How frequently you have to exchange the air filters may be on the following:
- Air filter model
- Total indoor air quality
- Quantity of pets
- Household size
- Air pollution levels and construction around the residence
- The MERV Rating
For common 1"–3" air filters, manufacturers normally ask you to exchange 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 regularly.
The short answer to "how often do I need to switch out the 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 prior to switching it.
What air filter types last longer?
Many air filters are designed to survive up to six months, while others have to be changed each month. The denser the air filter, the longer it should last. Generally, you need to check the thickness of the filter rather than the brand. You also need to look at the MERV Rating.
The MERV Rating is a scale that goes from 1-20 and assesses how well an air filter will eliminate particles out of the air. The higher the MERV Rating, the smaller the particle that can be caught by the air filter.
While a filter with a higher MERV Rating might last longer, it might also interfere with the ventilation in your home. And you will have to replace the filter more regularly. And if you acquire an older system, plan to change the filter more regularly to conserve the quality of your filter.
How regularly do I need to exchange my air filter based on thickness?
The lifespan of an air filter also depends on its thickness. A 1" filter will need to be changed out more often versus a 4" filter.
- A 1" pleated air filter must be replaced every 30-60 days.
- A 2" pleated air filter should be replaced every 90 days.
- A 3” pleated air filter must be switched every 4 months.
- A 4" pleated air filter ought to be swapped out every 6 months.
- A 5” or 6" pleated air filter ought to be replaced every 9-12 months.
One of the perks of thicker filters is not only do they survive longer, but they also provide a better MERV Rating. This means they should do a more effective job of getting rid of the particles in your home. They also generate less air resistance, which can help an HVAC system work more proficiently and cut down on strain on components including the blower motor.
If you have a whole-home air purifier, you will also have to replace the filters more regularly.
How frequently should I exchange my air filter if I have a dog or cat?
If you want pets, you might need to replace your air filter more frequently. 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 for a home without pets. The same is true of cats, although they tend not to shed as heavily as dogs. If you want a hypoallergenic or non-shedding dog or cat, you might not need to replace your air filter as frequently.
Even though it's a good rule of thumb, you might want to check on your air filter more often to see if it has to be exchanged. 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. Inspect the air filter monthly and replace it when it seems clogged.
Here are averages that might help you understand 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 3 months
- A single dog or cat: every 2 months
- More than one pet or if anyone has allergies: 20–45 days