3M公司最近在售卖可以安装在空调入口的空调滤网。它们的营销口号是「3步轻松安装，空调+滤网秒变“空净”，有效减少室内PM2.5」。3M空调滤网清洁空气的效果如何？真的有效吗？我们将在本文中找到答案。
3M空调滤网的工作原理
过滤空气中的污染是非常简单的。你只需要一个风扇和一个滤网，你甚至可以自己动手DIY一台属于自己的净化器。
空调是一台吹出冷空气的风扇。所以3M空调滤网背后的思路是，通过把滤网贴在空调的入口，空调将吹出洁净的冷空气。
3M空调滤网清洁室内空气的效果
3M公司声称，他们销售的滤网可以捕获小至0.02微米的颗粒，在一小时内可以去除83%的PM2.5。但是他们没有提供任何关于测试的信息：房间有多大？空调设定的速度是多少？为了回答这些问题，我们对3M滤网进行了一系列测试。
在一个20平方米的房间里，我们在空调上安装3M滤网后，测试了空调开启前后的PM2.5值。
结果显示，在装有3M滤网的空调打开后，PM2.5浓度大幅下降。空调运行1小时后，PM2.5从33 μm/m³下降到4 μm/m³，降幅达87.9%。
当空调关闭5小时后，室内PM2.5浓度再次开始上升。说明3M滤网+空调组合确实有助于保持室内PM2.5处于较低的浓度。
安装3M滤网后，空调功能还能正常使用吗?
在空调上安装3M滤网会增加空气阻力，意味着空调需要更加努力的工作。在测试中我们发现，安装3M滤网后，空调出风口排出空气量减少了22%。
尽管如此，空调仍然能够将20平方米的房间冷却到20摄氏度。值得注意的是，空气阻力的增加可能会导致空调电机的磨损，降低其使用寿命。如果您计划在您的空调上安装3M滤网，请确保不要覆盖整个空调排风区域。在边缘留出间隙虽然会降低过滤效率，但有助于降低空调电机的工作负荷。
Smart Air的测试表明，3M空调滤网可以有效降低室内PM2.5浓度。在我们20平米的房间里，空调开强风1小时后，PM2.5浓度降低了87.9%。空调滤网会降低风量，但空调仍然能够维持20摄氏度的室温。还不错哟～
where can you buy them?
“It’s worth noting, however, that the increase in air resistance may cause wear and tear on the AC’s motor, reducing its lifespan.” doesn’t make sense! The centrifugal fan will do a bit LESS work with the reduced airflow, and draw less current.
The lowered airflow will have the same effect as a lower fan speed – less air through the evaporator coil. I suppose if a low fan speed along with a clogged filter may freeze up the evaporator.
I never found a peer review paper showing that 3M Filterete filters have been shown having a sustained efficiency in removing particulates. This triggers an alarm that well controlled experiments may have never
demonstrated efficiency.
I did a similar experiment to assess the efficiency of 3M filter attached to an air conditioner. It did decrease by a half the PM2.5 concentration measured by two independent devices for a few hours. This apparent effect was not sustained after 8 hours.
Adding filters to you AC is not a great idea – like others mentioned you degrade the performance. The fan in your AC is designed to have HUGE airflow but only at really small pressure. If you add ANYTHING to its path, you will decrease the airflow quite a lot. This will not only reduce the performance but also degrade efficiency as the coolant leaving the indoor unit for the compressor is still pretty cool as it didn’t have enough airflow to heat up more.
With these filters fitted the airflow is reduced, therefore the system temperatures/pressures are affected, which will reduce the efficiency and running costs