How regularly you should change the air filters might be on the following:
- Air filter design
- Total indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction nearby the residence
- Your MERV Rating
For standard 1"–3" air filters, manufacturers generally tell you to change 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 change them even more often.
The shortest answer to "how frequently do I need to switch out my air filter?":
If you don't have a smoker or pets in the 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 changing it.
What air filter styles last longer?
A few air filters are manufactured to survive up to six months, while others should be swapped month-to-month. The thicker the air filter, the longer it can last. In most cases, you should look at the thickness of the filter instead of the brand. You also need to look at the MERV Rating.
The MERV Rating is a scale that goes from 1-20 and measures how well an air filter should eliminate particles out of the air. The higher the MERV Rating, the smaller the particle that will be captured by the air filter.
While a filter with a higher MERV Rating can last longer, it might also interfere with the ventilation in your home. And you will have to exchange the filter more regularly. And if you have an older piece of equipment, plan to switch out the filter more regularly to extend the life of your filter.
How frequently should I substitute my air filter based on thickness?
The lifespan of an air filter also relies on the thickness. A 1" filter will need to be swapped out more frequently compared to a 4" filter.
- A 1" pleated air filter ought to be exchanged every 30-60 days.
- A 2" pleated air filter must be replaced every 90 days.
- A 3” pleated air filter ought to be switched every 4 months.
- A 4" pleated air filter must be replaced every 6 months.
- A 5” or 6" pleated air filter must be replaced every 9-12 months.
One of the benefits of thicker filters is not only do they live longer, but they also have a higher MERV Rating. This means they should do a superior job of filtering out the particles inside your home. They also create less air resistance, which can help your HVAC system operate more effectively and cut down on strain on components like the blower motor.
If you have a whole-home air purifier, you will also need to switch out the filters more often.
How frequently should I replace my air filter if I want a dog or cat?
If you have 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 each shedding dog you have, expect to switch out the filter a month sooner than you would in a home without pets. The same goes for cats, although they tend not to shed as much as dogs. If you own a hypoallergenic or non-shedding dog or cat, you might not have to switch out your air filter as often.
Despite being a good rule of thumb, you will need to check your air filter more regularly to decide if it should be swapped out. 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. Take a look at the air filter monthly and replace it when it looks clogged.
Here are averages that may help you recognize 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
- Ordinary suburban home without pets: every 3 months
- One dog or cat: every 2 months
- More than one pet or if someone has allergies: 20–45 days