How Long Does an Air Purifier Filter Last?

The length of time a filter for an air purifier will last can vary from 30 days to 5 years. This will depend on a number of different factors which are discussed below. 

How Long Does an Air Purifier Filter Last

Here are factors affecting how long an air purifier filter lasts. 

What the Filter is Made Of

Air purifiers work by the simple process of a fan drawing room air into the unit, through a filter or series of filters, and back out into the room as purified air. These filters may be made of fiberglass strands, various kinds of treated or untreated paper, carbon fibers or granules, aluminum or plastic fibers.

Each kind will have a different maximum lifespan, as shown below.  Note that longevity is based on continuous or near-continuous use of the air purifier. 

How Long Does an Air Purifier Filter Last – by Type

Filter TypeLongevity
HEPA18-36 months
Media / Paper6-12 months
Electrostatic3-5 years
Fiberglass30-90 days

HEPA Filters are the filters with the best filtering capability, and are able to filter out 99.97% of extremely small particles like smoke, virus, and bacteria. They are made of glass or synthetic fibers which are aligned in such a way that the material is so dense that almost no contaminants can pass through. HEPA filters are usually paired with a “pre-filter” to catch the larger particles, and thus, the HEPA filter can last for 18 months to 3 years.

Media Filters like the Infinity air purifier filter are made of a paper-like material that has many deep pleats to greatly increase the surface area over which the room air passes. This increases the filtering efficiency of a media filter up to seven times over the fiberglass filter when it comes to removing dust and other airborne particles. Because they are made of paper, media filters will only last between 6 months and 1 year. 

Electrostatic Filters are made of a blend of polyurethane and polypropylene fibers plus an aluminum mesh that develop a static charge when air passes through them. The dust, pollen, and other particles stick to the charged fibers and remain trapped until the filter is cleaned. Because this type of filter is waterproof, it can be regularly cleaned with a garden hose every 30 to 90 days and can last 3 to 5 years. 

Fiberglass Filters, which are used widely in home HVAC systems, are used in air purifiers as a “pre-filter” to trap some of the larger airborne particles such as dust and hair. Fiberglass filters are inexpensive and are usually only made to last about 30 to 90 days. Sometimes they can be partially cleaned by blowing or gently tapping over a wastebasket, but work best when simply replaced. 

Air Conditions – How dirty is the air?

We all know that in certain places and at certain times, the quality of the air in our homes can get pretty polluted. Big cities may have a smog problem. Nearby construction may raise tremendous amounts of dust. Heavy smokers may keep the air blue.

Pets – especially certain breeds of dogs – may have you picking and brushing hairs as a normal routine.

With air conditions such as these, air purifier filters can get clogged and need cleaning or replacing even sooner than what is normal. Failure to do so will not only shorten the length of time your air purifier filter will work efficiently, but may also put added strain on the machine itself and result in early failure. 

Air Purifier Brand 

When discussing HEPA air purifier filters, the brand does have some impact on filter longevity. 

How Long Do Air Purifier Filters Last by Brand

BrandAir Purifier Filter Lasts:
Shark18-36 months
Holmes18-30  months
Dyson18-36 months
Kenmore18-24 months
Hunter18-30 months
Honeywell24-36 months
Coway18-30 months
Levoit24-30 months

*These are all HEPA filters

How do you know when your air purifier needs a new filter?

Many air purifiers have built-in technology that senses when the filter needs to be cleaned or changed. There is usually a light or some other signal to alert the user to this condition. But there are also other ways to know that it’s time to change the filter::

  • Unusual sounds coming from the machine – like it’s working too hard.
  • Sniffling, sneezing or an itchy eye condition that is unusual for someone in the house.
  • Excessive dust appearing on surfaces that isn’t normal.
  • Overheated air purifier. 

How often do I change HEPA filters in an air purifier?

As mentioned above, in ideal conditions, a HEPA filter can last 2 to 3 years with proper care. But this will depend on regular care, which includes changing any pre-filter before it gets too clogged. The actual schedule for changing a HEPA filter should be given in the owner’s manual of your particular machine. It should also be printed clearly on the packaging in which the filter arrives – anywhere from 6 to 18 months. 

Air Purifier Filter FAQs 

How do I know if my HEPA filter is dirty?

Here is how to tell if your HEPA filter is dirty:

  • It looks dirty – A layer of dirt and debris is covering it
  • The machine is “wheezing,” like it is having a hard time getting air through it
  • A dirty or musty smell is coming from the machine
  • The air purifier is unusually warm
  • Your allergies are worse
  • A “Dirty Filter” notification message or light is on 

Can you wash air purifier filters and reuse them?

The only air purifier filters that are designed to be washed and reused are the electrostatic filters, often marketed as “permanent filters”. They are made of waterproof materials that will continue to perform their function after being cleaned according to the manufacturer’s instructions. 

All filters made with paper will be negatively affected by water. HEPA filters especially, which are designed to filter out invisible particles, will no longer be able to provide the level of air quality that is expected of them if washed.  

Written by

Rene has worked 10 years in the HVAC field and now is the Senior Comfort Specialist for PICKHVAC. He holds an HVAC associate degree and EPA & R-410A Certifications. Protection Status