How frequently you have to replace your air filters might be on the following:
- Air filter model
- Total indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the residence
- The MERV Rating
For basic 1"–3" air filters, manufacturers typically instruct you to exchange them every 30–90 days. If you suffer from mild to moderate allergies, you could install a better air filter or replace them even more regularly.
The shortest answer to "how frequently do I have to change the air filter?":
If you don't have a smoker or pets in your 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 designed to last up to six months, while others need to be replaced month-to-month. The thicker the air filter, the longer it can last. Generally, you can examine the thickness of the filter rather than the brand. You also need to check at the MERV Rating.
The MERV Rating is a scale that records from 1-20 and calculates how well an air filter can pull particles from the air. The bigger the MERV Rating, the smaller the particle that can be captured by the air filter.
While a filter with a higher MERV Rating will last longer, it might also restrict the flow of air in your home. And you will have to replace the filter more often. And if you own an older system, plan to replace the filter more regularly to maintain the quality of your filter.
How regularly should I replace my air filter based on thickness?
The lifespan of an air filter also depends on its thickness. A 1" filter will have to be exchanged more frequently instead of a 4" filter.
- A 1" pleated air filter must be changed out every 30-60 days.
- A 2" pleated air filter should be switched every 90 days.
- A 3” pleated air filter ought to be switched every 120 days.
- A 4" pleated air filter should be swapped out every 6 months.
- A 5” or 6" pleated air filter ought to be changed out every 9-12 months.
One of the advantages of denser filters is not only do they survive longer, but they also boast a higher MERV Rating. This means they can do a superior job of eliminating the particles in your home. They also produce less air resistance, which can help your HVAC system function more proficiently and reduce strain on components including the blower motor.
If you want a whole-house air purifier, you will also have to replace the filters more regularly.
How frequently should I replace my air filter if I own a dog or cat?
If you have pets, you might need to switch out your air filter more frequently. Pet hair and dander can rapidly clog an air filter and minimize its effectiveness. For every shedding dog you own, expect to change out the filter a month sooner than you would for a home without 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 have to replace your air filter as frequently.
Even though it's a good rule of thumb, you might want to check on the air filter more frequently to decide if it needs to be exchanged. Dogs usually do not shed the same amount year-round. They shed more in the spring and fall when they are blowing their coat. Take a look at the air filter each month and replace it when it appears clogged.
Here are averages that might help you know how frequently you should install a new air filter at your residence:
- Vacation house or an individual occupant and no pets or allergies: every 6–12 months
- Standard suburban home without pets: every 3 months
- A single dog or cat: every 60 days
- More than one pet or if anyone has allergies: 20–45 days