How regularly you have to exchange the air filters may depend on the following:
- Air filter design
- Total indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction near the residence
- The MERV Rating
For standard 1"–3" air filters, manufacturers normally ask you to change them every 30–90 days. If you suffer from light to moderate allergies, you can put in a better air filter or exchange them even more frequently.
The short answer to "how often should I replace the air filter?":
If you don't have a smoker or pets in the 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 changing it.
What air filter models survive longer?
Many air filters are manufactured to last up to six months, while others should be switched monthly. The thicker the air filter, the longer it can last. Generally, you need to examine the thickness of the filter versus the brand. You also need to consider at the MERV Rating.
The MERV Rating is a scale that goes from 1-20 and assesses how effectively an air filter should remove particles from the air. The better the MERV Rating, the smaller the particle that can be caught by the air filter.
While a filter with a higher MERV Rating will last longer, it may also impede the circulation in your home. And you will need to replace the filter more regularly. And if you have an older piece of equipment, plan to substitute the filter more frequently to maintain the life of your filter.
How frequently should I substitute 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 frequently compared to a 4" filter.
- A 1" pleated air filter ought to be changed out every 30-60 days.
- A 2" pleated air filter must be swapped out every 90 days.
- A 3” pleated air filter ought to be exchanged every 120 days.
- A 4" pleated air filter should be replaced 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 last longer, but they also boast a better MERV Rating. This means they will do a superior job of eliminating the particles in your home. They also generate less air resistance, which can help an HVAC system operate more efficiently and limit wear and tear on components like the blower motor.
If you own a whole-house air purifier, you will also need to exchange the filters more frequently.
How regularly should I change my air filter if I want a dog or cat?
If you have pets, you might need to change out your air filter more frequently. Pet hair and dander can quickly clog an air filter and minimize its effectiveness. For each shedding dog you own, expect to change out the filter a month sooner than you would with a home lacking pets. The same is true of cats, although they don't shed as heavily as dogs. If you want a hypoallergenic or non-shedding dog or cat, you might not need to replace your air filter as often.
Even though it's a good rule of thumb, you will need to check on the air filter more frequently to see if it should be swapped out. Dogs tend not to shed at the same rate 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 looks clogged.
Here are averages that can help you know how regularly you should get 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 90 days
- One dog or cat: every 60 days
- More than one pet or if anyone has allergies: 20–45 days