How often you need to replace your air filters might be on the following:
- Air filter type
- Total indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction nearby the residence
- Your MERV Rating
For common 1"–3" air filters, brands normally tell you to change them every 30–90 days. If someone in your family suffers from light to moderate allergies, you could install a better air filter or exchange them even more frequently.
The short answer to "how often do I have to exchange the 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 prior to changing it.
What air filter types last longer?
A few air filters are supposed to survive up to six months, while others should be exchanged monthly. The thicker the air filter, the longer it can last. Generally, you should examine the thickness of the filter instead of the brand. You also need to take a look at the MERV Rating.
The MERV Rating is a scale that stretches from 1-20 and calculates how effectively an air filter can eliminate particles out of the air. The higher the MERV Rating, the smaller the particle that will be caught by your air filter.
While a filter with a higher MERV Rating might last longer, it could also impede the airflow in your home. And you will have to exchange the filter more frequently. And if you own an older system, plan to switch out the filter more regularly to maintain the life of your filter.
How frequently do I have to substitute my air filter based on thickness?
The longevity of an air filter also hinges on the thickness. A 1" filter will have to be changed out more often than a 4" filter.
- A 1" pleated air filter should be changed every 30-60 days.
- A 2" pleated air filter must be replaced every 90 days.
- A 3” pleated air filter ought to be exchanged every 4 months.
- A 4" pleated air filter should be exchanged every 6 months.
- A 5” or 6" pleated air filter must be replaced every 9-12 months.
One of the perks of denser filters is not only do they survive longer, but they also have a higher MERV Rating. This means they should do a better job of getting rid of the particles inside your home. They also produce less air resistance, which can help ones HVAC system function more efficiently and limit wear and tear on components like the blower motor.
If you want a whole-home air purifier, you will also need to exchange the filters more regularly.
How frequently should I exchange my air filter if I own a dog or cat?
If you own pets, you might need to replace your air filter more frequently. Pet hair and dander can rapidly clog an air filter and minimize its effectiveness. For each shedding dog you want, expect to change out the filter a month sooner than you would for a home without pets. The same goes for cats, although they usually do not shed as much as dogs. If you want a hypoallergenic or non-shedding dog or cat, you might not have to replace your air filter as often.
Despite being a good rule of thumb, you might want to check the air filter more frequently to determine if it needs to be swapped out. Dogs usually do not shed the same amount all year. 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 appears clogged.
Here are averages that might help you understand how regularly you should put in 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 90 days
- A single dog or cat: every 2 months
- More than one pet or if somebody has allergies: 20–45 days