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Thanks for the video! The advantage to placing the filter on the back, is that the filter stops the usual build-up of dust and dirt on the fan blades (which .. over time, puts more drag on the blades which may heat the motor up a little with extra work and less airflow). Meanwhile, putting the filter on the front stops the dust/debris escaping, which slows the exit airflow a little and (admittedly, slightly) encourages the build up of dust on the blades and doesn't protect the motor. So for single filter setups, I'd recommend the back mounted filter, and you get the aesthetic benefits that are mentioned in the video and unobstructed access to any front-panel controls. As found in the video experiment... the amount of filtration should be (for all intents and purposes) identical if the fan speed and filters are the same. However, if the experiment ran for months until the filters were clogged and needed replacing... that story might be a little bit different. Taking it further.. two filters of differing types: A lot of wood workers, noticing the sawdust buildup accumulating in their workshops are putting filters on both the front and back of fans (Google/RUclips search: "DIY workshop air filter", and you'll get the idea). These usually involve two or more filters, with the typical air filter for the larger dust/particles/fibres on the back and another, 5 micron HEPA filter (or something similar) on the front. Naturally, this filters the air to a much higher quality, but also increases the cost of construction and ongoing maintenance. While you want a nice sealed "bottle neck" around the fan itself for efficient airflow, it's also better if you have a slightly larger filter than the fan on both sides as this reduces the "back pressure" the filters will place on the motor. If safety is your biggest concern, the best things you can do: 1. Keep your house as clean as possible... the less dust your filters are exposed to, the longer they'll last, and airflow will be less restricted. Put simply, there's less to catch on fire if there's a problem, and it's a situation that's less likely to cause a fire too. :-) 2. Clean and replace the filters regularly, (or as needed in times of low air quality). Clean any build up on the fan blades and suck any dust out of the motor with a vacuum. 3. Electrical safety. If you're enclosing a fan inside a box, then having a dedicated "safety switch" which (depending on the type) is usually either a Ground Fault Circuit Interrupter (GFCI) or Residual Current Device (RCD). These devices create an automatic way to cut the power to the fan in the event of a fault. Differing laws and electrical systems are found in differing countries, but research how things are done in your relevant area or talk to your local qualified electrician and they'll give you appropriate advice. However, we can buy RCDs in Australia for around $20-30 in our nearest hardware store. Installation is easy. Plug the RCD into the wall, and then plug the fan into the RCD. Turn on the fan and make sure the switch trips the power by pushing the "Test" button, then hit the "Reset" button to turn the power back on. I hope this helps someone out there in these crazy times!
Ya makes way more sense on the back nearly every fan ive had that failed was due to dust collecting on the motor and building up till it has to much resistance and fails. Also i never run it on max speed and the motor stays cool enough within spec.
@@rickfrank7934 I left him a comment - but didn't hear anything - nor do I expect to. Maybe we'll see a video sometime. Head over and leave Todd a message too! Maybe if we get enough folks suggesting it he might indulge.
Best reason to put FILTER ON BACK is because you're filtering the air BEFORE the dust gets to the fan motor. If this was near a dust source that can build up (like saw dust) then the dust can not collect on the back of the motor because the filter collected the dust first. This reason alone is important enough to make it the preferred method.
Great video! I saw this idea, (same as yours), some months ago. The idea bounced around my head for a while and I decided to build one. One $18.00 Walmart fan and a 20"X 20" filter, the most expensive one Lowe's sells, taped it on securely and it has been running constantly for 6 months or so. The fan motor hasn't gone south but I change the filter every 2-2.5 months. That worked so well, I got another fan and filter and some duck tape. That one has been running for nearly 3 months. We have a HEPA filter in the bedroom due to my wife's allergies and my COPD. The fan filters do make a difference but I have no way of testing its efficiency.
*Works great with **Fastly.Cool** , exactly as described. Love the fact that it can push, pull, or exchange air with the push of a button. The remote is a nice bonus too!*
I’ve used this method while replacing my attic insulation in mid summer. Not only did it filter out the insulation particles it still dropped the attic temperature by 10 degrees. This works and I’m planning to use it to take some of the strain off of our home furnace. 👍👍
Great tip. I have a box fan with a filter on the back 7 micron filter in my woodshop . I turn it on at the end of the day to help clean the air of wood dust. I have it on a timer. It runs for 3 hours.
Great video! While the Corsi Rosenthal box seems better when it comes to performance, this single-filter version is MUCH more portable. I'm pleased to see that the fan motor didn't heat up that much. If you're really that concerned about this issue (or if you want to reduce the electricity usage or make the filter last longer), you can connect the filtered fan to an electrical timer and set it to automatically turn on and off every half hour.
I have been using this setup in my metalworking shop since 1989. Never had a problem. I just use a box fan, a filter, and a couple of bungee cords. The Walmart box fan has to be replaced about every decade. I always get the cheapest one. I wish I could find one of those old all metal box fans from the pre ‘80’s. Those things ran forever.
I like your bungee cord idea. I don't feel like getting too fancy but I also don't want to deal with tape. This is the perfect solution and easy too! Glad I read your comment! :)
I agree with you, they last a long time and can run for years with a filter. My little dog liked to sleep in from of my box fan air filter. It was kept on 24 hours a day for over 3 years. The fan still works fine. I made a video of my little wooden clamp with a magnet and handle I made to attach the filter. "DIY $6 Magnetic Dust Fan Filter air cleaner for Home & Shop"
Great testing! Good to know what the temps are! If people are worried about static pressure and strain on the motor they could get larger filters. I think you can get 20"x20"x2" which would double the filter surface area so more air will pass through. The larger the filter media the longer it lasts before clogging to so that is an advantage. I have that exact fan and been using it in a custom wooden box for 3 years. I made mine for a 20"x25"x5" filter which is 5x the surface area of a 20"x20"x1". I can run the fan on medium and get more airflow in the room compared to the smaller filter on high with all that extra surface area passing air. If you really want the motor to last long and quiet the fan down a little, I put a link to a video on balancing the box fan blade below. The bearings will have less stress on them and it will be less shaky when running but I use mine on medium speed so I'm already putting much less strain on mine so I never tried to balance the blades. ruclips.net/video/moo95i_6QZs/видео.html
I just build a cube using four filters, the fan, and cardboard for the base. 13 merv 20x20 x2. Wow! Amazing filtration. Seems to be helping my COPD person.
@@pattip1413 That is a lot of filter surface area going with the 2" filters! Just slightly more than my 20"x25"x5". Sounds like its doing a great job for you and you'll need to change the filters less with that much filter dividing the air going through the box!
THANK YOU for the deep dive on this! I just ordered a $160 air filter, and am having 2nd thoughts. I did this a few years ago, and I noticed one thing: When you put the filter on the front, fan blowing at it, a whole bunch of air bounces right back at you from the rear!
Definitely better to put the filter on the back, and you can seal the edges with painters tape and place a shroud on the front to decrease backflow - check out the diagrams here: en.wikipedia.org/wiki/Corsi%E2%80%93Rosenthal_Box
Perty neat video Sir. You obviously put alot of time & effort into this project. Even the amount of time you spent on just the editing is outstanding. Good job!
1 advantage to having the filter on the inlet (back) side is the same reason furnaces are built that way: it keeps the motor windings cleaner which reduces fire/smolder hazards from dust build-up.
Great Video ! if u Want to Add a Measure of Safety and don't want a Paper filter Slammed up tight against a hot motor. Space it away from the Rear of the Fan unit by a Few inches using Sheet metal and a Hvac Filter Rack.
Thanks for the experiment. I have put a wifi switch with cloud timer in it. It is a little bit fancier. So, every two hours and stop for an hour (whatever you like for cool down the fan) around $10 to $15. But when your son's nasal allergy get improve much better, that makes me starts to make one for every room.
Cloud just mean that the app store your timer setting in a server somewhere we don't know. Actually not quite knowing that my wifi switch timer info on the cloud or in the app or in the switch itself.
Run it for 4 months now, and I put have put a UV light and hide behind the filter against the wall for extra sanitizing and no direct UV light exposure to me. But that is really good for cleaning the mold (even covid) in the air.
I remember in our high school wood working/ construction class my teacher had several of these spread around his classroom to help keep the wood dust down. It actually helped tremendously. He did have a homemade dust collector system he rigged up with pvc pipe and an old car wash vacuum cleaner he put outside he had attached to the various saws that would automatically kick on whenever the equipment was turned on. Our school district was too cheap for a true dust collector system and air filtration. Luckily the new clean air regulations in my state got him a much needed remodel for his classroom. He said that in 1996 the high school finally got modern hvac systems in the classrooms so most of the teachers were throwing their old box fans out he said that he , the metals teacher and the automotive teacher collected them and attached brackets to them to make filtered air machines for their classrooms. I always admired him for collecting things other people were throwing out. His philosophy was to reuse, renew, and recycle as much stuff as possible.
Great video. I am looking for a CHARCOAL air filter because my main concern is VOCs (super small particles like fire retardants in rugs. formaldehyde in mattresses. inorganic clothing ink dyes off gassing etc) Will these filters work? Or is the a 2in1 hepa / charcoal filter? thanks
Nice experiment. I have been using this system to remove dust from my garage work area when I have been doing wood work. I only run the fan with the filter for maybe several hours during and after I generate dust. I have always put the filter on the back (intake side) and it certainly clears the dust from the air. Also tried it in the house during pollen season and it also seems to work. The problem is that the fan makes noise and my wife doesn’t like it. Been using Honeywell or 3M brands both rated for dust and dander I get at Home Depot. No MERV rating provided on the packaging.
I just bought a Lasko brand fan with a filter that goes in the back. I'm not as crafty as you, so it was $60 well spent. Thank you so much for the idea! Love your videos.
I truly want to thank you My husband wh is 81 early emphysema asthma and we have cats we wee facing the hard reality that we might have to get rid of the cats I was exploring HEPA filters and found your video. I was thinking of making my own and you showed me that I'm not crazy. Again Thank you!
this is a good enough test. You covered enough bases to prove your point. Been using box fan filters for over a year now. MERV 5 and now MERV 8 filters. I own a cat and a couple of my grandkids have cat allergies- the box fan filtering makes a HUGE difference... according to them. Project Farm would be proud :)
I bought about a $50 Lasko fan where you clip a 1 inch thick filter on the back, so I suppose since a fan company does it that way they must have tested it in their development phases. Thanks for a great video!
We use this setup in my sons’ room and it is good. In my room I use a Winnix air purifier with a HEPA filter and for allergies that works best but both are impressive and helpful. I feel better after seeing your video.
Very nicely done review. Simple, straight-forward and informative. I think you put a nice balance between "scientific" results and real-world application. Important also, which many other experimenters tend to neglect, was the ambient temperature. ....you measured it (thanks). . Thanks for your efforts, thanks for sharing.
Excellent video - Because of the Chinese Wuflu 1 year ago I made 3 box fan filters except I used 4 inch thick filters & I used MERV 13's that filter viruses from the air.. The 4 inch are quite abit more $$$ but they last longer and have better air flow. I heat the house with a pellet stove and the box fan filters both move the warm air around plus filter it. With the fans running my wife's allergies disappear as she stops sneezing within an hour of the fans running.
Larger filters are definitely better - as you mentioned more air flow, but like you said, they cost more and take up much more space. I'm thrilled to hear your wife's allergies are better when running a filter - win!
Well, I'm seeing this 2 years after it was made, but I think I am going to try using some furnace filter media. Won't do what the higer merv rating ones will do, but I have a high air flow barrel fan, and I can basically just cut a piece and drop it on the back-the fan will suck it tight. We'll see what happens! Thanks for the video!
Thak you Joshua for doing the research and work for us. I wondered about the motor heating up too. Now I know! I'm going to the store tomorrow and get a filter. Thanks again for doing the work for us
Great scientific approach on these questions! I was surprised, though, that you didn’t use a device to measure particulate matter, e.g., an AQI monitor. This would have allowed for you to record the actual amount of smoke particles and specifically how long it takes for the filter-fans to clean the air to a given level.
Great video thanks. Actually I just put my filter up against the rear of the fan and it gets drawn tight against the fan without using tape etc. Not perfect air tight fit but seems to work.
Thank you for the comparisons! I live over a highway, so I always tape a filter (rated for "smog" as well as the other categories) against my window fans, with the idea that something is better than nothing! I notice a difference, and especially think about all of the dark dirt accumulating on the filter, which is probably mostly smog and at least that portion of it didn't make it to my lungs! Your experiments made me wonder if there is a way to enhance the filtration in a window air conditioner. Do you have any ideas, or do you think taping a good filter (that has proven to allow good airflow with a fan) to the outside of the front intake of the a/c would do some extra filtering and be worth it? (I might try it and report back to you if I see any pattern of dust/dirt accumulation on the filter, and if the normal filter a quarter inch away from it inside the machine ends up needing fewer cleanings.) (I'll also let you know if it seems to make the unit labor or get too hot or anything.)
Thank you for the video. The flex model with inserted filter is not yet available in Canada. 4:50 motor temp test. NB: some comments suggest 4 in or 5 inch wide filter.
Been using a similar setup for years and haven't burned the house down yet. Like the idea of the C channels to hold the filter. I'll have to do that some day.
Hey Josh, great video! Thank you for taking your time to do this video. Thank you also for putting link for the J channel, really appreciate you. Take care!
Lasko makes a fan now with air filter holder built on, seen them in Menards. Not sure if it comes with a filter or what their directions are for MERV acceptabiltiy.
I made it - you can check out how here: ruclips.net/video/9vJk5BM8xUo/видео.html Additionally, some companies are now making them with built in air filter holders: amzn.to/2XKlWXB
Great Video, I use the filter on the back of the fan I notice it works better for me, Question ur thoughts , I put filter on back of fan with the air flow arrow pointing towards the front of the fan because it is sucking the air through the back and out the front does that make sense??...Thanks JJ
Wow, there really is everything on the internet. well done. I just put one of these together. the possibility of the motor overheating occurred to me and i thought a solution might be to cut a round hole in the filter to allow unrestricted/unfiltered airflow into the rear motor vents. Seems like this might be unnecessary. The fan has 3 speeds, i’ll likely run it on the lowest, which seems to push plenty of air. i figure the motor “strain” on speed 1 with a filter is more or less equivalent to fan on speed 3 with no filter.
And you'll notice a definite airflow difference when you change out a dirty filter for a clean one too. We typically leave them on medium, sometimes high, and haven't had any issues.
I think a concern is the restriction of air movement that heats up the fan motor. I've seen solutions to this where a box of air filters are used so that there are four areas for air to travel instead of your one filter. I'll be building one for my shop to reduce the dust. It's brutal in a wood shop. The air filters sold at the store for shops is just too expensive. Then buying the filters becomes another issue.
If you have the space, then yes the "box" of air filters will be a more efficient solution - I use them in our bedrooms on top of dressers so I was looking for something compact.
I'd still recommend the MERV13 or equivalent - but check the filter packages/information and decided which level of filtration you're willing to pay for!
So should the arrow go in the DIRECTION of the airflow? Or opposite? If I put the filter on the back should the arrow be pointing towards the front of the fan where the air is coming out of ? How come they don’t work backwards?
hi thanks for the great idea. I just ordered two fans. Can you please tell me which are the two best affordable filters that I should consider purchasing for this. Please and thank you
Anything that is 20x20x1 MERV 13 rated or equivalent. There is a link in the description for a 4 pack on amazon - but you can find these at any home improvement store or big box store too.
Best configuration is a 4 sided cube. 5 sided cube will give you a better cad but 4 on the floor is the cheapest and most efficient way to do it unless you plan to hang it. 4x cube, 1x cardboard and then the fan... Set it on the floor and change your filters after about 6m
Excellent and clearly detailed demo video. Can you give an estimate of how often the filter needs to be changed? What are you using to attach the filter to the fan?
I change them every 8 weeks - just depends on the time of year - how much pollen or dust is in the air - change them as often as you change your whole house filter. You can check out the build video here: ruclips.net/video/9vJk5BM8xUo/видео.html
Is it safe to use a 4" filter rather than a 1" filter? I'm using the fan in a window overnight (to cool off my apartment vs. A/C) and I live on a heavily trafficked street. The fan blades get coated with oily dust w/out a filter.
@@GanderFlight Thanks, Joshua. Also, I appreciate your detailed and methodical approach to your "research." It takes patience, lotsa' time and knowing the things that are important to check for.
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You will get a lot more airflow if you use 4 inch thick filters instead of 1, they also last longer. You can prevent the fan from drawing air from the front by adding a ring around the fan blades as close as you can, I recommend something rigid so it can’t be moved by the airflow overtime. I’m currently designing a filter model that uses 2 MERV 13s for much better filtration, and I’m also going to add a thin washable pre filter so that the more expensive filters will last much longer
Nope - just something that has the controls on the top or front and the power cord coming out of the bottom so that the filter doesn't interfere with either function.
Bigger filters are going to be better - just depends on how much space you have for this setup -- in our bedrooms we didn't have that much space on top of the dressers.
I bought a lasko fan with a 20 x 20 x 1 filter, I was able to cut out a small piece of the filter, only around the motor just to make sure the motor doesn’t overheat.
I have not. However, it does depend on how often you replace the filter - there is a significant air flow difference after the filter has been used constantly for weeks on end - which is good, it means its doing its job.
If there are concerns about constraining the air flow and burning out the motor, create a surface area with more surface area, such as a Cube of filters, using 5 filters.
found this video from a This Old House video on making a filter using 4 filters fitted into a cube with a piece of cardboard and a box fan. Any idea on if its worth doing more filters/lowering air resistance on the box fan? Really appreciate the experiments you performed. I think This Old House said with 4 MERV 13 filters on a box fan that you could move 900 cfm on high speed, any idea if a single filter causes it to move less or maybe it's just not worth it to have that many filters on a single fan?
I haven't done any testing with that setup - for me the footprint was too large and bulky for where I need them so I never considered it a viable option.
Every time I've tried doing this with a setup like you're showing at the beginning of the video the fan motor Burns out doesn't last very long I tried different fans too.
Sorry to hear that - we've used the same two fans for over 5 years this way. Maybe try Lasko's commercial version that comes as a package: ruclips.net/video/88ZYnSid3g4/видео.htmlsi=WyVlmXavsS-6Tyt0
I did some testing with my DIY air purifier. I used a 200W wall fan of 400mm (uzman ksa-400 15.7") and a stack of 405x405mm filters: prefilter (thin foam + MERV11 filter 2" thick) - carbon filter (1") and 2" HEPA filter (MERV17). Built a simple wooden box to fit everything in. At full speed with ambient temperature of about 18 degrees C it only warmed up to 23-24 degrees C after 30min running as per the thermal imaging camera. I used the fan to pull air through the filters to keep the motor clean. The airflow was enough to cool the motor, even though it was quite a load. The advantage of a prefilter is you keep the more expensive ones (carbon and hepa) cleaner so you don't have to replace them as often. The foam layer can be vacuumed off for larger dust particles (also a shop vac with HEPA filter). Pollen are about 2.5-200 micron in size, average about 25 micron. The MERV11 will filter 70% of 2.5 micron and most of the >10 micron size. A box fan may not have enough static pressure to pull air through a filter stack though, you'll have to increase surface area to compensate. ie either thicker filters/larger pleats or more square meters/ft.
Great video, well articulated and practical. It almost made me want to huff. On another note, I plan to do the same but with carbon filters in hopes to get smell out of a small room. Those box fans are awesome and about a quarter of the price of others.
Hi there, do you have any ideas how I can add a filter to my smaller but powerful Honeywell fan? It's like a Vornado fan with a rounded back. I have anir purifier in my room but I'd like to kick start the clean air with my fan. My room gets really dusty and I'm disabled so I'm trying to get more clean air. Yes I've actually cleaned too. ☺️
i have a honeywell also and i am goint to purchase a 20 x20 by 1 in filter and cut it to fit the inside of my honeywell replace the black foam filter with it cut away the card board on the filter and then measure out what i need mine is like 4 in wide by 24 in tall so yea i thing it will work !
The problem isn't so much the fan overheating when the filters are fresh - it becomes an issue as the filters get dirty and they restrict more airflow. Also, restricting airflow is wasting power, since the fan draws the same energy whether the airflow is restricted or not. Without the restriction the fan could circulate - and filter - more air for the same power consumed, and you'd get more filtered air. The solution is to build a box out of air filters, which you can just tape together with duct tape. Get 4 appropriately-sized filters and a matching piece of cardboard and build a 5-sided box with one end left open for the fan. Place the cardboard piece on the ground and build the box around that. Now you have so much surface area for the air to pass thru there will be virtually no restriction to the airflow, so no electricity will be wasted and the fan will be able to filter more air in a shorter period of time than it can manage with one filter. You also won't need to change filters as often. Only real downside is it takes up more space and isn't exactly pretty, although you could always build or repurpose some kind of box or cabinet to hide the whole setup in.
Yes, the box of filters would be overall better - but the amount of space it takes up and the aesthetics are the real killers - I currently have these set up in our bedrooms setting on a dresser - couldn't do that with the air filter box.
@@GanderFlight It does take up more space. You could get creative and possibly use narrower filters for the ‘sides’ of the box - not sure what dimensions HEPA furnace filters come in. Would still allow you to more than double the surface area of the filters.
Putting filter before depressurizes air, putting filter in front pressurizes air between the filter and the fan...Hence putting filter in front causes higher temp as air was pressurized...however, it is also important to consider the velocity of air that passes through the filter, which determine how tight or loose the particle trapped in the filter. This is even more important when using a box (CR BOX), which further reduces the velocity of air passing thru, on top of the dirty side of the filter are actually facing outside. box fan has a very low static pressure tolerance, which need to be compensated by adding larger area, that will done very little in circulating air throughout a room...
I'm sure they'd be more effective than not having them, but unless the entire room is sealed except for the filter I think youd be better off forcing the air through with a fan.
I just balled up some aluminum foil and used that as a lil stand under the fan in the front so the fan sat more up than facing the floor because of those plastic stands in the back
Been doing that for 30 years. no issues. although I put the fan on the back and tape off the corners of the box fan outside the radius of the fan blades, that will fix it.
I wouldn't worry about it, given your measured temperatures. Assuming the motor windings are class F, they would be rated for up to 155°C (311°F) before insulation breakdown starts to occur. Even if the motor windings were the worst case of class A, they would still be rated up to 105°C (221°F). These ratings come from IEC 60085. Insulation breakdown is the primary concern with motor and transformer windings. If the insulation breaks down the motor winding turns will short circuit and could possibly cause a fire. The internal over current protection or branch circuit breaker panel should kick in if that were to happen.
What are those things that you have attached to the fans that you slide the filter in and out of where do you get them and what size I've been looking for something like that
been running 2 of these in my homes since 2004 no issues at all they are safe and effective change the filter as needed and tape a new one on 45 seconds and go..
Define the terms back and front in relation to the fan. I suggest using "intake" and "exhaust" instead of front and back, to make it clear which side of the fan you're talking about. So is front the intake or exhaust side of the fan?
This was a very well done video. I recently purchased some merv 13's and am looking forward to trying to build a couple filters. Thanks for the scientific testing video to demonstrate the heating question! I'm gong to thumbs up and subscribe to support your helpful work!
If Merv 13 work with a box fan then they are not true merv rated filters those cheap box fans are not powerful enough to pull air through true merv 13 but you'll see for yourself maybe I'm wrong 😁
@@covidinfectedmonkeypox6775 Ok I guess we'll see! They weren't cheap box fans. They were at least 15 bucks! I hope it sort of works to some degree? I'll try to give an update when I try it out!
you but the filter on back of fan than do you sit the fan in the window like normal or do you put it in backwards so it is sucking air out of the house?
Does the fan still work to keep cool, or is it only a circulator of filtered air? I use it at night to keep the bedroom cooler for sleeping. You are a good instructor.
An inexpensive air quality meter measuring small particles and voc would have provided quantifiable results. I have a similar setup but added a carbon activated filter
The reason you put the filter on the Intake side. Is you want to filter the dust out before the fan. Just like your Heating and A/C unit. A filter doesn't block air flow that much.
Watch all the Box Fan Air Filter Videos here:
ruclips.net/p/PLAriVJ-zrwINFsLm9NWBSUFdyV1x3ebqZ
🔸 DIY Air Filter | Box Fan Modification | Cleaner Air for Your Home from Pollen or Wildfire Smoke!
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🔷 Menards: www.menards.com/main/heating-cooling/portable-fans/lasko-air-flex-20-air-purifier-box-fan/ff305/p-7720120058360405-c-12727.htm
🔷 Home Depot: www.homedepot.com/p/Lasko-Air-Flex-20-in-3-Speed-Air-Purifier-and-Room-Fan-FF305/315516663
🔷 Walmart: www.walmart.com/ip/Lasko-Air-Flex-2-in-1-20-inch-Box-Fan-and-Air-Purifier-in-One-with-3-Speeds-FF305-White/473758982
🔷 QVC: www.qvc.com/qvc.product.H232553.html
🔷 Boscov’s: www.boscovs.com/product/lasko-air-flex-2-in-1-20in-box-fan-air-purifier/763003
🔷 Wayfair: www.wayfair.com/Lasko--Lasko-23.2-Box-Fan-FF305-L447-K~UNW10066.html
🔷 Amazon: amzn.to/3NhkSlh
Thanks for the video!
The advantage to placing the filter on the back, is that the filter stops the usual build-up of dust and dirt on the fan blades (which .. over time, puts more drag on the blades which may heat the motor up a little with extra work and less airflow). Meanwhile, putting the filter on the front stops the dust/debris escaping, which slows the exit airflow a little and (admittedly, slightly) encourages the build up of dust on the blades and doesn't protect the motor. So for single filter setups, I'd recommend the back mounted filter, and you get the aesthetic benefits that are mentioned in the video and unobstructed access to any front-panel controls.
As found in the video experiment... the amount of filtration should be (for all intents and purposes) identical if the fan speed and filters are the same. However, if the experiment ran for months until the filters were clogged and needed replacing... that story might be a little bit different.
Taking it further.. two filters of differing types:
A lot of wood workers, noticing the sawdust buildup accumulating in their workshops are putting filters on both the front and back of fans (Google/RUclips search: "DIY workshop air filter", and you'll get the idea). These usually involve two or more filters, with the typical air filter for the larger dust/particles/fibres on the back and another, 5 micron HEPA filter (or something similar) on the front. Naturally, this filters the air to a much higher quality, but also increases the cost of construction and ongoing maintenance. While you want a nice sealed "bottle neck" around the fan itself for efficient airflow, it's also better if you have a slightly larger filter than the fan on both sides as this reduces the "back pressure" the filters will place on the motor.
If safety is your biggest concern, the best things you can do:
1. Keep your house as clean as possible... the less dust your filters are exposed to, the longer they'll last, and airflow will be less restricted. Put simply, there's less to catch on fire if there's a problem, and it's a situation that's less likely to cause a fire too. :-)
2. Clean and replace the filters regularly, (or as needed in times of low air quality). Clean any build up on the fan blades and suck any dust out of the motor with a vacuum.
3. Electrical safety. If you're enclosing a fan inside a box, then having a dedicated "safety switch" which (depending on the type) is usually either a Ground Fault Circuit Interrupter (GFCI) or Residual Current Device (RCD). These devices create an automatic way to cut the power to the fan in the event of a fault. Differing laws and electrical systems are found in differing countries, but research how things are done in your relevant area or talk to your local qualified electrician and they'll give you appropriate advice. However, we can buy RCDs in Australia for around $20-30 in our nearest hardware store. Installation is easy. Plug the RCD into the wall, and then plug the fan into the RCD. Turn on the fan and make sure the switch trips the power by pushing the "Test" button, then hit the "Reset" button to turn the power back on.
I hope this helps someone out there in these crazy times!
Thanks for the helpful and well thought out comments!
Yeah, filter on the back is safer in the long run. Esp if used in a woodworking shop
Ya makes way more sense on the back nearly every fan ive had that failed was due to dust collecting on the motor and building up till it has to much resistance and fails. Also i never run it on max speed and the motor stays cool enough within spec.
Thank you for this information its what i was needing to know :)
If you put it on the front, the air won’t go through and it’ll start blowing out the back of the fan
I'd like to see @Project Farm test this against some top rated air purifiers. 😲
What a great idea- I’ll go leave him a message!!!!
Yes!
@@GanderFlight any update?
@@rickfrank7934 I left him a comment - but didn't hear anything - nor do I expect to. Maybe we'll see a video sometime. Head over and leave Todd a message too! Maybe if we get enough folks suggesting it he might indulge.
He has done a video on HVAC filters though: ruclips.net/video/RkjRKIRva58/видео.html
Best reason to put FILTER ON BACK is because you're filtering the air BEFORE the dust gets to the fan motor. If this was near a dust source that can build up (like saw dust) then the dust can not collect on the back of the motor because the filter collected the dust first.
This reason alone is important enough to make it the preferred method.
Thanks for the perspective!
Excellent Point!
Great video! I saw this idea, (same as yours), some months ago. The idea bounced around my head for a while and I decided to build one. One $18.00 Walmart fan and a 20"X 20" filter, the most expensive one Lowe's sells, taped it on securely and it has been running constantly for 6 months or so. The fan motor hasn't gone south but I change the filter every 2-2.5 months. That worked so well, I got another fan and filter and some duck tape. That one has been running for nearly 3 months. We have a HEPA filter in the bedroom due to my wife's allergies and my COPD. The fan filters do make a difference but I have no way of testing its efficiency.
Glad theyre working out for you!
*Works great with **Fastly.Cool** , exactly as described. Love the fact that it can push, pull, or exchange air with the push of a button. The remote is a nice bonus too!*
Not sure what fastly cool is and your link just goes to a general amazon page.
I’ve used this method while replacing my attic insulation in mid summer.
Not only did it filter out the insulation particles it still dropped the attic temperature by 10 degrees.
This works and I’m planning to use it to take some of the strain off of our home furnace. 👍👍
Thats a good use for that project!!
Great tip. I have a box fan with a filter on the back 7 micron filter in my woodshop . I turn it on at the end of the day to help clean the air of wood dust. I have it on a timer. It runs for 3 hours.
The timer is a great addition for an application like yours!
Great video! While the Corsi Rosenthal box seems better when it comes to performance, this single-filter version is MUCH more portable. I'm pleased to see that the fan motor didn't heat up that much. If you're really that concerned about this issue (or if you want to reduce the electricity usage or make the filter last longer), you can connect the filtered fan to an electrical timer and set it to automatically turn on and off every half hour.
The timer is a good idea Jason!
I love how straight to the point the video is. Thank you.
You're welcome!
I have been using this setup in my metalworking shop since 1989. Never had a problem. I just use a box fan, a filter, and a couple of bungee cords. The Walmart box fan has to be replaced about every decade. I always get the cheapest one. I wish I could find one of those old all metal box fans from the pre ‘80’s. Those things ran forever.
I think my dad still has on of those metal box fans in the garage - simple and effective and still going strong!
I like your bungee cord idea. I don't feel like getting too fancy but I also don't want to deal with tape. This is the perfect solution and easy too! Glad I read your comment! :)
I agree with you, they last a long time and can run for years with a filter. My little dog liked to sleep in from of my box fan air filter. It was kept on 24 hours a day for over 3 years. The fan still works fine. I made a video of my little wooden clamp with a magnet and handle I made to attach the filter. "DIY $6 Magnetic Dust Fan Filter air cleaner for Home & Shop"
Watched the video - cool idea using the magnet!
Thank you for the effort put into this video, it’s greatly appreciated
My pleasure!
I got a filtrete 1900 air filter on my box fan and it helped tremendously with my allergies!
Glad to hear it!
Great testing! Good to know what the temps are! If people are worried about static pressure and strain on the motor they could get larger filters. I think you can get 20"x20"x2" which would double the filter surface area so more air will pass through. The larger the filter media the longer it lasts before clogging to so that is an advantage. I have that exact fan and been using it in a custom wooden box for 3 years. I made mine for a 20"x25"x5" filter which is 5x the surface area of a 20"x20"x1". I can run the fan on medium and get more airflow in the room compared to the smaller filter on high with all that extra surface area passing air. If you really want the motor to last long and quiet the fan down a little, I put a link to a video on balancing the box fan blade below. The bearings will have less stress on them and it will be less shaky when running but I use mine on medium speed so I'm already putting much less strain on mine so I never tried to balance the blades. ruclips.net/video/moo95i_6QZs/видео.html
Super helpful, thanks Practical Guy!
I just build a cube using four filters, the fan, and cardboard for the base. 13 merv 20x20 x2. Wow! Amazing filtration. Seems to be helping my COPD person.
@@pattip1413 That is a lot of filter surface area going with the 2" filters! Just slightly more than my 20"x25"x5". Sounds like its doing a great job for you and you'll need to change the filters less with that much filter dividing the air going through the box!
Hi, great videos. I was wondering if you had any DIY ideas to stop second-hand smoke from coming into an apartment? I already have the filter fan.
THANK YOU for the deep dive on this! I just ordered a $160 air filter, and am having 2nd thoughts. I did this a few years ago, and I noticed one thing: When you put the filter on the front, fan blowing at it, a whole bunch of air bounces right back at you from the rear!
Definitely better to put the filter on the back, and you can seal the edges with painters tape and place a shroud on the front to decrease backflow - check out the diagrams here: en.wikipedia.org/wiki/Corsi%E2%80%93Rosenthal_Box
@@GanderFlight Cool! That would really kick some ass. LOL If I do it again, I'll do that. Thank you.
Perty neat video Sir. You obviously put alot of time & effort into this project. Even the amount of time you spent on just the editing is outstanding. Good job!
Thank you very much!
1 advantage to having the filter on the inlet (back) side is the same reason furnaces are built that way: it keeps the motor windings cleaner which reduces fire/smolder hazards from dust build-up.
Agreed.
well done Josh, we appreciate your efforts and time it took for these tests! I"m going to make a fan/filter combo now b/c of this!
Enjoy!!!
Great Video ! if u Want to Add a Measure of Safety and don't want a Paper filter Slammed up tight against a hot motor. Space it away from the Rear of the Fan unit by a Few inches using Sheet metal and a Hvac Filter Rack.
Thanks for sharing the option :)
Thanks for the experiment. I have put a wifi switch with cloud timer in it. It is a little bit fancier. So, every two hours and stop for an hour (whatever you like for cool down the fan) around $10 to $15. But when your son's nasal allergy get improve much better, that makes me starts to make one for every room.
I like the additional customization! You could also do that with a standard outlet timer as well!
What’s a cloud timer? I have WiFi switches and receptacles but it’s all managed in the app nothing on the cloud.
Cloud just mean that the app store your timer setting in a server somewhere we don't know. Actually not quite knowing that my wifi switch timer info on the cloud or in the app or in the switch itself.
Run it for 4 months now, and I put have put a UV light and hide behind the filter against the wall for extra sanitizing and no direct UV light exposure to me. But that is really good for cleaning the mold (even covid) in the air.
@@siulungleecan you make a video on the setup?
I remember in our high school wood working/ construction class my teacher had several of these spread around his classroom to help keep the wood dust down. It actually helped tremendously. He did have a homemade dust collector system he rigged up with pvc pipe and an old car wash vacuum cleaner he put outside he had attached to the various saws that would automatically kick on whenever the equipment was turned on. Our school district was too cheap for a true dust collector system and air filtration. Luckily the new clean air regulations in my state got him a much needed remodel for his classroom. He said that in 1996 the high school finally got modern hvac systems in the classrooms so most of the teachers were throwing their old box fans out he said that he , the metals teacher and the automotive teacher collected them and attached brackets to them to make filtered air machines for their classrooms. I always admired him for collecting things other people were throwing out. His philosophy was to reuse, renew, and recycle as much stuff as possible.
Sounds like a resourceful guy!
Great video. I am looking for a CHARCOAL air filter because my main concern is VOCs (super small particles like fire retardants in rugs. formaldehyde in mattresses. inorganic clothing ink dyes off gassing etc)
Will these filters work? Or is the a 2in1 hepa / charcoal filter? thanks
I do not know the answer to your question, you'll need to do some further research yourself.
Nice experiment. I have been using this system to remove dust from my garage work area when I have been doing wood work. I only run the fan with the filter for maybe several hours during and after I generate dust. I have always put the filter on the back (intake side) and it certainly clears the dust from the air. Also tried it in the house during pollen season and it also seems to work. The problem is that the fan makes noise and my wife doesn’t like it. Been using Honeywell or 3M brands both rated for dust and dander I get at Home Depot. No MERV rating provided on the packaging.
Yeah Home Depot made up their own rating system. Merv 13 is equivalent to FPR 10
I just bought a Lasko brand fan with a filter that goes in the back. I'm not as crafty as you, so it was $60 well spent. Thank you so much for the idea! Love your videos.
I think its awesome that they've started making a version with the filter holder - definitely looks more aesthetically pleasing than the DIY version.
I truly want to thank you My husband wh is 81 early emphysema asthma and we have cats we wee facing the hard reality that we might have to get rid of the cats I was exploring HEPA filters and found your video. I was thinking of making my own and you showed me that I'm not crazy. Again Thank you!
Absolutely welcome!
this is a good enough test. You covered enough bases to prove your point. Been using box fan filters for over a year now. MERV 5 and now MERV 8 filters. I own a cat and a couple of my grandkids have cat allergies- the box fan filtering makes a HUGE difference... according to them. Project Farm would be proud :)
hahaha - thanks -love Todd's videos!
I bought about a $50 Lasko fan where you clip a 1 inch thick filter on the back, so I suppose since a fan company does it that way they must have tested it in their development phases. Thanks for a great video!
I've since gotten one of those Air Flex versions too and really like them.
We use this setup in my sons’ room and it is good. In my room I use a Winnix air purifier with a HEPA filter and for allergies that works best but both are impressive and helpful. I feel better after seeing your video.
The white noise of the fan is a side benefit to aid in sleeping!
Very nicely done review. Simple, straight-forward and informative. I think you put a nice balance between "scientific" results and real-world application. Important also, which many other experimenters tend to neglect, was the ambient temperature. ....you measured it (thanks).
.
Thanks for your efforts, thanks for sharing.
You are most welcome! Thank you for watching and taking the time to share your kind comments - hope you found some value in the information.
I did a search looking for the method, and safety of a box fan filter. Thank you
You're welcome!
Excellent video - Because of the Chinese Wuflu 1 year ago I made 3 box fan filters except I used 4 inch thick filters & I used MERV 13's that filter viruses from the air.. The 4 inch are quite abit more $$$ but they last longer and have better air flow. I heat the house with a pellet stove and the box fan filters both move the warm air around plus filter it. With the fans running my wife's allergies disappear as she stops sneezing within an hour of the fans running.
Larger filters are definitely better - as you mentioned more air flow, but like you said, they cost more and take up much more space. I'm thrilled to hear your wife's allergies are better when running a filter - win!
appreciate your dedication and commitment to this experiment! Thanks!
My pleasure!
Well, I'm seeing this 2 years after it was made, but I think I am going to try using some furnace filter media. Won't do what the higer merv rating ones will do, but I have a high air flow barrel fan, and I can basically just cut a piece and drop it on the back-the fan will suck it tight. We'll see what happens!
Thanks for the video!
Good luck!
Thak you Joshua for doing the research and work for us. I wondered about the motor heating up too.
Now I know! I'm going to the store tomorrow and get a filter. Thanks again for doing the work for us
Great scientific approach on these questions! I was surprised, though, that you didn’t use a device to measure particulate matter, e.g., an AQI monitor. This would have allowed for you to record the actual amount of smoke particles and specifically how long it takes for the filter-fans to clean the air to a given level.
Wasn't the scope of the question I was trying to answer
Great video thanks. Actually I just put my filter up against the rear of the fan and it gets drawn tight against the fan without using tape etc. Not perfect air tight fit but seems to work.
Yes that definitely works! Just causes issues when you turn the fan on and off everyday.
Thank you for the comparisons! I live over a highway, so I always tape a filter (rated for "smog" as well as the other categories) against my window fans, with the idea that something is better than nothing! I notice a difference, and especially think about all of the dark dirt accumulating on the filter, which is probably mostly smog and at least that portion of it didn't make it to my lungs! Your experiments made me wonder if there is a way to enhance the filtration in a window air conditioner. Do you have any ideas, or do you think taping a good filter (that has proven to allow good airflow with a fan) to the outside of the front intake of the a/c would do some extra filtering and be worth it? (I might try it and report back to you if I see any pattern of dust/dirt accumulation on the filter, and if the normal filter a quarter inch away from it inside the machine ends up needing fewer cleanings.) (I'll also let you know if it seems to make the unit labor or get too hot or anything.)
Experiment and let me know - I'm not sure how that will affect the air conditioner unit.
Thank you for the video. The flex model with inserted filter is not yet available in Canada.
4:50 motor temp test.
NB: some comments suggest 4 in or 5 inch wide filter.
👍
Bummer about the Flex not being available in Canada.
Been using a similar setup for years and haven't burned the house down yet. Like the idea of the C channels to hold the filter. I'll have to do that some day.
👍
Hey Josh, great video! Thank you for taking your time to do this video. Thank you also for putting link for the J channel, really appreciate you. Take care!
No problem!
Lasko makes a fan now with air filter holder built on, seen them in Menards. Not sure if it comes with a filter or what their directions are for MERV acceptabiltiy.
I've seen them too - they weren't out when I did the original build on these but it gives some validation on the DIY project.
Hello. Thank for the video. I was wondering what box fans you use as I noticed you were just sliding the filters on and off?
I made it - you can check out how here: ruclips.net/video/9vJk5BM8xUo/видео.html
Additionally, some companies are now making them with built in air filter holders: amzn.to/2XKlWXB
@@GanderFlight Thank you for your response 🙂
Great Video, I use the filter on the back of the fan I notice it works better for me, Question ur thoughts , I put filter on back of fan with the air flow arrow pointing towards the front of the fan because it is sucking the air through the back and out the front does that make sense??...Thanks JJ
Yup you've got it correct!
@@GanderFlight Thank You for the reply..
Lots of effort went into this video. Good job.
Thanks for watching!
A good test would be to test wattage draw on the fan with and without the fan and compare it to the rated power.
That would be a good test to measure.
🙋🏻♀️Hi Josh ! How did you secure the filter and which way did you affix it according to the arrows ???
hello! I think I saw a comment on the build video so I'm assuming this question was answered? If not let me know!
Wow, there really is everything on the internet. well done. I just put one of these together. the possibility of the motor overheating occurred to me and i thought a solution might be to cut a round hole in the filter to allow unrestricted/unfiltered airflow into the rear motor vents. Seems like this might be unnecessary. The fan has 3 speeds, i’ll likely run it on the lowest, which seems to push plenty of air. i figure the motor “strain” on speed 1 with a filter is more or less equivalent to fan on speed 3 with no filter.
And you'll notice a definite airflow difference when you change out a dirty filter for a clean one too. We typically leave them on medium, sometimes high, and haven't had any issues.
Forest fire smoke is irritating tonight. I just put my kit together. I already feel a difference. 👍🏼👍🏼
Glad to hear it!
I don't wanna grind ur gears but what if you had the motor vent holes open would the temp be sort or cooler?
It's quite possible that might cool it down some.
I do some painting and the smell is pretty strong at times. Would you think this will help with the smell of paint?
I'm not sure - give it a try and let us know!
Thank you for that video. I just found out I could build this purifier and was wondering of the safety. Very useful 💖
You are welcome!
I think a concern is the restriction of air movement that heats up the fan motor. I've seen solutions to this where a box of air filters are used so that there are four areas for air to travel instead of your one filter.
I'll be building one for my shop to reduce the dust. It's brutal in a wood shop. The air filters sold at the store for shops is just too expensive. Then buying the filters becomes another issue.
If you have the space, then yes the "box" of air filters will be a more efficient solution - I use them in our bedrooms on top of dressers so I was looking for something compact.
What filter for city, apartment dweller? Not in any smoke zone in Raleigh NC. Is Merv 13 good for anyone, smoke or non smoke environment?
I'd still recommend the MERV13 or equivalent - but check the filter packages/information and decided which level of filtration you're willing to pay for!
So should the arrow go in the DIRECTION of the airflow? Or opposite?
If I put the filter on the back should the arrow be pointing towards the front of the fan where the air is coming out of ?
How come they don’t work backwards?
In the direction of airflow - so always pointing forward from the fan.
hi thanks for the great idea. I just ordered two fans. Can you please tell me which are the two best affordable filters that I should consider purchasing for this. Please and thank you
Anything that is 20x20x1 MERV 13 rated or equivalent. There is a link in the description for a 4 pack on amazon - but you can find these at any home improvement store or big box store too.
@@GanderFlight thank you
Best configuration is a 4 sided cube. 5 sided cube will give you a better cad but 4 on the floor is the cheapest and most efficient way to do it unless you plan to hang it. 4x cube, 1x cardboard and then the fan... Set it on the floor and change your filters after about 6m
True - also takes up a TON of floorspace :)
Such a wonderful help for so many people. Love it!
Thanks for watching!
Excellent and clearly detailed demo video. Can you give an estimate of how often the filter needs to be changed? What are you using to attach the filter to the fan?
I change them every 8 weeks - just depends on the time of year - how much pollen or dust is in the air - change them as often as you change your whole house filter. You can check out the build video here: ruclips.net/video/9vJk5BM8xUo/видео.html
Is it safe to use a 4" filter rather than a 1" filter? I'm using the fan in a window overnight (to cool off my apartment vs. A/C) and I live on a heavily trafficked street. The fan blades get coated with oily dust w/out a filter.
Yup - you'll end up getting more airflow through with the wider filter too.
@@GanderFlight Thanks, Joshua. Also, I appreciate your detailed and methodical approach to your "research." It takes patience, lotsa' time and knowing the things that are important to check for.
🚨🚨!!NEW!! 🚨🚨If you’d rather purchase a ready made unit, Lasko now offers the Air Flex 2 in 1 box fan that includes a MERV10 filter and filter holder built in!
Amazon:
amzn.to/3L2u7Fm
Home Depot:
www.homedepot.com/p/Lasko-Air-Flex-20-in-3-Speed-Air-Purifier-and-Room-Fan-FF305/315516663
Mendards:
www.menards.com/main/heating-cooling/portable-fans/lasko-air-flex-20-air-purifier-box-fan/ff305/p-7720120058360405-c-12727.htm
You will get a lot more airflow if you use 4 inch thick filters instead of 1, they also last longer.
You can prevent the fan from drawing air from the front by adding a ring around the fan blades as close as you can, I recommend something rigid so it can’t be moved by the airflow overtime.
I’m currently designing a filter model that uses 2 MERV 13s for much better filtration, and I’m also going to add a thin washable pre filter so that the more expensive filters will last much longer
All great points - adaptable for many scenarios and price points.
Thanks for the idea. Knowledge is power. You've made us powerful.
I am going to try this with two modifications.
What are those two modifications?
What are you using for the filter brackets?
Vinyl siding J-Channel from the hardware store as seen here: ruclips.net/video/9vJk5BM8xUo/видео.html
Is there any particular bran I’d box fan that you would recommend?
Nope - just something that has the controls on the top or front and the power cord coming out of the bottom so that the filter doesn't interfere with either function.
Great video. Deserves more views. I appreciate all the time and effort!
Much appreciated! Thanks for the comment
Yep this weekend I'm going to go to the store and buy all the parts and start putting this into all my fans thank you so much
Enjoy and happy building!
4 inch filter, More surface area, which would be less strain on the motor?
Bigger filters are going to be better - just depends on how much space you have for this setup -- in our bedrooms we didn't have that much space on top of the dressers.
I bought a lasko fan with a 20 x 20 x 1 filter, I was able to cut out a small piece of the filter, only around the motor just to make sure the motor doesn’t overheat.
That's one way to do it!
Lol
Have you done a test with air flow using filter vs. without filter? How significantly is the power of the fan lowered with a filter?
I have not. However, it does depend on how often you replace the filter - there is a significant air flow difference after the filter has been used constantly for weeks on end - which is good, it means its doing its job.
If there are concerns about constraining the air flow and burning out the motor, create a surface area with more surface area, such as a Cube of filters, using 5 filters.
👍
found this video from a This Old House video on making a filter using 4 filters fitted into a cube with a piece of cardboard and a box fan. Any idea on if its worth doing more filters/lowering air resistance on the box fan?
Really appreciate the experiments you performed.
I think This Old House said with 4 MERV 13 filters on a box fan that you could move 900 cfm on high speed, any idea if a single filter causes it to move less or maybe it's just not worth it to have that many filters on a single fan?
I haven't done any testing with that setup - for me the footprint was too large and bulky for where I need them so I never considered it a viable option.
Every time I've tried doing this with a setup like you're showing at the beginning of the video the fan motor Burns out doesn't last very long I tried different fans too.
Sorry to hear that - we've used the same two fans for over 5 years this way. Maybe try Lasko's commercial version that comes as a package: ruclips.net/video/88ZYnSid3g4/видео.htmlsi=WyVlmXavsS-6Tyt0
I did some testing with my DIY air purifier. I used a 200W wall fan of 400mm (uzman ksa-400 15.7") and a stack of 405x405mm filters: prefilter (thin foam + MERV11 filter 2" thick) - carbon filter (1") and 2" HEPA filter (MERV17). Built a simple wooden box to fit everything in.
At full speed with ambient temperature of about 18 degrees C it only warmed up to 23-24 degrees C after 30min running as per the thermal imaging camera. I used the fan to pull air through the filters to keep the motor clean. The airflow was enough to cool the motor, even though it was quite a load.
The advantage of a prefilter is you keep the more expensive ones (carbon and hepa) cleaner so you don't have to replace them as often. The foam layer can be vacuumed off for larger dust particles (also a shop vac with HEPA filter). Pollen are about 2.5-200 micron in size, average about 25 micron. The MERV11 will filter 70% of 2.5 micron and most of the >10 micron size.
A box fan may not have enough static pressure to pull air through a filter stack though, you'll have to increase surface area to compensate. ie either thicker filters/larger pleats or more square meters/ft.
all great points - sounds like you had some fun experimenting too!
Yeah I never thought of that it'll help the allergies
Definitely helps running them while sleeping at night.
Great video, well articulated and practical. It almost made me want to huff. On another note, I plan to do the same but with carbon filters in hopes to get smell out of a small room. Those box fans are awesome and about a quarter of the price of others.
Good plan! The carbon filters should definitely help grab some of the odors.
Hi there, do you have any ideas how I can add a filter to my smaller but powerful Honeywell fan? It's like a Vornado fan with a rounded back. I have anir purifier in my room but I'd like to kick start the clean air with my fan. My room gets really dusty and I'm disabled so I'm trying to get more clean air. Yes I've actually cleaned too. ☺️
Try putting a filter as close as you can to the front of that fan since the back is rounded.
@@GanderFlight ok thank you!
i have a honeywell also and i am goint to purchase a 20 x20 by 1 in filter and cut it to fit the inside of my honeywell replace the black foam filter with it cut away the card board on the filter and then measure out what i need mine is like 4 in wide by 24 in tall so yea i thing it will work !
This is great. I was having that question, and you've done a great job answering.
Glad it was helpful!
Would a hepa filter be too dense and cause the motor to heat up?
Unsure
The problem isn't so much the fan overheating when the filters are fresh - it becomes an issue as the filters get dirty and they restrict more airflow. Also, restricting airflow is wasting power, since the fan draws the same energy whether the airflow is restricted or not. Without the restriction the fan could circulate - and filter - more air for the same power consumed, and you'd get more filtered air.
The solution is to build a box out of air filters, which you can just tape together with duct tape. Get 4 appropriately-sized filters and a matching piece of cardboard and build a 5-sided box with one end left open for the fan. Place the cardboard piece on the ground and build the box around that. Now you have so much surface area for the air to pass thru there will be virtually no restriction to the airflow, so no electricity will be wasted and the fan will be able to filter more air in a shorter period of time than it can manage with one filter. You also won't need to change filters as often. Only real downside is it takes up more space and isn't exactly pretty, although you could always build or repurpose some kind of box or cabinet to hide the whole setup in.
Yes, the box of filters would be overall better - but the amount of space it takes up and the aesthetics are the real killers - I currently have these set up in our bedrooms setting on a dresser - couldn't do that with the air filter box.
@@GanderFlight It does take up more space. You could get creative and possibly use narrower filters for the ‘sides’ of the box - not sure what dimensions HEPA furnace filters come in. Would still allow you to more than double the surface area of the filters.
This old house has a video for this
Putting filter before depressurizes air, putting filter in front pressurizes air between the filter and the fan...Hence putting filter in front causes higher temp as air was pressurized...however, it is also important to consider the velocity of air that passes through the filter, which determine how tight or loose the particle trapped in the filter. This is even more important when using a box (CR BOX), which further reduces the velocity of air passing thru, on top of the dirty side of the filter are actually facing outside. box fan has a very low static pressure tolerance, which need to be compensated by adding larger area, that will done very little in circulating air throughout a room...
Will smoke air filters be effective if you just put them on a window without a forced air set up? And have an exhaust window fan on the opposite side?
I'm sure they'd be more effective than not having them, but unless the entire room is sealed except for the filter I think youd be better off forcing the air through with a fan.
I seriously doubt it ( or very little) , you need the air flow 'forced' to make the filters really useful
Where did you get the side slots/ brackets to hold the filter
I just balled up some aluminum foil and used that as a lil stand under the fan in the front so the fan sat more up than facing the floor because of those plastic stands in the back
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Thank you! Love the popcorn smoker!
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Been doing that for 30 years. no issues. although I put the fan on the back and tape off the corners of the box fan outside the radius of the fan blades, that will fix it.
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I wouldn't worry about it, given your measured temperatures. Assuming the motor windings are class F, they would be rated for up to 155°C (311°F) before insulation breakdown starts to occur. Even if the motor windings were the worst case of class A, they would still be rated up to 105°C (221°F). These ratings come from IEC 60085.
Insulation breakdown is the primary concern with motor and transformer windings. If the insulation breaks down the motor winding turns will short circuit and could possibly cause a fire. The internal over current protection or branch circuit breaker panel should kick in if that were to happen.
👍 Lasko now makes this DIY fan as an option straight out of the box so they don't think its an issue either.
What are those things that you have attached to the fans that you slide the filter in and out of where do you get them and what size I've been looking for something like that
J channel from the hardware store - 5/8" - you'll have to cut it to length
If you don’t mind me asking where did you get the two back clips that holds the filters in place?
Its j - channel for residential home vinyl siding. Here's the build video: ruclips.net/video/9vJk5BM8xUo/видео.html
Thanks for all of your effort….much appreciated!
My pleasure! Thank you for watching!
been running 2 of these in my homes since 2004 no issues at all they are safe and effective change the filter as needed and tape a new one on 45 seconds and go..
Love it!
Define the terms back and front in relation to the fan. I suggest using "intake" and "exhaust" instead of front and back, to make it clear which side of the fan you're talking about. So is front the intake or exhaust side of the fan?
Front is exhaust.
This was a lot of work for you, and very helpful to me. Thanks so much for sharing!
You're very welcome Tracy.
This was a very well done video. I recently purchased some merv 13's and am looking forward to trying to build a couple filters. Thanks for the scientific testing video to demonstrate the heating question! I'm gong to thumbs up and subscribe to support your helpful work!
Thank you! Glad it was helpful.
If Merv 13 work with a box fan then they are not true merv rated filters those cheap box fans are not powerful enough to pull air through true merv 13 but you'll see for yourself maybe I'm wrong 😁
@@covidinfectedmonkeypox6775 Ok I guess we'll see! They weren't cheap box fans. They were at least 15 bucks! I hope it sort of works to some degree? I'll try to give an update when I try it out!
I use a Merv 5 on the back as a pre-filter and a merv 11 on the front as a final stage.
you but the filter on back of fan than do you sit the fan in the window like normal or do you put it in backwards so it is sucking air out of the house?
neither - we run this in the room with the windows closed - cleans the air within the room.
Does the fan still work to keep cool, or is it only a circulator of filtered air? I use it at night to keep the bedroom cooler for sleeping. You are a good instructor.
Yup definitely still moves air to cool - not as much as without the filter, but that’s to be expected.
An inexpensive air quality meter measuring small particles and voc would have provided quantifiable results. I have a similar setup but added a carbon activated filter
👍🏻 thanks for the suggestion
The reason you put the filter on the Intake side. Is you want to filter the dust out before the fan. Just like your Heating and A/C unit. A filter doesn't block air flow that much.
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