down on strain on components including the blower motor.
If you want a whole-home air purifier, you will also have to exchange the filters more frequently.
How often should I change my air filter if I own a dog or cat?
If you want pets, you might have to exchange your air filter more frequently. Pet hair and dander can rapidly clog an air filter and reduce its effectiveness. For every shedding dog you have, expect to change out the filter a month earlier than you would in a home with no pets. The same is true of cats, although they don't shed as often as dogs. If you have a hypoallergenic or non-shedding dog or cat, you might not have to switch out your air filter as frequently.
Although a good rule of thumb, you might want to examine the air filter more regularly to see 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. Take a look at the air filter every month and change it when it looks clogged.
Here are averages that may help you know how frequently 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
- Average suburban home without pets: every 90 days
- A single dog or cat: every 2 months
- More than one pet or if somebody has allergies: 20–45 days