How regularly you need to replace your air filters may depend on the following:
- Air filter style
- Total indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction around the residence
- Your MERV Rating
For standard 1"–3" air filters, companies generally instruct you to swap them every 30–90 days. If someone in your family suffers from mild to moderate allergies, you could put in a better air filter or replace them even more frequently.
The quick answer to "how often do I need to change the air filter?":
If there isn't 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 prior to changing it.
What air filter styles last longer?
A few air filters are supposed to last up to six months, while others need to be replaced month-to-month. The denser the air filter, the longer it should last. Generally, you need to examine the thickness of the filter versus 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 efficiently an air filter should pull particles from the air. The higher the MERV Rating, the smaller the particle that could be captured by the air filter.
While a filter with a higher MERV Rating should last longer, it can also hamper the flow of air in your home. And you will need to replace the filter more frequently. And if you own an older system, plan to switch out the filter more regularly to maintain the quality of your filter.
How often do I have to exchange my air filter based on thickness?
The lifespan of an air filter also counts on the thickness. A 1" filter will have to be changed out more frequently compared to a 4" filter.
- A 1" pleated air filter should be replaced every 30-60 days.
- A 2" pleated air filter ought to be replaced every 3 months.
- A 3” pleated air filter should be exchanged every 120 days.
- A 4" pleated air filter must be exchanged every 6 months.
- A 5” or 6" pleated air filter should be changed out every 9-12 months.
One of the perks of thicker filters is not only do they live longer, but they also posses a higher MERV Rating. This means they can do a superior job of filtering out the particles in your home. They also produce less air resistance, which can help your HVAC system run more effectively and reduce wear and tear on components like the blower motor.
If you want a whole-house air purifier, you will also have to switch out the filters more often.
How often should I exchange my air filter if I own a dog or cat?
If you have pets, you might need to change out your air filter more regularly. Pet hair and dander can rapidly clog an air filter and minimize its effectiveness. For every shedding dog you want, expect to exchange the filter a month earlier than you would with a home without pets. The same goes for 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 change out your air filter as often.
Although a good rule of thumb, you might want to check the air filter more often to figure out if it should be exchanged. Dogs usually do not shed at the same rate all year. They shed more in the spring and fall when they are blowing their coat. Inspect the air filter monthly and change it when it looks clogged.
Here are averages that might help you understand how often 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 90 days
- A single dog or cat: every 60 days
- More than one pet or if somebody has allergies: 20–45 days