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Comment by patrickk | Hacker News Reader

If you’re so inclined, you can build your own air purifier with laser cut panels or 3d printed panels and use a cheap ikea air filter and standard PC fans. All the parts are readily available, and user repairable.

If you pair if with an Apollo AIR-1 you can have home assistant ramp up and down the fans with a PC fan controller based on live readings of PM2.5 in your home. I did this with the help of Claude code.

https://www.thingiverse.com/thing:6826527

https://makerworld.com/en/models/2470181-nukit-tempest-euro-...

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if you're going to IKEA for the filters you might as well buy the whole purifier. it's cheap and it works well

aye, it's ikea and is cheap. this seems like a "i had a ton of parts around + a 3d printer" sorta thing

Looks like a cool project, but the 99.97% HEPA filters are the expensive part. Building yourself only makes sense if you want to choose your own aesthetics or enjoy doing it.

It also makes sense if you're worried that a proprietary filter will be yanked off the market, leaving you with an unusable item. Also, for the money, you cannot get that kind of smart functionality from my research.

My $50 (without the HEPA filter) air purifier can detect particles and change fan speed accordingly. It also has a light sensor to go into really quiet mode during the night.

Though, looking it up it seems that prices for the Winix Zero (including one set of filters) have doubled since I last bought one.

Didn’t the Apollo 13 crew make an air scrubber out of duct tape and hope? Surely a cardboard box, a box fan and a hepa filter covered in tape gets you 90% there

This was done during COVID and made international news.

You are referring to a Corsi–Rosenthal Box. You are correct that they will get you 90% of the way there, but they also tend to be large, loud, and ugly. We can build better things now that we have time and resources.

I really wish the DIY folks would measure the airflow and sound levels on this sort of thing. CADR and decibels are going to vary wildly with fan choice

I came across this site which has pretty comprehensive data about PQ curves (the chart for determining CADR given filter impedance) at different noise and power levels: https://www.cybenetics.com/evaluations/fans/204/ (many other fans tested as well but I've been liking the value of P14 Pro PST)

However they look somewhat commercial and I'm not sure the funding/incentives so definitely corroborate with other sources.

DIY folks are not a commercial outfit with access to testing equipment.

Having said that, there are reviews of some DIY models reviewing CADR[1], and it's bizarre to complain about testing decibles since Arctic P14 fans, the most commonly recommended fans, are a thouroughly tested product. Running them at around 25% based on lower PM2.5 readings is almost inaudible from experience.

[1] https://www.youtube.com/watch?v=ZjGJN57DgA8

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