How often you should replace the air filters might be on the following:
- Air filter type
- Overall indoor air quality
- Quantity of pets
- Household size
- Air pollution levels and construction near the residence
- The MERV Rating
For standard 1"–3" air filters, brands typically ask you to swap them every 30–90 days. If someone in your family suffers from light to moderate allergies, you could use a better air filter or exchange them even more regularly.
The short answer to "how often do I have to exchange the air filter?":
If there isn't a smoker or pets at 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 switching it.
What air filter models survive longer?
A few air filters are supposed to survive up to six months, while others should be replaced monthly. The larger the air filter, the longer it will last. In general, you need to check the thickness of the filter instead of the brand. You also need to check at the MERV Rating.
The MERV Rating is a scale that goes from 1-20 and assesses how well an air filter can eliminate particles out of the air. The bigger the MERV Rating, the smaller the particle that will be caught by the air filter.
While a filter with a higher MERV Rating should last longer, it may also impede the flow of air in your home. And you will need to switch out the filter more often. And if you acquire an older system, plan to substitute the filter more regularly to conserve the life of your filter.
How regularly do I have to replace my air filter based on thickness?
The longevity of an air filter also relies on the thickness. A 1" filter will have to be exchanged more frequently instead of a 4" filter.
- A 1" pleated air filter ought to be replaced every 30-60 days.
- A 2" pleated air filter ought to be switched every 90 days.
- A 3” pleated air filter must be switched every 4 months.
- A 4" pleated air filter should be swapped out every 6 months.
- A 5” or 6" pleated air filter should 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 create less air resistance, which can help an HVAC system function more efficiently and decrease strain on components such as the blower motor.
If you have a whole-house air purifier, you will also need to exchange the filters more often.
How frequently should I replace my air filter if I want a dog or cat?
If you have pets, you might need to change out your air filter more frequently. Pet hair and dander can easily clog an air filter and reduce its effectiveness. For every shedding dog you want, expect to switch out the filter a month sooner than you would with a home lacking pets. The same is true of cats, although they don't shed as often as dogs. If you want a hypoallergenic or non-shedding dog or cat, you might not need to replace your air filter as much.
Even though it's a good rule of thumb, you will need to check on your air filter more regularly to decide if it needs to be replaced. Dogs don't shed the same amount all year. They shed more in the spring and fall when they are blowing their coat. Check the air filter each month and change it when it seems clogged.
Here are averages that may help you know 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
- Average suburban home without pets: every 90 days
- A single dog or cat: every 2 months
- More than one pet or if someone has allergies: 20–45 days