How frequently you should change the air filters might depend on the following:
- Air filter type
- Total indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction surrounding the residence
- The MERV Rating
For basic 1"–3" air filters, companies generally tell you to swap them every 30–90 days. If someone in your family suffers from mild to moderate allergies, you can install a better air filter or change them even more frequently.
The quick answer to "how frequently do I have to switch out my air filter?":
If you don't have a smoker or pets in your 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 prior to switching it.
What air filter models last longer?
Some air filters are supposed to survive up to six months, while others need to be switched month-to-month. The thicker the air filter, the longer it should last. In most cases, you need to look at the thickness of the filter rather than the brand. You also need to take a look at the MERV Rating.
The MERV Rating is a scale that records from 1-20 and assesses how effectively an air filter will pull particles from the air. The bigger the MERV Rating, the smaller the particle that can be captured by your air filter.
While a filter with a higher MERV Rating might last longer, it might also hamper the ventilation in your home. And you will have to replace the filter more frequently. And if you own an older system, plan to change the filter more regularly to maintain the life of your filter.
How often do I need to substitute my air filter based on thickness?
The longevity of an air filter also depends on its thickness. A 1" filter will need to be swapped out more frequently instead of a 4" filter.
- A 1" pleated air filter must be changed out every 30-60 days.
- A 2" pleated air filter ought to be switched every 90 days.
- A 3” pleated air filter ought to be replaced every 4 months.
- A 4" pleated air filter ought to be changed out every 6 months.
- A 5” or 6" pleated air filter must be changed out every 9-12 months.
One of the perks of thicker filters is not only do they survive longer, but they also provide a higher MERV Rating. This means they will do a superior job of eliminating the particles inside your home. They also generate less air resistance, which can help ones HVAC system function more effectively and reduce wear and tear on components like the blower motor.
If you have a whole-home air purifier, you will also have to switch out the filters more regularly.
How frequently should I change 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 quickly clog an air filter and lower its effectiveness. For each shedding dog you own, expect to exchange the filter a month earlier than you would for a home with no pets. The same is true of 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 need to exchange your air filter as much.
Although a good rule of thumb, you might want to examine the air filter more frequently to see if it needs to be exchanged. 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 each month and exchange it when it seems clogged.
Here are averages that can help you learn how regularly you should put in 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 a member of your family has allergies: 20–45 days