HEPA滤网能清洗吗?

 

HEPA滤网很棒。是PM2.5杀手。

 

 

它们的效率经过多次测试的验证相当便宜;HEPA净化器耗电量和一个灯泡一样少;还有被验证过的医疗作用。唯一的一个困扰:用了几个月后必须把它扔了。

 

如果HEPA能重复使用的话,那该多好啊!在Quora上也有许多人在讨论如何长期使用HEPA。有人说你能直接把灰尘从HEPA“打”出来:

 

 

也有人说能用吸尘机…

 

 

也有的说HEPA能用水洗…但我也看到有人说HEPA千万不能洗。

 

 

如果有人问我HEPA到底能不能清洗或拿吸尘机吸。我的答案只是个简单的“不行”,因为(1)理论上是不可能的(2)HEPA厂家是这么说的。

但身为学霸,这些辩论和理论都没有什么用,我想用数据说话,所以我让Smart Air的工程师CK做了测试!

 

 

这是他的故事:

吸尘器吸HEPA

 

首先,我从实验室里拿了个脏HEPA,测一遍,吸一遍,再测一遍。多亏了Smart Air热情的志愿者,Smart Air的实验室里有无数的脏HEPA。这些HEPA被使用过2-4个月不等。我用了8个不同的脏滤网做了同样的测试。

由左至右的是我吸之前,吸的时候和吸过后的照片。看起来相差不大。

 

 

测试效率

 

我用了三个指标来测HEPA的效果。

颗粒捕捉:我在吸之前和之后测量了HEPA捕捉0.3微米颗粒的效率。用0.3微米是因为0.3微米的颗粒是最难被捕捉的颗粒

出风量:我也测量了吸之前和之后的出风量。

CADR: 我用了颗粒效果和风量数据算出整体效果(CADR)。

 

吸过后的结果

 

平均来说,CADR提高了10%。但是,它们的变量特别大:14% 的增长至3% 的下降。这样的数据,我觉得吸HEPA 或许会稍微提升效率,也很有可能没有提升,甚至将效率拉低!

 

吸尘器对HEPA 做了什么?

 

吸尘器好像把HEPA的纤维拉出来了:

 

 

结论:用吸尘器吸HEPA 或许会有点好处,但这效益不大,而把HEPA 损坏的可能性也存在。所以,我们不建议用吸尘器吸HEPA。

清洗HEPA

 

要是清洗它们的话呢?我把3个HEPA放在花洒下。我在清洗之前做了同样的颗粒和风速测试。清洗之后我等了一天的时间,让它晾干然后做了第二次测试。

 

 

清洗之后的结果

 

我做了3个测试之后就不测了,因为结果特别的明显:清洗之后的HEPA 的效率下降了32%。

 

 

为什么不能清洗?

 

效率为什么下降那么多?首先,清洗之后,风量提高了:

 

 

不错!现在风量更大。

等等,风量怎么提高的?因为颗粒效果降低了:

 

 

清洗好像是损坏了HEPA结构。

结论:吸HEPA 会提升效果,但这效果不大,又有可能损坏HEPA。清洗HEPA就更不用说了,清洗会让效果降低。

根据这些数据,我们还是建议每140天换一次HEPA滤网。

 

公开数据

 

跟之前一样,为了其他书呆子同胞们,原始数据都是公开的。还有测试方法的细节和更多的分析。

想知道压缩空气是否能够用来清洗HEPA?我在Quora上也讨论了这个问题。

祝你呼吸安全的空气!

Choon Khin is a Smart Air engineer from Singapore, studying chemical engineering at the National University of Singapore

在 “HEPA滤网能清洗吗?” 上有 3 条评论

  1. Hi there,

    There are some questions that I hope could be clarify a bit more:
    1. How do you vacuum the HEPA filter, and which side of the filter do you vacuum?
    2. I do not by any means say that you made up this data. I totally believe that you guys would do whatever it takes to lower down the cost, not for yourselves, but for the customers. However, I think you are testing the wrong HEPA filters, which are not created to be cleaned again. Many vendors have official guidance of how to maintain their Air Purifiers or Vacuum Cleaners:
    – Honeywell: 17000-S (https://www.honeywellpluggedin.com/air-purifiers/honeywell-true-hepa-allergen-remover) and 50250-S (https://www.honeywellstore.com/store/products/honeywell-50250-true-hepa-germ-fighting-allergen-reducer-air-purifier.htm) are used to be claimed “with Permanent HEPA”. Though later on they were changed to be “Long life HEPA”, their filters are still very effective for years after periodically vacuum cleaning (NOT washing with water). 50250 was even listed as Top 5 Best Air Purifiers by Consumer Reports as of May 2017 (the only one I could find for free on the Internet).
    – Sharp: one model I know that has instruction to clean HEPA filter by vacuum it, is FP-G50E-W (https://sharp.ph/product-list/fp-fg50e-w/).
    – HEPA washable vacuum cleaner: I have read some but right now could not find any. Sorry.

    As some of the team are in the US, hopefully you guys could repeat your test with any of the used HEPA filters listed above.

    Breathe safe!

    1. Hi Tu Ngyuen, Paddy here in Beijing, who performed these tests along with CK! I’ve also seen reports of ‘washable HEPAs’, and when we initially wanted to do this piece of research, our first idea was to go out and buy a ‘washable HEPA’ and test that (why, after all, would you want to wash a HEPA filter that’s not labelled as ‘washable’!?). After lots of searching, we couldn’t find any purifiers that actually said you could wash the HEPA filter. To us it seemed like these companies were claiming something that was too good to be true. Having said that, you’re right – if we really can get our hands on what a company claims is a ‘washable HEPA’ then we will definitely test it!

      1. Hi Paddy,

        Actually I am suggesting you guys testing on the ‘vacuum-able HEPA’, like the Honeywell 17000 or 50250. Unfortunately they are not sold outside US and Canada, so only guys who are living in US can conduct this test. Only one HEPA filter for Air Purifiers I’ve known about is washable, from Electrolux: http://homeappliance.manualsonline.com/manuals/mfg/electrolux/elap40.html?p=11.

        But for the Vacuum cleaners, yes, there are some, mostly known from Electrolux also. Here is one HEPA H12 washable filter EF H12W for Electrolux cycloneXL vacuum cleaner: http://homeappliance.manualsonline.com/manuals/mfg/electrolux/elap40.html?p=11

        I totally agree that HEPA filter efficiency will be decreased the longer we use it. However cleaning the right filter the right way should prolong its life cycle. Or maybe I am blindly believe in whatever the manufactures are telling us, who knows? I really wish that you guys could test it and reveal the myths.

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