How frequently you have to exchange the air filters can rely on the following:
- Air filter style
- Overall 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, companies typically tell you to swap them every 30–90 days. If you suffer from mild to moderate allergies, you can put in a better air filter or change them even more often.
The short answer to "how frequently do I need to replace my air filter?":
If you don't have a smoker or pets in your home, and your filter is the widely 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 brands last longer?
A few air filters are manufactured to last up to six months, while others need to be switched each month. The thicker the air filter, the longer it should last. In most cases, you should 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 measures how efficiently an air filter will eliminate particles from the air. The higher the MERV Rating, the smaller the particle that will be captured by your air filter.
While a filter with a higher MERV Rating will last longer, it can also restrict the airflow in your home. And you will have to exchange the filter more often. And if you own an older system, plan to change the filter more frequently to extend the quality of your filter.
How often do I need to exchange my air filter based on thickness?
The longevity of an air filter also depends on its thickness. A 1" filter will need to be changed out more often instead of a 4" filter.
- A 1" pleated air filter ought to be changed every 30-60 days.
- A 2" pleated air filter must be exchanged every 3 months.
- A 3” pleated air filter ought to be replaced every 120 days.
- A 4" pleated air filter must be changed out every 6 months.
- A 5” or 6" pleated air filter should be replaced every 9-12 months.
One of the advantages of thicker filters is not only do they last longer, but they also boast a better MERV Rating. This means they will do a better job of getting rid of the particles in your home. They also create less air resistance, which can help an HVAC system operate more effectively and cut down on wear and tear on components like the blower motor.
If you own a whole-house air purifier, you will also have to switch out the filters more frequently.
How regularly should I change my air filter if I own a dog or cat?
If you own pets, you might have to exchange your air filter more often. Pet hair and dander can easily clog an air filter and minimize its effectiveness. For every shedding dog you own, expect to switch out the filter a month earlier than you would for a home with no pets. The same applies to cats, although they usually do not shed as much as dogs. If you own a hypoallergenic or non-shedding dog or cat, you might not have to change out your air filter as often.
Even though it's a good rule of thumb, you might want to examine the air filter more regularly 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. Take a look at the air filter every month and replace it when it seems clogged.
Here are averages that can help you recognize how frequently you should install 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 60 days
- More than one pet or if somebody has allergies: 20–45 days