How frequently you have to exchange the air filters may be on the following:
- Air filter style
- Total indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the residence
- Your MERV Rating
For basic 1"–3" air filters, companies generally tell you to replace them every 30–90 days. If you suffer from light to moderate allergies, you can put in a better air filter or replace them even more frequently.
The short answer to "how frequently should I switch out my air filter?":
If you don't have a smoker or pets at 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 replacing it.
What air filter models last longer?
Many air filters are supposed to last up to six months, while others should be exchanged each month. The larger the air filter, the longer it can last. In most cases, you can examine the thickness of the filter versus the brand. You also need to look at the MERV Rating.
The MERV Rating is a scale that goes from 1-20 and calculates how well an air filter will remove particles out of 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 might last longer, it could also hamper the flow of air in your home. And you will need to switch out the filter more often. And if you own an older system, plan to exchange the filter more often to extend the quality of your filter.
How often do I need to switch out my air filter based on thickness?
The longevity of an air filter also hinges on its thickness. A 1" filter will have to be swapped out more often instead of a 4" filter.
- A 1" pleated air filter ought to be exchanged every 30-60 days.
- A 2" pleated air filter ought to be exchanged every 90 days.
- A 3” pleated air filter should be switched every 4 months.
- A 4" pleated air filter should be replaced every 6 months.
- A 5” or 6" pleated air filter must be swapped every 9-12 months.
One of the benefits of thicker filters is not only do they survive longer, but they also have a higher MERV Rating. This means they can do a superior job of eliminating the particles in your home. They also produce less air resistance, which can help ones HVAC system function more proficiently and reduce wear and tear on components such as the blower motor.
If you own a whole-home air purifier, you will also need to exchange the filters more regularly.
How frequently should I exchange my air filter if I have a dog or cat?
If you want pets, you might need to switch out your air filter more frequently. Pet hair and dander can easily clog an air filter and lower its effectiveness. For each shedding dog you have, expect to change out the filter a month sooner than you would in a home without pets. The same goes for cats, although they usually do not shed as heavily as dogs. If you own a hypoallergenic or non-shedding dog or cat, you might not have to exchange your air filter as often.
Despite being a good rule of thumb, you might want to examine the air filter more regularly to determine if it has 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. Inspect the air filter each month and replace it when it appears clogged.
Here are averages that might help you learn how frequently 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 90 days
- One dog or cat: every 2 months
- More than one pet or if a member of your family has allergies: 20–45 days