How frequently you should exchange the air filters might rely on the following:
- Air filter model
- Overall indoor air quality
- Quantity of pets
- Household size
- Air pollution levels and construction surrounding the residence
- Your MERV Rating
For common 1"–3" air filters, manufacturers normally ask you to change them every 30–90 days. If you suffer from light to moderate allergies, you can put in a better air filter or exchange them even more often.
The shortest answer to "how often should I swap the air filter?":
If there isn't a smoker or pets in your 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 prior to changing it.
What air filter types survive longer?
Some air filters are manufactured to last up to six months, while others need to be swapped each month. The larger the air filter, the longer it should last. In general, you need to examine the thickness of the filter versus 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 effectively an air filter will pull particles from the air. The bigger the MERV Rating, the smaller the particle that will be captured by your air filter.
While a filter with a higher MERV Rating should last longer, it can also hamper the airflow in your home. And you will need to replace the filter more frequently. And if you own an older piece of equipment, plan to switch out the filter more often to extend the life of your filter.
How often do I have to switch out my air filter based on thickness?
The longevity of an air filter also hinges on its thickness. A 1" filter will have to be replaced more often compared to a 4" filter.
- A 1" pleated air filter must be changed out every 30-60 days.
- A 2" pleated air filter should be exchanged every 3 months.
- A 3” pleated air filter must be changed out every 120 days.
- A 4" pleated air filter ought to be changed out every 6 months.
- A 5” or 6" pleated air filter must be swapped every 9-12 months.
One of the perks of thicker filters is not only do they survive longer, but they also provide a higher MERV Rating. This means they will do a better job of getting rid of the particles inside your home. They also produce less air resistance, which can help ones HVAC system operate more proficiently and decrease wear and tear on components including the blower motor.
If you have a whole-house air purifier, you will also have to replace the filters more often.
How often should I replace my air filter if I own a dog or cat?
If you want pets, you might need to replace your air filter more often. Pet hair and dander can rapidly clog an air filter and reduce its effectiveness. For each shedding dog you have, expect to replace the filter a month sooner than you would for a home with no pets. The same goes for cats, although they usually do not shed as heavily as dogs. If you have a hypoallergenic or non-shedding dog or cat, you might not have to exchange your air filter as often.
Although a good rule of thumb, you might want to check on your air filter more regularly to see if it needs to be exchanged. Dogs don't shed the same amount year-round. They shed more in the spring and fall when they are blowing their coat. Inspect the air filter monthly and replace it when it looks clogged.
Here are averages that may help you learn how regularly you should get a new air filter at your residence:
- Vacation house or an individual occupant and no pets or allergies: every 6–12 months
- Standard suburban home without pets: every 3 months
- A single dog or cat: every 2 months
- More than one pet or if anyone has allergies: 20–45 days