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Comment by lispisok | Hacker News Reader

I see articles pop up like this all the time on HN like it's some kind of revelation. All you need to remove particulate matter from your air is a fan that pushes air through an HEPA filter. You dont need wifi, bluetooth, lcd screens, or a phone app. All those things plus some fancy instagram marketing is tricking people to spend $700+ on an air filter.

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>All those things plus some fancy instagram marketing is tricking people to spend $700+ on an air filter.

I think there is also the middle ground of spending about $150 on an air filter, because the ones from Ikea and Bluair look and sound much nicer in my home than a box fan with a HEPA filter duct-taped to the front.

I don't mind the repeated breathless excitement over it. It feels very on-brand for hackers to get excited about discovering a cheap and ugly DIY version of a commercial product and apparently miss that not everyone wants one in their kitchen.

That, and ignoring the other downsides of a hacked together device - noise and power consumption.

The Winix 5500/5300 are pretty great. Super quiet and use 5-8 watts at setting 3 of 4. Box fans can't really compete there.

Yep - I got a Winix 5300 ~3 years ago and it's been great. Nice and quiet, low power, and the squirrel cage blower in it is really good (which is rather important - you need a lot of static pressure to push/pull air through a HEPA filter and box fans just aren't really up for the task at low levels).

Despite appearing almost identical, I haven't had good luck with the Winix C535. All 3 had poorly balanced blowers that either ticked or rattled, which wasn't the case in the 5 5500/5300 I've owned. It's a pity because they're super cheap at Costco.

It's not trivial though - it's not easy to 'push air through a HEPA filter' - you need to shop for a motor, blades, and filter more than simply fan (comprising motor and blades) and filter really. Or at least you need to be aware and get a suitably beefy fan - I think $50 is a hard budget to hit just for that reason. Or at least it is if you don't have easy access to cheap 'box fans' that are for some reason so prevalent in North America (what's their usual use?).

You can spend a lot of money on just a fan, it's not just air purifier marketing nonsense.

Unsure about the entire US... For my area they were called "window fans" in previous times. Before air conditioning was prevalent, you'd use these box fans, placed in the window, to circulate air to provide a more comfortable environment.

In years past, the fans were beefier than the current generation. They also used metal fins. Speaking into one made a vaguely similar effect to speaking Like Darth Vader. It was entertaining as a child.

Agree! However article is comparing to a $100 option and he spent about $60 on DIY supplies. The price differential is small enough that nobody should DIY. The convenience of having an auto-sensing device that turns on and off when based on changes to air quality is well worth the extra. As is the ultra low noise operation and added aesthetics.

> nobody should DIY

> nobody should DIY for price reasons

FTFY. Lots of reasons to DIY other than price :)

He's comparing a $100 option that does not have an auto-sensing device to a $54 option (that also doesn't have a device.)

This is pointed out by the author:

> Some (more expensive) commercial purifiers have air quality sensors built in and automatically turn on only when needed.

So in this case, you still have to manage fan speed yourself. Overall the bigger picture would include cost of filters over time, as well as electricity (which may be in favor of the commercial unit.)

And finally, you have to consider the dollar value of aesthetics!

IDK if that's true, I have one that I paid about $100 for and has sensing. It's quite nice and I basically never know when it's on it's so quiet. It also came with a reusable/washable filter, so I've never had to replace it after about 3 years of use now. Any ways, I DIY a lot of stuff, but there's not enough interest in this one unless you're just a glutton for frugality or find some interest in this particular project. My point was that for most people this would be a negative time value of money for inferior outcome; which I think are why most people DIY things... so they can afford better or learn something. (There is no learning when all you're doing is strapping a filter to a box fan.)

The DIY option should have been closer to $30 if they used a 20x20x1 filter (~$10), which fits perfectly on a box fan.

Also, I have yet to find an $100 air purifier that has a high enough CADR to filter a large living room.

I built a big DIY one and then immediately bought a non-DIY one for my bedroom.

The filters are going to cost a lot more, but it looks a lot nicer and I don't have to think about turning in on and off - it's runs on auto.

You don't even need a HEPA filter. A lower grade filter will do fine as well for recirculating air: the idea is to reduce particles by passing the air of the room again and again through the filter. If you have a air source that has more particulate pollution than the sink a better filter makes more sense.

None of these articles allude that you need any fancy tech to filter air. You're preaching to the choir.

The people buying $700 air filters are typically not very tech or DIY inclined, although HN does tend to fall for "expensive is good" kind of marketing once in a while (most notably - Apple)

Expensive _is_ good […] once in a while. Most notably, Apple.

Can you show me a Windows laptop that has Microsoft telemetry disabled permanently?

I dont think anyone is confused about this.

Do you want to see/measure/track air quality? Do you want to be able to remotely control the purifier? Do you want a device that looks good? Do you want other features like heating/rotation/etc. Those are the reasons you might buy one...

Yeah, but if it doesn't have all that fancy stuff then the geniuses here couldn't lock you in to Air-As-A-Service!

These articles have been popping up ever since the cheap air quality sensors started showing up that everyone and their dog hooks up to their raspberry pi like it's some grand revelation. I wonder if the measurements also have a logarithmic quality making the change in absolute values after turning on a filter appear more impressive.

Skip the HEPA and use a MERV 13-16 filter. You’ll get better results at lower cost.

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