How often you have to replace the air filters could rely on the following:
- Air filter style
- Overall indoor air quality
- Quantity of pets
- Household size
- Air pollution levels and construction near the residence
- The MERV Rating
For basic 1"–3" air filters, manufacturers generally ask you to replace them every 30–90 days. If you suffer from light to moderate allergies, you could use a better air filter or change them even more often.
The shortest answer to "how frequently do I need to replace the air filter?":
If you don't have a smoker or pets in your 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 brands survive longer?
Some air filters are manufactured to survive up to six months, while others have to be swapped monthly. The larger the air filter, the longer it can last. In most cases, you need to examine the thickness of the filter rather than the brand. You also need to look at the MERV Rating.
The MERV Rating is a scale that stretches from 1-20 and measures how effectively an air filter can eliminate particles from the air. The higher the MERV Rating, the smaller the particle that will be captured by the air filter.
While a filter with a higher MERV Rating can last longer, it might also hamper the airflow in your home. And you will need to switch out the filter more often. And if you have an older system, plan to exchange the filter more frequently to conserve the life of your filter.
How often should I substitute my air filter based on thickness?
The longevity of an air filter also relies on its thickness. A 1" filter will have to be changed out more frequently versus a 4" filter.
- A 1" pleated air filter ought to be changed every 30-60 days.
- A 2" pleated air filter ought to be switched every 90 days.
- A 3” pleated air filter must be exchanged every 120 days.
- A 4" pleated air filter should be exchanged every 6 months.
- A 5” or 6" pleated air filter must be changed out every 9-12 months.
One of the benefits of thicker filters is not only do they last longer, but they also provide a higher MERV Rating. This means they can do a more effective job of filtering out the particles in your home. They also generate less air resistance, which can help an HVAC system work more efficiently and cut down on wear and tear on components like the blower motor.
If you want a whole-house air purifier, you will also have to replace the filters more often.
How regularly should I replace my air filter if I have a dog or cat?
If you own pets, you might need to replace your air filter more frequently. Pet hair and dander can easily clog an air filter and limit its effectiveness. For each shedding dog you have, expect to change out the filter a month earlier than you would for a home without pets. The same goes for cats, although they don't 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 much.
Even though it's a good rule of thumb, you might want to check on your air filter more frequently to determine if it needs to be swapped out. Dogs usually do not shed at the same rate year-round. They shed more in the spring and fall when they are blowing their coat. Inspect the air filter monthly and change it when it appears clogged.
Here are averages that may help you know how regularly you should get a new air filter at your residence:
- Vacation house or one occupant and no pets or allergies: every 6–12 months
- Average suburban home without pets: every 3 months
- A single dog or cat: every 60 days
- More than one pet or if anyone has allergies: 20–45 days