How regularly you need to change your air filters can be on the following:
- Air filter design
- Overall indoor air quality
- Quantity of pets
- Household size
- Air pollution levels and construction nearby the residence
- The MERV Rating
For common 1"–3" air filters, manufacturers typically tell you to exchange them every 30–90 days. If you suffer from mild to moderate allergies, you could install a better air filter or change them even more regularly.
The shortest answer to "how frequently do I need to exchange 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 prior to replacing it.
What air filter types last longer?
A few air filters are supposed to last up to six months, while others need to be replaced monthly. The larger the air filter, the longer it will last. In most cases, you need to check the thickness of the filter versus the brand. You also need to check at the MERV Rating.
The MERV Rating is a scale that goes from 1-20 and calculates how efficiently an air filter can pull particles out of 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 should last longer, it may also restrict the ventilation in your home. And you will need to change the filter more regularly. And if you acquire an older piece of equipment, plan to exchange the filter more often to extend the life of your filter.
How often do I have to replace my air filter based on thickness?
The lifespan of an air filter also depends on the thickness. A 1" filter will have to be exchanged more often compared to a 4" filter.
- A 1" pleated air filter must be changed every 30-60 days.
- A 2" pleated air filter ought to be exchanged every 90 days.
- A 3” pleated air filter should be changed out 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 replaced every 9-12 months.
One of the advantages of thicker filters is not only do they live longer, but they also posses a better MERV Rating. This means they will do a better job of filtering out the particles inside your home. They also create less air resistance, which can help ones HVAC system function more proficiently and cut down on strain on components including the blower motor.
If you have a whole-house air purifier, you will also have to exchange the filters more regularly.
How regularly should I replace my air filter if I have a dog or cat?
If you own pets, you might have to change out your air filter more frequently. Pet hair and dander can easily clog an air filter and reduce its effectiveness. For every shedding dog you want, expect to switch out the filter a month earlier than you would for a home without pets. The same is true of cats, although they tend not to shed as heavily as dogs. If you have a hypoallergenic or non-shedding dog or cat, you might not need to exchange your air filter as frequently.
Despite being a good rule of thumb, you will need to check the air filter more often to decide if it has to be exchanged. Dogs tend not to shed the same amount all year. They shed more in the spring and fall when they are blowing their coat. Inspect the air filter monthly and exchange it when it seems 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 a single occupant and no pets or allergies: every 6–12 months
- Standard suburban home without pets: every 3 months
- A single dog or cat: every 2 months
- More than one pet or if anyone has allergies: 20–45 days