How frequently you should replace the air filters may depend on the following:
- Air filter design
- 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 typically ask 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 change them even more often.
The quick answer to "how frequently should I swap my air filter?":
If there isn't a smoker or pets in the home, and the filter is the often 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 models last longer?
Some air filters are supposed to last up to six months, while others need to be exchanged monthly. The thicker the air filter, the longer it can last. Overall, you can check the thickness of the filter rather than 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 efficiently an air filter should remove particles out of the air. The better the MERV Rating, the smaller the particle that will be captured by your air filter.
While a filter with a higher MERV Rating should last longer, it may also hamper the circulation in your home. And you will have to change the filter more frequently. And if you acquire an older piece of equipment, plan to substitute the filter more regularly to extend the quality of your filter.
How regularly do I need to substitute my air filter based on thickness?
The longevity of an air filter also counts on its thickness. A 1" filter will need to be exchanged more frequently compared to a 4" filter.
- A 1" pleated air filter ought to be replaced every 30-60 days.
- A 2" pleated air filter must be replaced every 3 months.
- A 3” pleated air filter should be replaced every 4 months.
- A 4" pleated air filter ought to be changed out every 6 months.
- A 5” or 6" pleated air filter must be swapped every 9-12 months.
One of the advantages of thicker filters is not only do they last longer, but they also posses a better MERV Rating. This means they can do a superior job of eliminating the particles within your home. They also generate less air resistance, which can help an HVAC system function more effectively and decrease wear and tear on components such as the blower motor.
If you own a whole-house air purifier, you will also have to switch out the filters more often.
How frequently should I exchange my air filter if I own a dog or cat?
If you want pets, you might need to switch out your air filter more often. Pet hair and dander can quickly clog an air filter and minimize its effectiveness. For every shedding dog you have, expect to switch out the filter a month sooner than you would in a home lacking pets. The same applies to cats, although they usually do not shed as much as dogs. If you own a hypoallergenic or non-shedding dog or cat, you might not need to change out your air filter as frequently.
Although a good rule of thumb, you might want to check on your air filter more regularly to decide if it needs to be replaced. Dogs usually do not shed the same amount year-round. They shed more in the spring and fall when they are blowing their coat. Inspect the air filter monthly and exchange it when it appears clogged.
Here are averages that can help you learn how frequently 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
- Common suburban home without pets: every 90 days
- One dog or cat: every 2 months
- More than one pet or if somebody has allergies: 20–45 days