How frequently you need to exchange the air filters can be on the following:
- Air filter design
- Overall indoor air quality
- Quantity of pets
- Household size
- Air pollution levels and construction surrounding the residence
- The MERV Rating
For standard 1"–3" air filters, brands typically tell you to exchange them every 30–90 days. If you suffer from light to moderate allergies, you could put in a better air filter or change them even more often.
The short answer to "how often do I have to switch out the air filter?":
If you don't have a smoker or pets in the 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?
Many air filters are supposed to survive up to six months, while others need to be changed monthly. The denser the air filter, the longer it can last. In general, you need to look at the thickness of the filter versus the brand. You also need to look at the MERV Rating.
The MERV Rating is a scale that records from 1-20 and calculates how well an air filter should eliminate particles out of 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 could also impede the airflow in your home. And you will have to replace the filter more regularly. And if you own an older piece of equipment, plan to replace the filter more often to preserve the life of your filter.
How often should I exchange my air filter based on thickness?
The lifespan of an air filter also hinges on its thickness. A 1" filter will need to be replaced more often compared to a 4" filter.
- A 1" pleated air filter should be exchanged every 30-60 days.
- A 2" pleated air filter must be exchanged every 3 months.
- A 3” pleated air filter ought to be changed out every 120 days.
- A 4" pleated air filter ought to be changed out every 6 months.
- A 5” or 6" pleated air filter should be replaced every 9-12 months.
One of the advantages of denser filters is not only do they last longer, but they also posses a better MERV Rating. This means they should do a superior job of filtering out the particles within your home. They also create less air resistance, which can help an HVAC system operate more efficiently and reduce wear and tear on components like the blower motor.
If you own a whole-house air purifier, you will also have to replace the filters more often.
How frequently should I change my air filter if I own a dog or cat?
If you want pets, you might need to replace your air filter more frequently. Pet hair and dander can rapidly clog an air filter and limit its effectiveness. For each shedding dog you own, expect to switch out the filter a month earlier than you would with a home without pets. The same goes for 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 change out your air filter as frequently.
Even though it's a good rule of thumb, you might want to examine the air filter more regularly to determine if it should be swapped out. Dogs usually do not shed the same amount year-round. They shed more in the spring and fall when they are blowing their coat. Inspect the air filter monthly and change it when it looks clogged.
Here are averages that may help you understand how often you should put in a new air filter at your residence:
- Vacation house or an individual occupant and no pets or allergies: every 6–12 months
- Ordinary suburban home without pets: every 3 months
- One dog or cat: every 60 days
- More than one pet or if someone has allergies: 20–45 days