How often you need to replace your air filters may depend on the following:
- Air filter style
- Overall indoor air quality
- Quantity of pets
- Household size
- Air pollution levels and construction surrounding the residence
- The MERV Rating
For common 1"–3" air filters, manufacturers generally ask you to exchange them every 30–90 days. If someone in your family suffers from light to moderate allergies, you could put in a better air filter or replace them even more regularly.
The short answer to "how frequently do I have to change the air filter?":
If there isn't a smoker or pets at home, and your filter is the commonly sold 1" filter with a MERV rating of 4, you should be able to wait up to 90 days before switching it.
What air filter brands survive longer?
Some air filters are manufactured to last up to six months, while others need to be replaced monthly. The larger the air filter, the longer it can last. In most cases, you need to examine the thickness of the filter as opposed to the brand. You also need to check at the MERV Rating.
The MERV Rating is a scale that stretches from 1-20 and calculates how well an air filter will eliminate particles out of the air. The bigger the MERV Rating, the smaller the particle that can be caught by your air filter.
While a filter with a higher MERV Rating can last longer, it might also hamper the circulation in your home. And you will have to change the filter more often. And if you acquire an older system, plan to substitute the filter more frequently to preserve the life of your filter.
How frequently do I have to exchange my air filter based on thickness?
The lifespan of an air filter also hinges on the thickness. A 1" filter will need to be exchanged more frequently versus a 4" filter.
- A 1" pleated air filter ought to be replaced every 30-60 days.
- A 2" pleated air filter should be replaced every 90 days.
- A 3” pleated air filter must be switched every 120 days.
- A 4" pleated air filter should be exchanged every 6 months.
- A 5” or 6" pleated air filter ought to be swapped every 9-12 months.
One of the benefits of denser filters is not only do they last longer, but they also boast a higher MERV Rating. This means they can do a better job of eliminating the particles in your home. They also create less air resistance, which can help ones HVAC system work more proficiently and cut down on wear and tear on components such as the blower motor.
If you want a whole-house air purifier, you will also need to switch out the filters more often.
How often should I exchange my air filter if I have a dog or cat?
If you own pets, you might need to switch out your air filter more regularly. Pet hair and dander can easily clog an air filter and limit its effectiveness. For each shedding dog you want, expect to switch out the filter a month earlier than you would with a home with no pets. The same is true of cats, although they don't shed as often as dogs. If you own a hypoallergenic or non-shedding dog or cat, you might not need to replace your air filter as frequently.
Despite being a good rule of thumb, you might want to examine your air filter more regularly to decide if it needs to be exchanged. Dogs tend not to shed at the same rate year-round. They shed more in the spring and fall when they are blowing their coat. Check the air filter each month and replace it when it seems clogged.
Here are averages that may help you know how regularly you should put in a new air filter at your residence:
- Vacation house or one occupant and no pets or allergies: every 6–12 months
- Ordinary suburban home without pets: every 3 months
- A single dog or cat: every 60 days
- More than one pet or if somebody has allergies: 20–45 days