{"id":786,"date":"2013-07-20T17:41:18","date_gmt":"2013-07-20T09:41:18","guid":{"rendered":"http:\/\/smartairfilters.com\/cn\/?p=786"},"modified":"2020-07-15T11:56:20","modified_gmt":"2020-07-15T03:56:20","slug":"diy-filter-compared","status":"publish","type":"post","link":"https:\/\/smartairfilters.com\/en\/blog\/diy-filter-compared\/","title":{"rendered":"DIY Filter Compared to Expensive Filters"},"content":{"rendered":"

UPDATE:\u00a0I now have directly comparable data with the DIY Filter, Blue Air, and Philips: <\/strong>Direct comparison tests<\/strong><\/a>.<\/strong><\/p>\n

In earlier posts (1<\/a>, 2<\/a>), I showed that you can make effective an DIY filter to clean air pollution out of your home. But just because it is effective doesn\u2019t mean it\u2019s as effective<\/strong> as the Ferrari filters.\u00a0How effective is the DIY filter compared to the expensive filters?<\/p>\n

I\u2019ll attempt to answer this question from several angles in different posts.<\/p>\n

 <\/p>\n

Comparison with Dr. Saint Cyr’s Test<\/strong><\/p>\n

Here\u2019s one method: comparisons with the published data from the blog of the Beijing doctor Dr. Saint Cyr<\/a> (which was an original inspiration for me that air purifiers could actually reduce air pollution). He ran tests of an 11,000 RMB IQ Air and a 6,000 RMB Blue Air. I used the same calculation of effectiveness and compared his results for the pricey machines with tests of my DIY filter. Here are the results:<\/p>\n

\"DIY<\/p>\n

To make the comparisons more precise, I compared my filter results only to the tests he reports from the IQ Air and Blue Air on max power<\/strong> in his smaller room.<\/p>\n

Dr. Saint Cyr calculated reductions based on\u00a0outside\u00a0<\/strong>air quality, which I do not think is the best method. I think it makes more sense to calculate reductions based on the room air before and after using the filter because my room air is significantly cleaner than outside air, even before using the filter. But to make the data comparable, I calculated effectiveness using Dr. Saint Cyr\u2019s method.<\/em><\/p>\n

Now, the comparisons aren\u2019t perfect. Dr. Saint Cyr\u2019s smaller room is still 6.5 meters larger than mine. He also doesn\u2019t say how long he ran his filters and whether the doors were closed. My tests were with the doors closed and overnight, so the filter had several hours to run.<\/p>\n

(Update: via email Dr. Saint Cyr said his tests were with doors closed and testing times of 1 hour+.)<\/p>\n

But even if the difference in room size bumps mine down 5% and the others up 5%, that would mean 11,000 RMB and 166 RMB get you similar results. To illustrate that, I calculated a graph of how much you\u2019re paying for each percentage reduction in air pollution:<\/p>\n

\"DIY<\/p>\n

Of course, the ideal test would use all three filters in the same room with the same particle counter. To that end, I will hopefully get the chance to borrow a friend\u2019s Panasonic filter and test it in my home. I\u2019ll post those results when I get them.<\/p>\n

 <\/p>\n

Conclusion: A DIY Filter can be as effective<\/h3>\n

Although the comparisons are imperfect, they show that a DIY filter is at least roughly comparable to expensive filters at a far lower cost. This illustrates my larger point: all you really need to combat particulate air pollution is a HEPA filter<\/strong>. In fact, Dr. Saint Cyr found the same thing<\/a> in his tests of a much simpler Hunter brand HEPA filter. In a room with the doors closed, his HEPA got 91% of the pollution\u2013similar to what I found.<\/p>\n

For data nerds like me, I\u2019m posting more details on my data and methods here:<\/p>\n

Test Details:<\/strong><\/p>\n

<\/p>\n

For Dr. Saint Cyr\u2019s data, I used only the data from his smaller room (the bedroom) for the Blue Air and IQ Air on max power. I chose the max power only because I run my filter on its highest setting (3 out of 3).<\/p>\n

Here\u2019s my original data:<\/p>\n

\"DIY<\/p>\n

The data are from hourly PM2.5 measurements of my particle counter<\/a> at the start in the evening to when I wake up in the morning. All tests were in my bedroom with the door and windows closed (size 13.5 meters squared). To make my measurements comparable with Dr. Saint Cyr, I calculated percent reduction from outside air.<\/p>\n

For outside AQI, I used the US Embassy Twitter feed<\/a> at the time my test started and converted it into a count on my particle counter. This is a bit complicated because my counter gives the number\u00a0<\/strong>of particles, and the US Embassy estimates the\u00a0weight\u00a0<\/strong>of those particles. To calculate between the two, I\u2019ve taken 36 measurements with my particle counter outside and compared them to US Embassy concentrations. Overall, they correlate at r = .90, which is about as good as you could expect given that their site is in the northeast part of town, and I\u2019m in Dongcheng, near the Drum Tower.<\/p>\n

Here\u2019s a graph comparing\u00a0US Embassy PM2.5 concentrations with\u00a0measurements of outside air from my particle counter:<\/p>\n

\"DIY<\/p>\n

(Update: Newer tests comparing my particle counter to the US embassy machine here<\/a>.)<\/p>","protected":false},"excerpt":{"rendered":"

UPDATE:\u00a0I now have directly comparable data with the DIY Filter, Blue Air, and Philips: Direct comparison tests. In earlier posts (1, 2), I showed that you can make effective an DIY filter to clean air pollution out of your home. But just because it is effective doesn\u2019t mean it\u2019s as … <\/p>\n

Read more<\/a><\/p>\n","protected":false},"author":1035,"featured_media":3652,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_relevanssi_hide_post":"","_relevanssi_hide_content":"","_relevanssi_pin_for_all":"","_relevanssi_pin_keywords":"","_relevanssi_unpin_keywords":"","_relevanssi_related_keywords":"","_relevanssi_related_include_ids":"","_relevanssi_related_exclude_ids":"","_relevanssi_related_no_append":"","_relevanssi_related_not_related":"","_relevanssi_related_posts":"","_relevanssi_noindex_reason":"","footnotes":""},"categories":[259,262],"tags":[81,89],"class_list":["post-786","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-filters","category-reviews","tag-big-brand-air-filters","tag-comparison","resize-featured-image"],"acf":[],"_links":{"self":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts\/786","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/users\/1035"}],"replies":[{"embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/comments?post=786"}],"version-history":[{"count":5,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts\/786\/revisions"}],"predecessor-version":[{"id":11472,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/posts\/786\/revisions\/11472"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/media\/3652"}],"wp:attachment":[{"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/media?parent=786"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/categories?post=786"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/smartairfilters.com\/en\/wp-json\/wp\/v2\/tags?post=786"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}