HEPA Lifespan Test Method<\/h2>\nGus turns on the Original DIY<\/a>\u00a0while he sleeps each night and tracks effectiveness using a Dylos particle counter<\/a>. I calculate effectiveness as the percentage decrease in the number of particles .5 microns (and above) over the course of the night.\n\nHere\u2019s what a normal day looks like:\n\n![\"HEPA](\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2014\/11\/HEPA-Longevity-200-Day-Test-Sample-Example-Day.jpg\")
\n\nTo smooth out variability over time, I averaged the effectiveness over every 10 days. For the full details on the methods, check out my earlier post<\/a>.\nHEPA Lifespan Results<\/h2>\nThe death crawl continues. At Day 200, effectiveness dipped to just below 50%.\n\n\n![\"HEPA](\"https:\/\/smartairfilters.com\/wordpress\/wp-content\/uploads\/2021\/04\/DIY-1.0-Longevity-Test-Graph-200-Days-1024x768.jpg\")
<\/figure>\n\n\nAt the risk of Gus\u2019s health (especially given the coming onslaught of winter air<\/a>), I voted for Gus to stop the test. So the test is over!\nConclusion<\/h2>\nIn real Beijing air, the Smart Air HEPA effectiveness decreased by about 20% after 150 days (1,109 hours), which is when I would change the filter.\n\nBottom Line<\/div>Bottom Line:<\/div>I recommend changing the HEPA every 150 days at about 8 hours a day or approximately every 1,000 hours. You can adjust the number based on how many hours you use it per day.<\/div>Smart Air<\/div><\/div>\n\nLimitations:\u00a0<\/strong>We did the test in Beijing, so HEPAs probably last a few more weeks in places with cleaner air (but still not “clean” air) like Guangzhou and Hong Kong.\n\nRead more:<\/strong> Check out how the real-world Sqair HEPA longevity test<\/a> compared to official lab tests.\nOpen Data<\/h3>\nAs always, I\u2019m publishing the raw data<\/a>\u2013all 200 days!","protected":false},"excerpt":{"rendered":"One of the biggest questions when I started doing the DIY was HEPA lifespan–how long do the HEPAs last? Rather than just give people a nice-sounding answer, I wanted to see what the data says, so Gus has been dutifully turning on his Original DIY\u00a0every day in his 12.3m2 Beijing … <\/p>\n
<\/figure>\n\n\nAt the risk of Gus\u2019s health (especially given the coming onslaught of winter air<\/a>), I voted for Gus to stop the test. So the test is over!\nConclusion<\/h2>\nIn real Beijing air, the Smart Air HEPA effectiveness decreased by about 20% after 150 days (1,109 hours), which is when I would change the filter.\n\nBottom Line<\/div>Bottom Line:<\/div>I recommend changing the HEPA every 150 days at about 8 hours a day or approximately every 1,000 hours. You can adjust the number based on how many hours you use it per day.<\/div>Smart Air<\/div><\/div>\n\nLimitations:\u00a0<\/strong>We did the test in Beijing, so HEPAs probably last a few more weeks in places with cleaner air (but still not “clean” air) like Guangzhou and Hong Kong.\n\nRead more:<\/strong> Check out how the real-world Sqair HEPA longevity test<\/a> compared to official lab tests.\nOpen Data<\/h3>\nAs always, I\u2019m publishing the raw data<\/a>\u2013all 200 days!","protected":false},"excerpt":{"rendered":"One of the biggest questions when I started doing the DIY was HEPA lifespan–how long do the HEPAs last? Rather than just give people a nice-sounding answer, I wanted to see what the data says, so Gus has been dutifully turning on his Original DIY\u00a0every day in his 12.3m2 Beijing … <\/p>\n
Bottom Line<\/div>
Bottom Line:<\/div>
I recommend changing the HEPA every 150 days at about 8 hours a day or approximately every 1,000 hours. You can adjust the number based on how many hours you use it per day.<\/div>
Smart Air<\/div><\/div>\n\nLimitations:\u00a0<\/strong>We did the test in Beijing, so HEPAs probably last a few more weeks in places with cleaner air (but still not “clean” air) like Guangzhou and Hong Kong.\n\nRead more:<\/strong> Check out how the real-world Sqair HEPA longevity test<\/a> compared to official lab tests.\nOpen Data<\/h3>\nAs always, I\u2019m publishing the raw data<\/a>\u2013all 200 days!","protected":false},"excerpt":{"rendered":"