How often you have to replace the air filters can be on the following:
- Air filter model
- Total indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction near the residence
- The MERV Rating
For basic 1"–3" air filters, brands normally ask you to exchange 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 quick answer to "how often do I need to switch out the air filter?":
If you don't have a smoker or pets at home, and the filter is the often 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 styles last longer?
Some air filters are supposed to last up to six months, while others need to be exchanged month-to-month. The larger the air filter, the longer it can last. Generally, you should check 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 should eliminate 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 will last longer, it may also hamper the circulation in your home. And you will need to exchange the filter more often. And if you own an older system, plan to switch out the filter more often to extend the quality of your filter.
How frequently do I need to substitute my air filter based on thickness?
The lifespan of an air filter also depends on the thickness. A 1" filter will need to be changed out more frequently compared to a 4" filter.
- A 1" pleated air filter should be changed out every 30-60 days.
- A 2" pleated air filter must be exchanged every 3 months.
- A 3” pleated air filter ought to be switched every 4 months.
- A 4" pleated air filter must be changed out every 6 months.
- A 5” or 6" pleated air filter should be swapped every 9-12 months.
One of the advantages of denser filters is not only do they last longer, but they also posses a higher MERV Rating. This means they can do a more effective job of filtering out the particles inside your home. They also generate less air resistance, which can help ones HVAC system function more efficiently and decrease wear and tear on components including the blower motor.
If you have a whole-house air purifier, you will also have to switch out the filters more regularly.
How often should I replace my air filter if I have 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 minimize its effectiveness. For each shedding dog you own, expect to change out the filter a month sooner than you would for a home lacking pets. The same goes for cats, although they usually do not shed as often as dogs. If you own a hypoallergenic or non-shedding dog or cat, you might not need to switch out your air filter as often.
Although a good rule of thumb, you might want to examine your air filter more often to figure out if it needs to be replaced. Dogs usually do not shed the same amount 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 can help you learn how frequently you should get a new air filter at your residence:
- Vacation house or a single occupant and no pets or allergies: every 6–12 months
- Ordinary suburban home without pets: every 90 days
- A single dog or cat: every 2 months
- More than one pet or if a member of your family has allergies: 20–45 days