How regularly you need to exchange your air filters could be on the following:
- Air filter style
- Overall indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction near the residence
- Your MERV Rating
For standard 1"–3" air filters, manufacturers usually tell you to exchange them every 30–90 days. If someone in your family suffers from mild to moderate allergies, you could put in a better air filter or replace them even more frequently.
The shortest answer to "how often do I have to exchange my air filter?":
If there isn't a smoker or pets at home, and your filter is the often 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 styles last longer?
Some air filters are supposed to last up to six months, while others should be changed month-to-month. The thicker the air filter, the longer it can last. In general, you should 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 stretches from 1-20 and assesses how efficiently an air filter should remove particles from 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 can also impede the circulation in your home. And you will have to replace the filter more often. And if you own an older system, plan to switch out the filter more often to extend the quality of your filter.
How regularly do I have to switch out my air filter based on thickness?
The lifespan of an air filter also depends on its thickness. A 1" filter will have to be replaced more frequently compared to a 4" filter.
- A 1" pleated air filter ought to be changed every 30-60 days.
- A 2" pleated air filter ought to be switched every 3 months.
- A 3” pleated air filter must 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 survive longer, but they also posses a higher MERV Rating. This means they will do a superior job of filtering out the particles within your home. They also generate less air resistance, which can help an HVAC system function more effectively and decrease wear and tear on components including the blower motor.
If you want a whole-house air purifier, you will also need to exchange the filters more often.
How frequently should I change my air filter if I own a dog or cat?
If you own pets, you might need to switch out your air filter more often. Pet hair and dander can rapidly clog an air filter and limit its effectiveness. For every shedding dog you want, expect to exchange the filter a month earlier than you would in a home with no 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 frequently.
Although a good rule of thumb, you will need to examine the air filter more often to see if it needs 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. Take a look at the air filter monthly and exchange it when it looks clogged.
Here are averages that might help you recognize how regularly you should install 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
- One dog or cat: every 60 days
- More than one pet or if anyone has allergies: 20–45 days