There are two methods to calculate how long a HEPA filter lasts. One is to do real-world tests in a representative environment of where the HEPA filter will be used. The other is to use the ‘CCM’ method.
For real world tests at Smart Air, we run each of air purifiers in real-world air in Beijing, China for a period of months (100-200 days). We then test the HEPA efficiency on a daily or weekly basis, and calculate the drop in effectiveness over time. For more information on this testing method, see our article on the Sqair HEPA filter’s lifespan.
The CCM method makes use of the GB18801 air purifier standard. A HEPA filter is subjected to large amounts of PM2.5, then continually tested until the air purifier’s CADR drops by 50%. This is then considered the ‘time’ to replace your HEPA filter.
When Should Change My HEPA Filter?
In reality, everybody’s air purifier usage is different, and the amount of pollution in the air changed depending on where you live. That’s why we’ve created a handy tool to know when to change your HEPA filter.