embarassing
Regardless technology is often named after people who made it popular, especially when original inventors are unknown or too diffuse.
i build one like this back in 2018 during california fires. used it mostly in garage for filtering air when i work on "things". decommissioned it last week.
i guess i am not the only one who came up with this idea prior to covid as this is pretty obvious
other refinements were using a shroud to prevent back flow
you don't need a lab to figure out that replacing 1" filter with 4" filter and even better arranging multiple filters in a box will improve flow rates and filtration (especially for box fans that not really designed for static pressure)
corsi&rosental work, imho, is equivalent to lab work reporting that you can move more water through 10" pipe than through 1" pipe.
hence extra research by Corsi and Rosenthal is needed. After they will do the measurements they can be declared as inventors of p100 masks, that will be known as Rosenthal-Corsi masks
If you create some novel car design that gets discussed enough, maybe it will get popularized and get named after you. ie Bangle butt, for the E65 BMW 7 series.
i refused to sign my name on a bunch of patents at work because they were too obvious (they were still granted USPTO)
https://scosman.net/blog/using_in_wall_computer_fans_for_hom...
There's also systems which can move air both ways through the whole house - https://www.ventilation-alnor.co.uk/index/support/alnor-know...
Your DIY solution looks a lot cheaper though.
https://www.amazon.com/dp/B01728NLRG
Quiet, efficient, works super well
but 5x arctic cooling PC fans is ~$100. the commercial versions are easily available, more effective, no more expensive, and don't look like a box of furnace filters taped together.
But I'd honestly pay a premium for a commercial air purifier that just has a bunch of 120mm/140mm fan mounts instead of their "maybe tolerable at Very Low" integrated box-fan equivalent.
In general, all I've learned from online reviews of "quiet" appliances is that different people have very different definitions / criteria for "quiet".
i also have iqair which according to reviews is quiet at low speed. in my experience this quiet sounds like airplane (i got it replaced once. apparently it's just the way it is).
Sure, you can't hear it from 10ft away - but how much air is it moving at that setting?
I have various configurations of these PC fan setups and the Arctic P14 Pro that you can get 5 for $32 on amazon are honestly wildly effective and designed for applications with some static pressure (radiators and such).
So we're back to; effective or quiet, you're only going to get both with the PC fans, for now.
Rabbit Air (i think they closely related to conway) you can hang on the wall as art piece.
Recently a daughter moved into a really nice apartment close to a major university/freeway where she will live for the number of years it takes to get a Phd. I got concerned about tire dust. So I am about to start building a really nice air DIY air filter using eight Noctua NF-P14s (about 1000 cfm). XMas present.
I really wanted to use merv-13, but got quite worried about air flow restrictions, plus cost to replace (assume monthly). Instead I went with two 12x24 Carter reusable electrostatic merv-8 filters. I use Carter filters on my house blower, and really like them (just washed them... scary how much junk is in household air). Also, I got the 12x24 direct from Carter for a very low price as they were returns. Note: This is NOT a low cost project, but I just got scared re: merv-13 so went with what I know.
Anyway, the final product will NOT be like this guy's DIY. I will use my somewhat decent woodworking skills to fashion a good looking standing "lamp like" appliance that should look good in most living rooms. I am thinking of going with knotless cedar as I really like working with cedar, and there are some mills here in NW WA where one can go to get such wood (not a HomeDepot specialty).
My question is whether an electrostatic merv-8 filter would do well with tire dust. I am not looking to create "clean room" conditions in the apartment. Just get rid of some of the bad stuff. I am very weak re: understanding filters, mervs, etc. APPRECIATE any insights. Thx, RF
vid of the noise levels https://youtu.be/wOc0TM1ErYA?t=195
The lead line for this article pretty much reflects the reason for my post: "The air purifier marketplace is an apt metaphor for how a particle must feel while being trapped in a filter - at every turn there's a new acronym or regulatory agency or purifier type."
In any case, if you see lots of gunk, that’s not the hard-to-filter stuff. I can say, as the proud owner of a monstrous HEPA filter with a dirt cheap noting-special MERV 8 pre filter and an utterly boring metal louver before that, all continuously collecting outsize air, the louver gets a bit gunky, the MERV 8 filter turns black after a while, and the HEPA filter is indistinguishable from brand new. This whole system replaced an older “ISO ePM1” (yes, the manufacturer conveniently forgot the number after that, but it’s MUCH higher spec than MERV 8), and the indoor air quality as measured by a little particle sensor suggested that the ePM1 filter missed about 50% of the outdoor PM2.5, whereas the new system produces air that measures zero across all particle sizes. And that ePM1 filter did a fine job of turning black :)
Get a particle counter and test your system!
P.S. the HEPA system uses less power and will cost less to operate over time because it is HUGE but has the same flow rate.
At some point I found a nice chart, IIRC from the EPA, showing the efficiency plotted vs particle sizes for a variety of filters. IIRC the filters generally split into two categories: those with decent efficiency all the way down to zero microns and those with very poor efficiency at small sizes. IIRC the split was around MERV 12. Obviously your filter is not the filter in the chart.
So I would go with MERV 13 or even a bit higher. Also, keep in mind that pressure drop is related to the velocity of air through the filter, so a physically larger filter will have lower pressure drop at the same flow rate. But the need to replace a filter is related to collected gunk per unit area, so doubling your filter area will cost twice as much but last twice as long and will use less power and run quieter.
Also, electrostatic filters can lose their charge from exposure to various contaminants.
edit: it was the chart here, also mentioned down thread.
https://www.frdmtoplay.com/nagivating-air-purification/
Portable Air Cleaners, Furnace, and HVAC Filters. 3ed. EPA 402-F-09-002
And I remembered a bit wrong. Even MERV 10 will pick up the smallest particles, but MERV 8 may miss some. But for good performance at the most penetrating size, you want MERV 12-ish. For a single-pass filter (filtering outdoor air as it enters), you want much higher - MERV 16 or even HEPA or near-HEPA, if you want acceptable performance against potentially nasty outdoor conditions due to wildfire or nasty human particle sources.
I would stick with merv-13 because you'll get solid performance across a lot of things you might want to remove, from viruses to general pm2.5 and things like volatilized cooking oil. Clean air is awesome and tire dust isn't the only thing that's annoying.
Re: Filter costs - stock up when costco has them on sale, which seems like every few months. They've got Filtrete 2500 (merv 14) for 3 filters for ~$35 if I remember correctly. I use them in my CR boxes and those I built for family (which I give them with a 3 pack of new filters and also instruct them to refill during costco sales)
I built one for a local stray cat rescue where it literally sits in the middle of the living space for 10+ cats, it's 4 months now since they started using it and the filters look quite dirty but the air flow is surprisingly still very good. (4x Noctua NF-F12 iPPC 3000 fans and 4x 16"x25"x1" Filtrete 2500 filters)
Here's some info re: which merv levels work best with various fan combinations (looks like if you're going to go with higher merv you'll need the static pressure to be able to continue to pull through them with any reasonable airflow once they're getting loaded up with stuff) - https://www.cleanairkits.com/blogs/news/what-happens-to-cadr...
Remember that as the filter starts to get dirty, its filtration effectiveness actually increases, though the airflow rate drops. CADR will drop but less than just watching airflow would predict.
1. Are box fans just really terrible? I would expect the amount of airflow from a box fan to absolutely demolish these little case fans.
2. Does airflow not actually matter that much? Assuming the box fan really does move far more air, that would imply that air filtration is somehow not driven by air flow. Or else the testing methodology is flawed.
Computer cooling fans also might not have been designed to handle that much "load", but in the case of the box fan, we have an actual report of someone who almost burned down the house:
I had a dishwasher catch fire because the installers didn't properly connect the power cable. That doesn't mean dishwashers are inherently a fire hazard.
The PC case fans have been specifically designed to be as quiet as possible. The Lasko box fan ... well, these are cheap fans. They're designed to be manufactured at the lowest price possible while still meeting the low quality bar of "It's acceptable considering I got the cheapest option that WalMart carries". But in general yes, box fans are terrible.
AFAIK PC fans are designed to move air at low pressure while quality air purifiers are designed to handle more pressure.
Other than that, it’s a neat writeup. Would like to see a follow-up with static pressure considerations.
I have a similar setup, just premade from CleanAirKits.
Allergies are gone, house has far less dust and cat hair floating around.
Can't do anything for wood smoke though, that would need carbon filters - which run out quite quickly.
1. A furniture company that decides to integrate a purification system into their offerings can hit it big. Imagine a big, heavy dresser in your bedroom that sucks in air from the bottom and pushes up to the top or a TV stand that where different compartments are filter media. The mass of these reduces noise and vibration and allow for larger, slower spinning blowers and larger surface area of filter media (less static pressure, longer replacement intervals, easily hold pounds of activated charcoal).
2. One needs to pump in oxygen from the outside and exchange the indoor air with the outside air. Circulating and cleaning the air in the home, especially with modern doors and windows, will become unpleasant in a short while, especially during wildfire season. The positive pressure this creates also helps pollutants stay out, if done correctly.
I would absolutely go the diy route using large filters, activated carbon, housed in a wooden box with a blower and implement something like AC Infinity's in-line filtration systems to pull outside air in through a window, with a large carbon filter on one end. Or if a homeowner, set up a more permanent solution. https://acinfinity.com/inline-fan-systems/
runariot•2mo ago
brtv•2mo ago
pixl97•2mo ago
chr-s•2mo ago
https://old.reddit.com/r/crboxes/ is a good resource if you're looking to make your own. There's been a general shift from large box fans to PC fans because their performance/noise ratio is better.
nbf_1995•2mo ago
With the fans blowing in, all the dust is on the inside of the box (and on the fans).
The box fan version also blows air into the box