How frequently you have to exchange the air filters may be on the following:
- Air filter type
- Overall indoor air quality
- Number of pets
- Household size
- Air pollution levels and construction near the residence
- The MERV Rating
For common 1"–3" air filters, manufacturers usually ask you to swap them every 30–90 days. If someone in your family suffers from light to moderate allergies, you can use a better air filter or replace them even more frequently.
The short answer to "how frequently should I replace my air filter?":
If you don't have a smoker or pets in your 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 prior to replacing it.
What air filter styles last longer?
Many air filters are designed to survive up to six months, while others should be exchanged monthly. The denser the air filter, the longer it will last. Overall, you can check the thickness of the filter versus 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 assesses how effectively an air filter should eliminate particles out of the air. The bigger the MERV Rating, the smaller the particle that can be captured by your air filter.
While a filter with a higher MERV Rating can last longer, it may also impede the circulation in your home. And you will have to switch out the filter more often. And if you acquire an older piece of equipment, plan to replace the filter more often to maintain the life of your filter.
How regularly do I have to switch out my air filter based on thickness?
The lifespan of an air filter also hinges on its thickness. A 1" filter will have to be replaced more frequently instead of 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 must be replaced every 4 months.
- A 4" pleated air filter ought to be replaced every 6 months.
- A 5” or 6" pleated air filter should be swapped every 9-12 months.
One of the benefits of thicker filters is not only do they survive longer, but they also boast a higher MERV Rating. This means they should do a better job of getting rid of the particles inside your home. They also create less air resistance, which can help an HVAC system operate more proficiently and cut down on wear and tear on components such as the blower motor.
If you want a whole-home air purifier, you will also need to switch out the filters more regularly.
How frequently should I change my air filter if I have a dog or cat?
If you own pets, you might need to switch out your air filter more often. Pet hair and dander can rapidly clog an air filter and limit its effectiveness. For every shedding dog you want, expect to change out the filter a month sooner than you would in a home lacking pets. The same goes for 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 have to change out your air filter as often.
Although a good rule of thumb, you might want to check on your air filter more frequently to decide if it needs to be swapped out. Dogs tend not to shed the same amount all year. They shed more in the spring and fall when they are blowing their coat. Check the air filter monthly and exchange it when it seems clogged.
Here are averages that might help you learn how regularly you should get a new air filter at your residence:
- Vacation house or one occupant and no pets or allergies: every 6–12 months
- Average suburban home without pets: every 90 days
- A single dog or cat: every 60 days
- More than one pet or if anyone has allergies: 20–45 days