How often you have to change your air filters could be on the following:
- Air filter type
- Overall indoor air quality
- Quantity of pets
- Household size
- Air pollution levels and construction near the residence
- The MERV Rating
For standard 1"–3" air filters, manufacturers typically ask you to exchange them every 30–90 days. If you suffer from mild to moderate allergies, you can use a better air filter or replace them even more regularly.
The short answer to "how often do I have to swap the air filter?":
If you don't have a smoker or pets in your home, and the filter is the commonly sold 1" filter with a MERV rating of 4, you should be able to wait up to 90 days prior to changing it.
What air filter types last longer?
A few air filters are designed to survive up to six months, while others should be changed month-to-month. The denser the air filter, the longer it should last. Overall, you should look at the thickness of the filter instead of the brand. You also need to look at the MERV Rating.
The MERV Rating is a scale that records from 1-20 and assesses how well an air filter will pull particles from the air. The higher the MERV Rating, the smaller the particle that could be captured by your air filter.
While a filter with a higher MERV Rating can last longer, it could also restrict the ventilation in your home. And you will have to exchange the filter more frequently. And if you own an older piece of equipment, plan to switch out the filter more often to maintain the life of your filter.
How frequently do I need to replace my air filter based on thickness?
The lifespan of an air filter also relies on its thickness. A 1" filter will need to be replaced more often compared to a 4" filter.
- A 1" pleated air filter must be exchanged every 30-60 days.
- A 2" pleated air filter must be replaced every 3 months.
- A 3” pleated air filter ought to be replaced every 4 months.
- A 4" pleated air filter must be exchanged every 6 months.
- A 5” or 6" pleated air filter should be changed out every 9-12 months.
One of the perks of thicker filters is not only do they live longer, but they also provide a better MERV Rating. This means they can do a more effective job of eliminating the particles within your home. They also create less air resistance, which can help ones HVAC system run more efficiently and limit strain on components like the blower motor.
If you own a whole-house air purifier, you will also need 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 have to switch out your air filter more regularly. Pet hair and dander can easily clog an air filter and reduce its effectiveness. For every shedding dog you have, expect to replace the filter a month sooner than you would in a home lacking pets. The same applies to cats, although they don't shed as often as dogs. If you have a hypoallergenic or non-shedding dog or cat, you might not have to switch out your air filter as often.
Even though it's a good rule of thumb, you might want to check on the air filter more frequently to determine if it needs to be exchanged. Dogs don't shed the same amount all year. They shed more in the spring and fall when they are blowing their coat. Check the air filter monthly and exchange it when it seems clogged.
Here are averages that can help you understand 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
- Standard suburban home without pets: every 90 days
- A single dog or cat: every 60 days
- More than one pet or if someone has allergies: 20–45 days