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Dyson air purifier outperformed by cheap DIY box fan filter in Marketplace test

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Re: Dyson air purifier outperformed by cheap DIY box fan filter in Marketplace test

#361

Post by danans »

Dylan16807 wrote: post #322
danans wrote: post #312

Earlier quoted context omitted.

You're right about the orientation. I've fixed the diagram. But they don't just use 1 filter, they use a series of them, like you can see at this timestamp of this video: https://youtu.be/8f6Ih09uaDw?t=401

Oh, I see. That's a weird hack to get more surface areas instead of just using a deeper filter. All the pictures I could find were systems like this that do just use deeper pleats: https://images.allergybuyersclub.com/img/IQ-AP-HP-airflow.jp...

I could be wrong, but I think using separate filters distributes the air streams across independent filtration channels, reducing the static pressure of the system. Similar to a pleated filter, the angular orientation is probably about packing more surface area into a smaller space vs. parallel filter channels oriented linearly.

Re: Dyson air purifier outperformed by cheap DIY box fan filter in Marketplace test

#362

Post by mindcrime »

Dylan16807 wrote: post #282
mindcrime wrote: post #146

Earlier quoted context omitted.

From the HN guidelines: Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith.

I'm not sure what you're implying, because both interpretations are valid to downvote.

I'm saying that this statement especially when your "question" is an argument hidden behind a question mark, is not consistent with the suggestion to "assume good faith" espoused in the guidelines.

Re: Dyson air purifier outperformed by cheap DIY box fan filter in Marketplace test

#363

Post by nostrademons »

ljf wrote: post #34
tidepod12 wrote: post #16

Earlier quoted context omitted.

Yea, it's weird reading this thread to me. I have a cordless Dyson vacuum and it is by far the best home vacuum I have ever used, both in terms of suction power (even compared to non-cordless ones) and in terms of other usability/features.

We must have had a dud as we got the Dyson animal hair one and it was terrible. Battery life was rubbish, the suction was crappy and the pick up just wasn't that good. Ended up getting a gtech which was fine for 2 adults in a small 2 bed house with wooden floors, but now we have kids and a bigger place we got a Shark corded and it is amazing. Literally the best vacuum we've ever owned.

We have both a Dyson cordless vac and a Shark corded one. We use them for different things - the Dyson is for spot-cleaning, toddler messes, cars, furniture, bedspreads while the Shark is for our floors. Both are very good at what they do.

Re: Dyson air purifier outperformed by cheap DIY box fan filter in Marketplace test

#364

Post by krrrh »

gonehome wrote: post #206
ortusdux wrote: post #4

I still cannot get over this product. They whole selling point of a dyson fan is the 'air multiplier' tech, which creates a low pressure zone that propels air through the ring. According to dyson, this tech can move 15x more air than the fan in the base of the unit. Why in the world would you build an air filter around a system that does not directly interact with 93% of the air it moves? https://www.jameco.com/Jamec…

The fan also sucks compared to something like a Vornado. "Buffeting" of air is not a practical issue when using a fan - you want a fan that can create a lot of air flow. The Dyson fan comes across form first then making up reasons to explain the form retroactively. It feels like an interesting look is the goal rather than something that's actually better. Am I wrong about this? Do people that have the fan like it? Is…

I have one that we keep in our daughters nursery. The thing I like most is that it can run in auto mode and night mode meaning that it’s on all the time and the fan only runs from level 1-4 out of 10, which also means silent operation. It has a sensor for air particle and VOC that causes it to turn up. It seems to work (like if I fluff pillows or make the bed beside it it will detect a spike in particulates on the graph around that time. So, set and forget, silent operation, and safety for small fingers made it the best choice for us despite tests showing lower efficacy over a defined time frame.

Re: Dyson air purifier outperformed by cheap DIY box fan filter in Marketplace test

#365

Post by sdljfjafsd »

nostrademons wrote: post #359

My wife rigged up a similar box fan + HEPA filter + duct tape solution during last summer's CA wildfires. They are remarkably effective. We also have the BlueAir purifier that was top-rated in this report, and arguably the box fan did better. (The BlueAir is better for kitchen smells, the box fan is better for particulates like wildfire smoke.) I think the filters are like $40 each from Costco and the box fan was $30…

Why did you believe the box fan did better? Did you do any kind of testing to verify that? The Blue Air's CADR is 2.7x that of a box fan.

I do agree that the box fan solution is a great low cost option for small to medium rooms, but if you need 1 device to purify a large area, it's not gonna cut it.

Re: Dyson air purifier outperformed by cheap DIY box fan filter in Marketplace test

#366

Post by catmanjan »

Judgmentality wrote: post #344
VRay wrote: post #339

Earlier quoted context omitted.

Yeah, if the kid grows up he'll be awesome for sure

Would you rather take a chance at greatness, or a certainty at mediocrity? No guts no glory.

Surely laughing when your child falls over leads to them enjoying others misfortunes

Re: Dyson air purifier outperformed by cheap DIY box fan filter in Marketplace test

#367

Post by hedora »

I wish they'd tested this DIY air filter instead. They made a 20" cube, where one face is a box fan, and four faces are filters. Brilliant:

https://www.thisoldhouse.com/green-home/22231148/diy-air-fil...

It should have a much higher CADR than the single filter version at lower backpressure. That means less noise and more energy efficiency.

Re: Dyson air purifier outperformed by cheap DIY box fan filter in Marketplace test

#368

Post by nostrademons »

sdljfjafsd wrote: post #365
nostrademons wrote: post #359

My wife rigged up a similar box fan + HEPA filter + duct tape solution during last summer's CA wildfires. They are remarkably effective. We also have the BlueAir purifier that was top-rated in this report, and arguably the box fan did better. (The BlueAir is better for kitchen smells, the box fan is better for particulates like wildfire smoke.) I think the filters are like $40 each from Costco and the box fan was $30…

Why did you believe the box fan did better? Did you do any kind of testing to verify that? The Blue Air's CADR is 2.7x that of a box fan. I do agree that the box fan solution is a great low cost option for small to medium rooms, but if you need 1 device to purify a large area, it's not gonna cut it.

No objective data, because what I care about is usually "Am I choking on smoke? Will I stop choking if I run the air filter?" Subjectively we were still having problems with just the BlueAir (~1000 sq ft apartment), add the box fan and things got better, take away the BlueAir and things are still better.

The filter on the box fan also got black faster, which is our indication that it pulled more particles out of the air. Makes a lot of sense, because the actual filter material is the same (they both use HEPA filters inside) but the box fan blows a greater volume of air through a larger filter area.

Re: Dyson air purifier outperformed by cheap DIY box fan filter in Marketplace test

#369

Post by sdljfjafsd »

chmod600 wrote: post #354

> "I think what we're trying to do is pull back a little bit from the CADR metric," he said. "Not everyone needs an enormous CADR, has huge rooms or incredibly dirty air." It seems plausible that CADR is becoming just a bigger number without improving effectiveness, like megapixels. It also seems plausible that Dyson is just struggling to avoid commoditization because it's a losing battle for them. And it's possible…

CADR is an important metric for determining if a purifier is correct for your room. You can use it to calculate how many air changes it does per hour. If that number is too low, the air purifier is not going to work well in your room. Basically there's a minimum CADR for each room in your house, but of course, exceeding that gives you little benefit. Most people search for devices that are ~4 air changes per hour.

Re: Dyson air purifier outperformed by cheap DIY box fan filter in Marketplace test

#370

Post by hedora »

krrrh wrote: post #364
gonehome wrote: post #206

Earlier quoted context omitted.

The fan also sucks compared to something like a Vornado. "Buffeting" of air is not a practical issue when using a fan - you want a fan that can create a lot of air flow. The Dyson fan comes across form first then making up reasons to explain the form retroactively. It feels like an interesting look is the goal rather than something that's actually better. Am I wrong about this? Do people that have the fan like it? Is…

I have one that we keep in our daughters nursery. The thing I like most is that it can run in auto mode and night mode meaning that it’s on all the time and the fan only runs from level 1-4 out of 10, which also means silent operation. It has a sensor for air particle and VOC that causes it to turn up. It seems to work (like if I fluff pillows or make the bed beside it it will detect a spike in particulates on the gr…

We recently bought the giant one with the ridiculously high CADR. They removed the air quality sensor (covid parts shortage?), so there's no auto mode for that model, at least. :-(

It's noisier than expected, but on low it's quiet enough and fine for our entire house during "normal" bad pollution days (PM 2.5 between 100 and 300). During severe smoke from wildfires (PM 2.5 > 300), I'm OK with it being noisy.

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