How often you should exchange your air filters may be on the following:
- Air filter type
- Total indoor air quality
- Quantity of pets
- Household size
- Air pollution levels and construction nearby the residence
- Your MERV Rating
For basic 1"–3" air filters, manufacturers usually tell you to change them every 30–90 days. If someone in your family suffers from light to moderate allergies, you can put in a better air filter or exchange them even more frequently.
The short answer to "how often should I replace my air filter?":
If you don't have a smoker or pets in your 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 models survive longer?
Some air filters are manufactured to last up to six months, while others have to be changed month-to-month. The denser the air filter, the longer it will last. In most cases, you need to examine the thickness of the filter instead of the brand. You also need to take a look at the MERV Rating.
The MERV Rating is a scale that goes from 1-20 and assesses how efficiently an air filter should remove particles from the air. The bigger the MERV Rating, the smaller the particle that will be captured by the air filter.
While a filter with a higher MERV Rating will last longer, it could also impede the circulation in your home. And you will need to replace the filter more often. And if you acquire an older system, plan to exchange the filter more often to extend the quality of your filter.
How regularly do I have to replace my air filter based on thickness?
The lifespan of an air filter also counts on the thickness. A 1" filter will have to be changed out more frequently 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 switched every 3 months.
- A 3” pleated air filter must be changed out every 4 months.
- A 4" pleated air filter must be exchanged 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 survive longer, but they also provide a higher MERV Rating. This means they will do a better job of getting rid of the particles within your home. They also generate less air resistance, which can help your HVAC system work more effectively and reduce strain on components like the blower motor.
If you have a whole-house air purifier, you will also need to replace the filters more frequently.
How often should I change my air filter if I have a dog or cat?
If you have pets, you might need to exchange your air filter more regularly. Pet hair and dander can quickly clog an air filter and reduce its effectiveness. For every shedding dog you own, expect to replace the filter a month sooner than you would with a home without pets. The same goes for cats, although they tend not to shed as often as dogs. If you own a hypoallergenic or non-shedding dog or cat, you might not have to exchange your air filter as frequently.
Even though it's a good rule of thumb, you will need to check on the air filter more frequently to decide if it needs to be swapped out. Dogs don't shed at the same rate year-round. They shed more in the spring and fall when they are blowing their coat. Check the air filter every month and change it when it appears clogged.
Here are averages that may help you know how regularly you should put in a new air filter at your residence:
- Vacation house or a single 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 somebody has allergies: 20–45 days