I Made a Quieter Air Purifier

Summary

DIY air purifiers could help reduce disease transmission at lower cost. But, they are loud. And so people turn them off. I’m not aware of a formal study that has measured the noise of an air purifier against its usage, but there’s probably a relationship - based on observing how people in my house interact with the CR box. If this is true, and if we are trying to maximise total air cleaning, we don’t actually care about how effective air purifiers are in isolation. Rather, we care about how quiet they are too. We’d rather have a weaker air purifier that people leave on for ten hours, rather than a noisy one that they only turn on for an hour. But to maximise this tradeoff, we need the data on: We would then choose the air purifier that has highest usage times effectiveness. But again, we don’t have noise versus usage data. In any case, there is no point in a strong air purifier in a classroom of kids if it gets turned off by the teacher. We need to get the air purifiers quiet, so that people use them more. This is my attempt to do that. The standard DIY Corsi-Rosenthal box uses a Lasko box fan. As of now, it’s pretty loud, even on its lowest setting. I made this previously and analysed it here. I am trying to get this DIY CR box quieter. So, I built a prototype with PC cooling fans instead. PC cooling fans are an industry where quietness is actually something they try to optimise. This is the prototype: To do this, I bought some Recticel insulation foam and bought 5 arctic pc fans. I cut the Recticel foam in to a square to match the size of my four MERV 13 filters. Then I cut out 5 square shaped holes with a box cutter and then taped the pc fans inside. I hoped that the foam would be good at damping sound as well. I then stuck the lid on top of my filters.To power the PC fans, I attached them to a fan hub which was powered by SATA power. And then I connected this to an adaptor that takes mains as input, and outputs SATA. Not badly! I used the same 20 match test that...