Best fan placement to move air through the house

[@keith819]

No joke, this is the old KZbin. Not over produced stuff, but a normal guy having fun and doing Science

[@backstabingpike]

Greedy fascist ruin stuff 😉

[@CHEDDAakaSWAY]

You hit it right on the head bro this has that 08 09 feel

[@supersuede91]

the Based KZbin

[@cutescarydolls]

having fan

[@Daurek]

@@supersuede91 i see bajs

[@Kuplung57]

This is how I like experiments on youtube. No nonsense, no 5 minutes blabla, just the experiment. Love it!

[@vitorvs]

But he didn't ask to like and subscribe, there is something wrong here. /s

[@1.4142]

I'm a huge fan of him.

[@parasahlawat27]

Pure practical, no theory!

[@wolfcounselor858]

@@vitorvs Not asking yourr listeners to hit the like and subscribe button is just wrong tho

[@Tdorf53185]

I bet, like me, you also hate recipes online that have 24 paragraphs about how they came to discover the recipe and their life story before they get to the recipe.

[@roberto3f84]

I am an Italian firefighter, this is the same principle we use to evacuate the fumes from the houses during a fire, the "cone" of air must cover most of the window opening

[@matthiasrandomstuff2221]

exactly!

[@nicktrousers]

cool!

[@tiporari]

@@matthiasrandomstuff2221 could you repeat your experiment with some simple ducting? Just foam board or something cheap and easy to throw together? I find ducting to be far more important than individual fan characteristics or performance.

[@tiporari]

@@matthiasrandomstuff2221 could you repeat your experiment with some simple ducting? Just foam board or something cheap and easy to throw together? I find ducting to be far more important than individual fan characteristics or performance.

[@Don.Challenger]

@@tiporari I had to vote you up that other you guy was getting more than you were.

[@Smagglet]

This guy is out here answering the questions everybody asks, but nobody feels like answering.

[@uuuultra]

now you know

[@jonrutherford6852]

Very good point. Thanks.

[@R3TR0J4N]

Exactly

[@bazooka712]

This is the Bernoulli principle.

[@lumilikha]

"This experiment is done" You earned a ton of fans with this experiment. Thanks!

[@matthiasrandomstuff2221]

and broke one!

[@Tr4wnet]

and money

[@LionelBercovich]

@@matthiasrandomstuff2221ahh the kind of puns I live for, can’t get any better

[@jameslast3192]

Me included!

[@C9chimichanga]

He doesn't have OnlyFans, he's got ManyFans.

[@Lexpert]

Just discovered your channel and gotta say I'm a fan.

[@javierborquez]

if you are a fan remember to stay 2 feet away from the window

[@AntiBellum]

Nice

[@matildajones6175]

🤣🤣🤣

[@razdankh]

​@@javierborquez 😂😂

[@fabianr1630]

🤣🤣

[@crapadopalese]

I love how you have no fluff in the video. Straight to the point. Wish all KZbinrs were like you.

[@FrogeniusW.G.]

True

[@barrioscorona215]

Right! Most KZbinrs have the 3 min intro music, 5 min explaining what they are going to show in the video, NordVPN segment, then 10 min later they finally get to what the description says 🤦‍♂️

[@Deinecraft]

@@barrioscorona215 I don't think it is right to expect the creatoers to not earning money through ads for their sometimes extremely high quality content, costs and effort they put in to their videos. With your favorite TV shows you also don't complain about intros. It is just part of the whole thing.

[@barrioscorona215]

@@Deinecraft You are right about the ads but for sure some KZbinrs have this over the top intro and that can be annoying. I like how this guy's immediately gets to the point. I don't mind the ads but what does bother me is over the top into with the music, then the sponsor and before you know it you're like 6min into the video. Like put the sponsor in the middle or something. Idk but I agree with you.

[@LightS_bRight]

​@@Deinecraft you mean KZbinrs have a right to beg. while real content creators ("aka artist") don't have to try.

[@Abodroc94]

This is science guys, this is the enbodiment of curiosity. This is the kind of things and people who got us out of the caves

[@freebornjohn2687]

It seems that a lot of people today want us to go back into the caves.

[@hannespi2886]

OUT OF THE CAVESSS

[@civilservant9528]

Abortions for some, tiny american flags for all

[@msm8698]

@@freebornjohn2687going back into the caves sounds kinda cool

[@freebornjohn2687]

@@msm8698 Cool as a weekend cave retreat with a support team, but going back to how people lived in the past few people would be up to it.

[@PastelComGini]

This kind of thing is why KZbin exists.

[@Mortequal]

This and cat videos

[@Anudorini-Talah]

no u gay

[@Mortequal]

@@Anudorini-Talah u right I'm no gay

[@tijujohn83]

Damn right

[@greedyboi8431]

@@Anudorini-Talah go away

[@WesBos]

Amazing, thank you for making this. It will solve so many family fights on the best way to cool the house

[@hpekristiansen]

Ice cube distributed evenly - one in each shoe.

[@seanedging6543]

If there’s one thing I learned about family fights it’s that they are never resolved via a KZbin video

[@thecloneguyz]

Bring cold air in low and send hot air out up high on the other side of the house

[@Bout_TreeFiddy]

prevent some murders too

[@thecloneguyz]

@@Bout_TreeFiddy I worked for David Horowitz in Seattle the Civil Rights leader are you related

[@RobWhittlestone]

As a physicist who worked in an office with no air conditioning, this was one of the experiments I had to undertake. Very often I would get to the office at 06.00 or 06.30 and the temperature in the office would be about 28°C. Outside air temperature was about 20°C at this time. Subjectively it was very noticeabble that blowing air out of one window enabled the other window to suck in cool air from outside. --> blow out is best, imagine the ventilator generates a "cone" of moving air which causes other air to also be moved. Aim for the largest vigorous moving part of the cone to be at the window. The next factor was whether closing the windows when the outside air temperature exceeded the inside temperature or whether to leave them open in the hope that there might be a breeze occasionally. --> This was conclusive - keeping hot air from outside out (typically 35°C in the mid afternoon) and the cool air in was best. The last objective factor was avoiding the sun heating objects (desks etc.) inside the office. For this, outside venetian blinds had to be adjusted so that sun did not shine directly on objects inside the office. This made a small but still appreciable improvement. One subjective factor is to use a ventilator to move the air in the office. Actually this should cause a miniscule temperature increase (the ventilator uses a motor consuming non-negligible amount of electricity converting into work, but SUBJECTIVELY the air moving over slightly moist skin feels cool. (But it isn't actually cooler, of course). I use these tricks also at home to ensure my house stays cool (we have no A/C) even though outside can be 39°C. Recently I had a 12° cooler house inside compared to outside. Whether in the office or at home I always make sure I can reliably measure the temperature in all required rooms and outside. Perception is subjective, thermometers are objective! All the best, Rob in Switzerland

[@rabenklang7]

I am no physicist, but woul'd moving air not increase the evaporation and so cool the evaporation surface/ object (in this case you), so it would not be a subjective feeling, but an actual cooling effect for humid objects?

[@VVayVVard]

​@@rabenklang7 This is true, and it's not just caused by evaporation. Air directly next to the skin is generally much warmer than room temperature (if ambient temp < body temp) which means that blowing air over the skin will replace warmer air with cooler air. This is why wind protection is important in cold weather; still air is an excellent thermal insulator, but it only works if you can actually prevent air next to the skin from flowing (which would otherwise quickly result in convective heat loss).

[@KelvinKamsg]

Born and living in a tropical, hot and humid country. I can confirm ventilator fans, or just moving air in general is really good for skin feel. I think slightly drafty indoors is something people living in temperate climates need to get used to and incorporate into their culture (global warming). I was so surprised when I holidayed in Europe and there were no fans (or air-conditioning) at all in the shared Airbnbs, it's fine in cold weather, but summer would be a broiling torture.

[@coolghoul9]

A lot of people think that no matter what, no matter how blazing hot it is outside, opening your windows will keep it the coolest inside

[@tragile9108]

@@rabenklang7 Yes but the room wouldn't be cooler, thus it being subjective (subjective as in relation to the room - as "what/who is it impacting" and not the general room temp) For example, chinchillas don't sweat like us thus air flow does not cool them down. So cooling down the whole room is needed. (As opposed to just cooling you down)

[@AlTheEngineer]

This is how KZbin used to be.... Useful videos, straight to the point, no sponsors, no ads, no nonsense. Thank you!

[@rodenreyes6320]

Somebody famous in YT making things and tests accompanied by schoolgirly, bubbly giggles and laughs in his well-appointed shop...he once hosted a tv show.

[@Willpolita]

I miss this very much, nowadays if a video has 10min, 4 are of futility.

[@AlTheEngineer]

@@Willpolita sand. Good ol days are gone I guess.

[@DesideriusTheSerious]

And yet this is one of the videos "like the good ol' days". Just sort out what you're watching so the algorhitm doesn't suggest you rubbish. It's all on you.

[@AlTheEngineer]

@@DesideriusTheSerious no matter what I do the algo suggests shorts and garbage most of the time.... Sadly.

[@j.frankparnell6195]

I have cooled my entire house in the summer like this for years. Pick a window on the upper floor, or at the farthest point from your bedroom. Open all of the windows in the house. Wait until the temperature outside drops below the interior temperature and then turn on that fan and blow the air out of the house through a single window. This will take in cool air from the outside. Then in the morning as the temperatures rise, close all of the windows again. You will be amazed at how much cooling effect you will have without resorting to air conditioning.

[@georgehill3087]

Basically a whole house fan. Problem is humidity from the outside, unless you are in a really dry place.

[@DistracticusPrime]

I have relied on this technique all summer long for several years now. Northwest United States here, so the weather often gets up to 95° but cools off at night. By managing the windows and fans as you described, we don't even need air conditioning. (Bought one anyway, just in case of wildfire smoke.) It's especially effective in a tall building, like a two- or three- story house. Once the windows are closed and the air gets still, warm air floats up to the top while the lowest floor is much cooler.

[@dardanpaloka4413]

yea what about the humidity

[@DistracticusPrime]

@@dardanpaloka4413 Usually around 40-60% here in the Pacific NorthWest (which is weird, considering our reputation for eternal rain.) That's a critical factor I meant to volunteer in my post. In a humid climate, you just need something with a condenser. Acclimation, shade and humidity matter more to me than the thermometer reading.

[@j.frankparnell6195]

@@dardanpaloka4413 It's not a problem out here in the West.

[@heatherwade2373]

Fan placement really does make a difference. I live in the desert and it’s very hot here during summer. My ac is in a bad location in the house so I have to use fans to pull the cool air throughout the house. I have spent days and days moving fans around to find the perfect configuration for maximum cooling. One fan out of place and it will get hot, in the right place, I can stay 75 on a 100 degree day. There are a lot of factors and every home is different. Experiment with your fans! Move them all over the place, you will find the best spot. In the right location a fan on low can really help keep you cool.

[@RG-bk2dd]

I do the same experiment the problem is that I have a ceiling fan and it cannot be moved, so to have the better freshness I'm the person who has to move 😅

[@EngerJimenez]

100 degree Fahrenheit or Celsius?

[@fade2008]

@@EngerJimenez are you considering boiling yourself? no, not celcius, hopefully

[@KilleRoy_NL]

​@@EngerJimenez I kinda doubt you'd survive being in 100 Celsius so assuming Fahrenheit

[@CRegaladoDA]

@@KilleRoy_NL I doubt you would even survive anything above 45 c°

[@AmazingChinaToday]

This is an AWESOME experiment!

[@tanmay_6363]

😥

[@anunnakinibiru]

Best of the experiment was 4:57

[@anunnakinibiru]

@@repentandbelieveinjesuschr9495 Matthew 4:10 "Away from me, Satan!" Jesus declared. "For it is written: 'Worship the Lord your God and serve Him only.'"

[@earnmoneyonline2756]

My name🙂

[@mompfreed.]

Thats definitely in the category of „thats exactly what I wanted to see and I didn’t know I needed it in the first place“ Thank you Algorithm and thank you Matthias!

[@creativecanon]

Finally a to the point test with clear testing and results without 5 ad breaks and sponsor shoutouts for testing the best plastic bag to paint your doors with. Thank you.

[@dimitrijekrstic7567]

Yeah, actual testing being done and results shown. Refreshing

[@AFAndersen]

Would be great if your sentence had an ad break...

[@Paradroidx]

That's because KZbin, not the uploaders

[@h.celine9303]

I'm now really curious about the bag. How could I possibly paint my doors with it?

[@willw.1466]

Just coming back to say that this has made our lives better already. We've been using fans all wrong and this makes a massive difference. We can now be comfortable in our apartment on hot days and it feels amazing. Thank you, thank you, thank you.

[@endor8witch]

I use fans to blow wind at me lol

[@Emsyaz]

@@endor8witch its logical 😂

[@BC_Geoff]

@@endor8witch you can do both at the same time! Cool your house and yourself. Just need a few fans.

[@etherealrose2139]

Then be amazed if you made a simple cowl for it...

[@GicaEric]

Hi sir. I want to thank you from the bottom of my heart! This tip solved a big issue for me and my family. We hated summer times because we had trouble sleeping in our apartment. I have a quite powerful AC which does the job, however it was drying the air too much and my little daughter was having trouble with her throat. We got quite a qood humidifier but it didn't do much. ... but man, this tip, I tried in and it made the temperatures ideal for sleeping without sweating. It's been 10 days since I implemented it and in all of them we slept without any issues! Thank you a million times and God bless you good sir!

[@Silv3rDragon]

Goes to show you may never know how much of an impact a simple curiosity experiment may have on someone else's life. Thanks for sharing.

[@agentsixtynine]

This comment ❤

[@maximusbzg]

Thanks for sharing

[@piggnant]

summer nights no need to turn on the AC anymore? : )

[@zandacross2983]

@@piggnant 😐

[@thestudentofficial5483]

This is the Bernoulli effect! Basically, why the windblown section is not a cylindrical column extending from the face of the fan, but rather an expanding cone, is because moving fluids (in this case, air) have lower pressure and thus "pull" nearby fluid particles to move along. So originally, the windblown section would of course be a cylinder, but at the edge of that cylinder, moving air particles pull along stationary particles, and then the now-moving particles also pull another stationary particle and so on until the kinetic energy dissipates. This is also why you must stand behind the line at train platforms because the moving surface of the train will "pull" your body into it.

[@weaboo101]

Funny, we're currently having refresher in Bernoulli's principle. And I remember losing my mind on that lesson lmao

[@mollyrosefrancis]

Is this also why a running shower will "pull" the shower curtain into the tub??

[@bgotura]

Coanda effect also important here I guess?

[@factland28]

Remind me of Pre-2014 Old School KZbin, No flashy Shorts, No Over Commercialisation , no extra spicy editing. Just Pure Knowledge and experiments ❤️

[@Kiwi-Ahh-Nah]

And the icing on the cake...no clickbait thumbnail featuring a silly reaction expression!

[@HiItsMars]

“Pre 2014 old school” Lol old school for KZbin is literally almost ten years before 2014 my man

[@MiniKodjo]

no vpn sponsor, no money begging, no social metworks

[@umershaikh7179]

@@HiItsMars lol yeah, real old school is pre 2010, that’s when KZbin was completely different

[@zedsdeadbaby]

there's loads of videos like this that are straight to the point, you only get 'commercialized' videos with 'spicy editing' because youtube looks at your watch history and gives you videos based on that. so if you don't want those kinds of videos stop viewing them.

[@SodaQuasar]

This is like overclocking home edition

[@vxllvxn]

😂

[@thisaccountisntreal107]

I'm kind of into this tho I might oc my home's air conditioning

[@4ae109]

more like undervolting! it seems counterintuitive, but does help performance.

[@Ignisan_66]

Do you even know what overclocking is?

[@Corvus-it3dj]

​@@Ignisan_66tedious adjustments for little increased performance Exactly what is happening in the video

[@dommy114]

Racheal: "Do we really have to keep this fan in the middle of the room?" Matthias: "IT'S OPTIMAL! And it's NOT in the middle of the room. It's precisely 52.068cm from the window!"

[@antraxxslingshots]

@Ken Mason She will return when she realizes how hot that place is compared to his :D

[@xxportalxx.]

Sounds like a big bang theory skit XD

[@abhishektiwari7127]

🤣🤣🤣

[@SE45CX]

I'd say 520.68 mm.

[@TANMAN9095]

@@antraxxslingshots No, because they have a working air conditioner.

[@chandlerstewart7941]

My girlfriend would tease me about starting an 'Airflow' channel, as I nerded out into seeing how long we could go into summer without air con - you did it my brother! I currently use 2 box fans - one pushing in, the other out, right up against the window, BUT I close the window up to the fan so opening is about the size of the box fan. Moves air decently. Ceiling fans on low to evacuate hottest air. I used incense smoke to find window leaks - don't have a meter or graphing capabilities - nicely done!

[@LJ-ft1ic]

You struck on the KEY when you said "BUT I close the window up to the fan so opening is about the size of the box fan". When you put a box fan in a window, you must seal up the rest of the opening (with cardboard & tape, or a piece of plywood) if you expect any air movement. But when you do, it is very effective of creating air circulation. I've used 20" box fans installed in windows for cooling, air circulation, and even exhausting airborne contaminants during home improvements, for over 50 years. (And saying that makes me feel old...) 🤔

[@arsnakehert]

Really gotta appreciate people who go out of their way to make good content like this

[@kroongj1]

Matthias gives the answers everybody wants to know on the questions nobody asked.

[@brothyr]

thats what an engineer does.

[@coalitionofrob436]

I have asked this on occasion, Australia is a hot place

[@MandoFettOG]

Until 7 years from now when a celebrity posts on Twitter about putting a fan in the window..then it will end up with 20 million views in 3 days.

[@JBrothersz]

I ask it myself whenever it's hot inside 😜

[@NomNomNom1989]

Today I was trying different positions for my fan as well because the air circulation in my room is horrible. Thats why Im very surprised that this gets suggested to me.

[@Gokudo87]

RIP boxed fan. You dedicated your life to science and your research will change the life for generations to come.

[@optimistprime2751]

I propose we commemorate the box fan with a statue for it's contribution to science

[@rickporayko880]

Very respectful, guys!

[@lc7ineo]

This channel is one of the few reasons KZbin is still worth while.

[@NoggleBaum]

My father, an civil engineer, was doing this experiments back in the 60's at our house. It was a big house. Finally he sealed/placed the fan in a stair way window and kept the inside doors in a closed circuit, porch to kitchen, to living room, hall way and ending in master bedroom. We never had to run the AC until June then only in the afternoons. (Atlanta GA area).

[@eggbenedict-gt7mw]

😂😂😂😂 no need to be an engineer, i have done better

[@sleepyearth]

@@eggbenedict-gt7mw No you don't 😂😂😂😂

[@JeronimoStilton14]

@@eggbenedict-gt7mw First of all he said his dad was a civil engineer, not that it was required, but that distinction probably went over your head. You're so desperate for attention you replied a comment without data, and said you did better, despite it being impossible to prove that.

[@tarabooartarmy3654]

My granny also lived near Atlanta. She always put a box fan in the front door. In the daytime, she would have it blowing outward to push hot air out. In the evening, she would turn it around to pull cool air in. She never had an air conditioner and it was always relatively nice inside her house except on the hottest days of summer. It helped that she had two massive oak trees shading her house.

[@lijkn]

He could have been a good youtuber and shared the results if there had been youtube in the 60's!

[@insevanhouts]

Dude, this is like one of the best expriments I've ever watched on KZbin. No nonsense, clear data, love it!

[@gregfeneis609]

Nice work, Matthias. Patton, a fan manufacturer, recommends this in the literature that came with a fan I bought several years ago. As you have found from experimentation, best air exhaust from the house is blowing out from a distance from the window. Their illustration appeared to suggest a column of air being blown from the fan out the window central to the window opening, and other air current being invited to join the column going out the window. A turbulent column inviting some surrounding laminar flow ambient air out with it, if you will. A larger net effect VS placing the fan right at the window opening and only getting the column of air exiting the window. I have found that effectiveness of this strategy varies somewhat by fan setting. If I don't want as much air flow through my place, I turn the fan to a lower speed, and air flow goes way down. Then I move the fan closer to the window and air flow recovers a bit. An interesting variation on your experiments might be to establish a baseline air flow with the fan right at the window at max fan speed, then see how much you can reduce the fan speed with optimized distance from the window, to achieve the same baseline flow rate.

[@lynguy8824]

Thank you

[@ghz24]

Entrainment.

[@anshulgupta9754]

This is pure KZbin experiments. Exciting, motivating, sweet and simple.

[@DirtyDishes2222]

I was trying to figure out what's the best placement for fans just by using logic, but quickly realised it's a pretty tricky question and probably needs actuall testing. This video is highly apreciated!

[@shashankdegloorkar]

and im impressed by those big digit console output.

[@mikesherrill8695]

Now here's a man who has never uttered the words "I'm bored"

[@recklessroges]

A rather harsh motivation that was thrown at me during my childhood: "Only fools are bored."

[@kinstar]

This guy is the type of person who really makes you question all the time wasted by doing nothing but saying you're too busy xD

[@dinkerz]

I’d argue he says I’m bored all the time. Otherwise, why would he start to ponder optimal fan positioning and the need for actual science confirmation if he were already sufficiently stimulated.

[@CarlosReghis]

04:58 Only funny part is.. oh great experiment over.🤣😂🤣😂😅

[@jerkycam]

I think there's two types of boredom: 1. "I'm bored nothing satisfies me" 2. "I'm bored, time to find some thing to do." The second one only lasts a moment.

[@fd0198]

we use the same principle in the fire service. when we use a fan to clear smoke out of a house we point the fan at the front door and make sure the cone of air covers the entire door. we open all the windows and close the doors except for one. when a room is clear we shut the door and open the next room. you can clear out a house in a matter of minutes. 😊

[@lint2023]

Years ago in a non-A/C house in MN I made a plenum that I could hang in the top sash area of a window and the box fan would set horizontal on the thin wooden plenum about a foot from the ceiling. That exhausted and pulled the hottest air from the ceiling and pushed it outside. Worked wonderfully. Better than any other implementation I tried.

[@matthiasrandomstuff2221]

cool. I'm sure that got lots of questions from visotors!

[@lint2023]

@@matthiasrandomstuff2221 It actually looked nice. I made it look nice. Triangular cross section if looking from the side and guiding the air towards the window. This allowed me to walk by the window without hitting my head. Remembering now, it only fed and fit the top half of the top sash. Not that noticeable from the back yard. :

[@oscargr_]

That's pretty clever.

[@lint2023]

@@oscargr_ Thanks. It worked so well I used it for years. I could close the top sash without removing anything and it fit in place without any fasteners. I showed it to the people that bought that house from me and they chose to keep it.

[@stallion63m35]

That's the right way to ventilate. Hot air rises.Vent out the warm air near the ceiling so that cooler air can come in to replace the exhausted warm air. For the best result you need cross room ventilation.

[@ReyLaFleur]

dude its summer and you just made my bedroom noticeably cooler

[@Grandpaneedsblood]

Buy an ac

[@WhiteCranK]

@@Grandpaneedsblood there are a few downsides with using an ac

[@Blernster]

@@WhiteCranK wat r they then genious

[@WhiteCranK]

@@Blernster wasting electricity, the cooled air isn't healthy and make headache and/or throath diseases, they're loud and need a lot of space... "genious"

[@falls2180]

@@Blernster climate change

[@StrokaReviews]

The fact that he took time out of his day to do a detailed video of something we needed is beyond great.

[@RichardFStripeRendezvous]

Two days actually!

[@freemansame8062]

Humble, fair, polite, honest and I can go on until tomorrow, the world needs more people like that to make it a little more pleasant to live on earth. Thank you !

[@dhruva08]

I cant bloody sleep due to humidity for weeks, middle of night im wondering wtf to do, moving around the bed and furniture with this new science i learned, thankyou

[@adityan3208]

Yo just get a dehumidifier

[@AngelSnowflakes]

@@adityan3208 expensive

[@Peachu_n_Goma_Home]

Close yr windows use a dehumidifier

[@rodelscreation]

At first i did not believe this but gosh I couldn't believe when i started to feel the air circulation inside my room, thank you very much for your wonderful video, sending hugs and kisses from Philippines

[@mr_coffee0508]

tropical country :(

[@rodelscreation]

@@mr_coffee0508 yes I live in Philippines, sadly I can't afford to buy aircon, so thid method really made a huge difference compared to not doing this technique

[@yammyong]

came across this video today - fixed my poor ventilation for the last 1.5 years. even the box fan test helped me understand the difference in efficiency of design. thank you!!!

[@Dial8Transmition]

I think this will save me from another blazing hot summer. Always had a fan in my room but have been using it the wrong way all this time. I place it so that it blows the air out my window instead, and in the evenings when it's cold outside I turn it around to pull cold air in so my room is cool at night, it works so well. Thanks

[@jacobruddiman9271]

As many people have said, it seems to be a result of the flow of air pulling more adjacent air out the window along with it. I think this is the bernoulli's effect, which you can look up someone blowing up a large bag with air in one breath because of the same principle.

[@KuZeTrApT]

Exactly, that's correct.

[@BrownCookieBoy]

I believe its air entrainment.

[@stuntpenguin]

you get some nice entrainment, and you also manage to stop most of the air from coming back in through the same window again

[@RealBoiJare]

Yup, I remember my science teacher showing me that effect in grade 9

[@Ryuuuuuk]

This is related to Bernoullis principle. Locally increasing the air speed decreases the pressure, leading to surrounding air streaming into the low pressure region. If you place the fan directly in front of the window the same happens, but the surrounding air will be on the outside, rendering the fan useless.

[@jonathanlin1000]

My favorite thing about this video is that each time I started thinking "but what about..." you jump in to adjust and account for it, throwing in a concise explanation as a bonus. So good!

[@hereandthere4751]

what if the anemometer is backwards thats ehy it didn't spin for (fan facing inwards)? unless does the device works on both directions??

[@unliving_ball_of_gas]

@@hereandthere4751 I think it does work in both directions, since wind speed is a vector, it's just that it would spin backwards and maybe show up a negative reading

[@defectivepikachu4582]

@@hereandthere4751 fan facing inwards does nothing for circulation cuz it can only suck in air that is right behind it and the wind it generates is immediately lost

[@dakotamartin1621]

We use this in the USA to ventilate houses in firefighting. Back the fan off the opening just enough to where the cone of moving air from the fan cobers the opening. You can take another fan, put it outside on the other side of the house and have it force air into the house. Again you want to back it away from the opening far enough for the cone of forced air to encompass the entire opening. Also, all other windows and outside doors have to be closed for it to work.

[@whoisisaac]

Are you trying to burn the house down faster?

[@dakotamartin1621]

Did you think that sounded smart? It is obviously used to ventilate smoke AFTER the fire. I don't know if you were trying to sound funny with your comment or not, but instead you showed a clear lack of practical sense, and an aptitude for stupidity. There are other methods of ventilation used in active fire situations btw, but I don't think you would care to know by your comment.

[@CHAPI929292]

@@dakotamartin1621 i think it was a joke lol

[@Wenjo936]

@@whoisisaac im sitting here like "isnt he describing those backdraft rooms?" i thought dakota was trolling til the end

[@o0Avalon0o]

Thanks for explaining it so well. Fellow firefighter here, can confirm this is how we ventilate a building. There's a lot of research on this so we see it as part of our training, and it is very interesting to see it work for yourself.

[@redheadedhermit8693]

this is the type of videos for which i open KZbin made me feel like a curious child watching cool science stuff after returning from school

[@barrybortnick7999]

I love the fan research, we need more citizen science! Measuring air flow is one variable, but another important metric would be the change in temperature with different fan orientations.

[@weixianng]

This! Temperature and humidity is what matters I suppose to the occupants!

[@BC_Geoff]

There would be too many variables for anyone to apply the data to their own situation. This video is good because he measured a simple metric that anyone can understand and means something no matter what your situation is. The more air you move the better. For temperature It all depends on how hot it is outside and how hot it is inside and how many windows you have available and so on.

[@racingdesire]

from experience if the outside temp is cooler than inside, if your using a fan the fastest way to cool the inside air is to blow outside cooler air in. blowing air out is very inificient in the same conditions for cooling.

[@jamesvelvet3612]

My guess is there is a causal correlation between amount of air you can exchange and the delta between the two temps you are comparing (inside/outside air). Could probably work something out knowing those numbers. My guess is more air exchanged, the quicker the delta's converge.

[@Simoxs7]

This actually makes sense to me, In Firefighter training here in Germany we get told to put up a fan at a distance where the cone of wind coming of the fan covers all of the Door / window. (We use large fans to air out homes full of smoke)

[@buttercatz99]

Firemen slowly become phsycopaths. In the top 5 people to not get married to.

[@maximeteppe7627]

I'm guessing the initial air flow drags additional air surrounding it,producing a larger flow at a distance, (I can't remember the name of the effect.. It's not venturi, but one of those. anyway, if the fan is at the edge of window, only the air straight through the fan is evacuated, while the air dragged along is outside air. If the fan is further away, it drags a larger amount of inside air and pushes it outside.

[@Julzaa]

That would be the most logical

[@johannes.f.r.]

​@@maximeteppe7627Yep. Bernoulli is the name you were looking for.

[@Bialy_1]

@@maximeteppe7627 It is "The Venturi effect" and he made video about it 9 years before he made this video... kzbin.info/www/bejne/hJKcgIWejs-pgLcsi=kdDp1AZNLgxYqog4

[@skippylippy547]

I installed a large fan in the apex of our attic. Not only does it remove the hot air in the attic, it pulls the cool evening air into the house and cools every room down considerably. Attic fans work! 👍

[@nefariousyawn]

I used to live in a house with a big extraction fan pointing into the attic. It was noisy but the breeze through the house felt great. Is your attic fan purpose built for being in an attic? Did you have to add any ducting or vents?

[@bobd.]

I put a solar power attic fan in my roof over the shop. Before the fan I monitored the temperature in the attic space with an indoor/outdoor thermometer. I kept the indoor unit in the shop and the outdoor unit I stuck in the attic. The temperature exceed 140F any day the ambient temp was over 85F. This made the ceiling of the shop which is insulated hot. After installing the fan the hottest is has been in the attic is 126F, so about 20 degrees cooler. I have noticed that the temperature in the shop stays about 5 degrees cooler than before the attic fan was installed. Solar powered so only works when the Sun is out but hey that's when it's hottest so it all works out.

[@skippylippy547]

@@nefariousyawn Yes the attic fan was purpose built for being in the attic. (30 inch diameter 4 blades) It came with a round cowling that installs in the apex. I removed the extant square vent that was built with the house and created a round hole that fit the cowling. I sealed everything and then mounted the fan. (the outside of the cowling has louvered vents that close when the fan isn't on.) I installed a wall mounted switch for the fan in the hallway underneath so that we can manually control the fan. It also has a thermostat that can automatically control the fan when attic temperatures exceed a set point. The fan is quiet and it has an oil port for lubrication which I oil every spring.

[@skippylippy547]

@@bobd. Sounds like you have a good solution for your shop! 👍

[@stephenhegarty]

@@skippylippy547 I’m just researching options in Canada ... what brand did you install?

[@tiario22]

Great video!! I learned as a child when sleeping in my grandparents attic bedroom to pull air in one window with a fan and blow it out of the window on the opposite side of the room with a fan. I'm now 63 living in Florida and still the use this method often to move air through the house.

[@homer46303]

Not going to lie this is one of those things that, to most people, might seem benign but it's really interesting. This is why ducting on fans is so helpful. Subbed.

[@jessicaallen4613]

Placements + size + fanpower+ shape of room +

[@rob9781]

This methodology is what we need to be teaching in schools.

[@ateryx]

You mean the scientific method? The one that is taught in schools?

[@pinefilms3141]

@@ateryx the idea of the scientific method is covered, but it's application in the real world is rarely talked about. we're just all suppose to "trust the experts" and if we use the internet in any way to get our information, it's faulty and "unofficial"

[@ateryx]

@@pinefilms3141 Maybe you slept in science class? It is definitely talked about and used in schools. Remember, research is only the FIRST STEP in the scientific method.

[@HunterKiotori]

@@ateryx the scientific method has fallen out of favor. Now you believe the science, or you're a science denier.

[@madisonbrown8851]

@@ateryx I think you need to work on your reading comprehension, kiddo.

[@Bibblebibble480]

Omg this is actually so helpful, Iive in a tiny VERY stuffy house and the placement of it around other houses makes it so hard to ventilate

[@crixi__]

I love how you were really scientific about a thing that other people would put off as unimportant. I loved it, learned a lot. Keep it going! Thanks

[@sadlemonissad1401]

Believe it or not, I've discovered this about 2 years ago by accident, I was cleaning my room, and my intention was to pull the dust outside by putting my fan facing my opened door and about in the middle of the room. While cleaning I noticed that my room was getting cooler and cooler over time.

[@TheAbandonedAccount7]

So, how old were you then when you discovered airflow?

[@sadlemonissad1401]

@@TheAbandonedAccount7 37

[@Verdeniza]

@@TheAbandonedAccount7 that question made me laugh 🤣

[@sadlemonissad1401]

@@Verdeniza ikr 😂

[@jeb123]

But this has nothing to do with how far the fan placed from the window

[@TheMalibuDar]

This is what early KZbin was made for. Simple. Not overly produced. Great info. Verifiable. Well done!

[@bestieswithtesties]

This is what early KZbin was made for. Stealing year old comments and slightly rephrasing them before reposting to thirst for internet points.

[@GOAT_GOATERSON]

​@@bestieswithtestiesI was thinking the exact same thing

[@_InTheBin]

it's hot, it's humid, it's past 2.30a.m. and I'm rewinding this clip which I saw some time ago accidently and which now is more than helpful. Cheers mate!

[@miguelagawin]

Trust anyone with a raspberry pie laying around for experiments.

[@thecapacitor1395]

I always pointed the fan out the window to help air flow, not sure why done this, it just made more sense to me that way. Now I have the data to prove it! :D

[@SmallSpoonBrigade]

Pointing a fan inward makes the fan increase the air pressure to get hot air out, pointing it out doesn't change the pressure outside to any appreciable degree.

[@WillJackDo]

That's insane! It feels so counter-intuitive, yet makes so much sense. Thanks for making this video.

[@solonsouzafilho]

So good to see a true oldschool youtube science video. Subscribed.

[@MrMarksman36]

Summary for those interested in the experiment result data and conclusion: Circle fan: 3:41 Box fan: 4:44 The conclusion: 5:43

[@Reibaku]

It’s to that long of a video, people should just watch it.

[@coltynstone-lamontagne]

​@Reibaku this is more for when you come back to it later and want to check specific parts

[@jasonblaha6891]

Ty

[@MrMjolnir69]

Thank you!!!!

[@QuillC]

Had to comment again to express thanks, I've now shared this with numerous people who don't have A/C during the current round of heatwaves, so thanks so much for helping keep so many people cool!

[@Akuroxradio]

Hi Matthias ! Last summer (July 2022) I did the same kind of experiment! And find about the same results. My fan was one of those tall 5' on a pedestal 18 inches blade. The best distance was about a meter and a half from the window. Since air acts like a liquid, one has to think outside the box. ( or outside the fan cage in this case) From what I gathered is that those fans dont pull air much from the back but they actually create a turbulence around the cage that pushes the flow instead of a coherent vortex. (like a turbine) I am happy to see that someone actually did a better scientific approach!

[@CalvinHikes]

I'm trying to find one where the results include blocking the window off where the fan is. Blocking the edges so there's no leading back draft. Whenever I put a window in a fan I always block the unused portions of the screen off.

[@wolfiemuse]

@@CalvinHikesI imagine that does improve air flow, but not by a significant amount. Probably the difference between .6 and .7 ish

[@KasumiRINA]

My floor fan rotates so I put it in the corner of the room so it's not always pointing straight at me.

[@ultimatecake2231]

The turbine analogy helped me understand better, ty

[@halogenlampert]

Hello there! I watched this video and followed the conclusions you came to and I think I can feel a gentle breeze of cold night's air blowing through my non-airconditioned apartment and I want to thank you for that!

[@OmegaphysX]

Well done, rare to watch such to the point no nonsense content nowadays. Real smart people have no time to fool around. I used to do this in a non a/c room. I selected the optimal fan placement distance by observing how high the curtains on other windows get blown in by the low pressure the fan generated. This way I managed to keep the room about 8 degrees colder compared to the 32degree Celsius outside air.

[@BarneyGumbl3]

*He actually did it* What a legend, doing the experiments we all want

[@Sierra-Whisky]

A few years ago I built a fan with a tight enclosure to fit in a window, effectively sealing the window off. With only a few mm between the fanblades and the enclosure, it draws quite an airflow.

[@head85]

Definitely not an ordinary fan!👍🏽

[@EvenTheDogAgrees]

@@head85 PC cooler fan or similar, most likely. Those are the easiest to mount onto a wooden window insert, as they come with screw holes. You can even get larger models, e.g. 200mm instead of the most common 120mm, meaning you can spin them slower (reducing the noise) while moving more air.

[@Sierra-Whisky]

@@EvenTheDogAgrees my fan (and it's "enclosure" (not sure how to translate it in English)) is built into a wooden insert, just as you described. The only difference is the fan itself. It's an industrial grade 230V fan of about 500mm (no typo) and draws well over 3000m³/h. 🤣 When it was still in use, I usually ran it at about 40% capacity to avoid complaints from my neighbours across the street 🤣 Trust me, I've been laughing my ass of after I turned it on for the first time. Up until then I just didn't have a single clue what it would be like to have a fan blowing 3000m³/h of air through my apartment 🤣🤣🤣

[@EvenTheDogAgrees]

@@Sierra-Whisky LOL, that's epic! Thanks for the laugh! 😂

[@cimachu]

I live in my room with my dog, and I do this to air out his smell. This was very useful information and I immediately noticed a difference when I moved the fan a few feet from the window. Thanks!

[@Dan-gs3kg]

The thing happening here is air multiplication, vector augmentation, or entrainment. It is used for very high volume pumps, like bilge pumps and the air pumps that instantly fill the emergency slide for planes.

[@wownoyoudont861]

Thank you I scrolled down to find this!

[@drblitzkreig]

Yes, based in Bernoulli theorem....just like a venturimeter

[@Dragonfall-lu6qe]

Thank you for this. I have 1 pedestal fan and a floor fan and have been experimenting on how to get the greatest air flow in my house. Simply moving the pedestal fan 2.5 feet from the window and using it to vent has given me the best cross breeze I could ask for

[@yasha1928]

I've always been curious about this and constantly try different placements throughout my house! Love your videos Matthias!

[@Franku40keks]

Weather is getting hotter, the algorithm blessed me with this gem the best time possible 🙏

[@Honeneko.]

Neat. I've played around with this as well. I use a Lasko-Premium-20-in-3-Speed-Box-Fan-3723 from Home Depot. I place it on a window with nearly the exact dimensions and a bit of foam padding where it has the smallest space. Works great pulling and pushing air through out the house. This fan is very noticeably stronger than other box fans I have around. It's also very, very noisy. I've seen even stronger fans but for more than double the price. And probably even more noise. I've tried placing it in larger windows with noticeable levels of lower airflow. I think the reason why the fan is pulling/pushing air in the opposite direction the fan is blowing is because of space around the outside of the fan. Maybe you'd get better flow in either direction if treated more like an Air Conditioning unit where the window is sealed around the fan.

[@jeffparcel]

Your work in home physics is unparalleled.

[@jessicaallen4613]

I also played with fans wen I was a kid; ' 'i am a robot'... Spoken through the beautiful big boxfan! ☺️

[@TehCheezMan]

Great video! Everyone who is saying Bernoulis principle, there's more! It's called static air pressure. A small fan directly against a window just thrashes the air and shoots it forward, but doesn't establish an air pressure difference between the INSIDE and the OUTSIDE of the window. Air can just flow around the sides of the fan. We see this with decreased air flow/speed readings in the video. When you move the fan back however, the air flow "cone" spreads out and you create an even blanket of high air pressure across the ENTIRE window. Its the same effect if you were to use the square fan in the window and add cardboard to the top to fill in the rest of the window gap - air is then forced in a single direction through the window instead of freely flowing around a fan in the same window.

[@Crushonius]

what you just described in laymens terms is exactly what bernoullis principle is talking about its all fluid dynamics and in physics air is considered a fluid you should really read up on it and you will understand that the people saying bernoullis principle are 100 percent in the right

[@TehCheezMan]

@@Crushonius Bernoulis' principle is more relevant to airflow in a tightly constrained system no? It's also the way a Dyson fan uses a ring of fast moving air on bladeless fans. I think this example is more simple than that....just an opinion. I might be mis understanding, where the fan cone is smaller than the window opening, and there is some venturi effect happing across that pressure difference (in/out of the window) 5mph wind on the side of a house VS a 100mph leafblower directly in a window will yield similar results to the OPs test, but a leafblower in a tube could draw a vacuum to move more air (venturi effect) than it would on its own. My thought was air flow through the house is not laminar enough to take advantage of this.

[@xXSaberToothSamuraiXx]

i dont care what anyone says, this is an invaluable and unique video, thank you so much

[@listen2thedude]

Dude, 100% respect. This is a life changer for many people paying attention.

[@Carnac311]

This will be really helpful when I move back to Europe next year. Normally no AC, so to keep your house somewhat cool during heatwaves you kind of develop a strategy/timing of when to open and close windows, shades, etc.

[@hunakosdem]

Playing this exact game right now :)

[@iair-conditiontheoutsideai3076]

They make this wonderful invention called a portable air conditioner it was designed for houses that do not have central air conditioning

[@radekoncar2404]

@@iair-conditiontheoutsideai3076 They are inefficient and have variable loudness when compressor is turning on and off. That's why I finally moved the whole thing outside and I'm sucking air from the room through a hole, moving it through the evaporator and back into the room through another hole. Well-insulated hoses, silent compressor, better efficiency.

[@iair-conditiontheoutsideai3076]

@@radekoncar2404 yeah if you want to go that far with it considering most these people don't even have air conditioning I think something would be a start for them

[@807D14M0ND5]

@@radekoncar2404 Did you move a portable unit outside? If so..I'm listening!

[@magenblevins2957]

I’ve been waiting my whole life to hear this! After putting box fans in my windows and blowing air inside, I am now changing my ways! Thank you so much for your thorough experiment & data! :)

[@roidroid]

He never tested a box fan blowing air inside tho. I guess the fan broke b4 he could.

[@HotJuicyMess]

i use the box fan on my window hanged from the top with a strap, then I have a towel covering the bottom and the window slightly closed (my window is big and opens horizontal) It sucks in air so good and it kinda creates a wierd pressure in the room but it feels so good. when you stand outside my room with the door close, you can feel air rushing out from the doors. 100% reccommend atleast trying it.

[@CrocodileWhispers]

I can air out my stinky roommates room so much easier when he leaves for work!

[@anon7661]

​@@CrocodileWhispersprobably better spent time looking for a job for yourself

[@CrocodileWhispers]

@@anon7661 we worked shifts opposite ends of week

[@mtrps_]

i remember watching this a couple years back, and it still helps me to this day 🙏🙏🙏

[@mdoering]

Thank you for confirming my theory on the best way to use a fan with windows. I live in a multi-story house, and I also use convection to provide a bump by placing the fan in the highest open window and opening the lowest windows for air to be pulled in. I'm fortunate that the lowest windows also happen to be north facing, and adjacent to a large shaded concrete pad, so I assume there is some added cooling gained there as well by pulling the air across a large mass/surface area that is cooler than the ambient air temperature in the sun.

[@jonmike316]

so open the lowest north facing window, then open the highest south facing window then put the fan facing the south window?

[@charcoalisblack1488]

No joke, this guy proofed that I've done the right measurement for my room! I'm living in a very small room usually closing the door with only fan and not air-cond, the room temperature was really hot when the weather is hot and I tried to turn my fan towards living room with door opened, and it result in getting more cold air in my room instead! Thank you for doing this air circulating science stuff! I was so excited when I found that someone actually do this to collect data!

[@febrianr8578]

I wonder what is the distance between your living room towards your room?

[@jtknight4647]

Nice analysis! I'm an airflow expert and run a WHF company. The best way to get max volume and velocity is to pull the air IN through windows via WHF installed centrally and at highest point in house. With a 2-1 ratio house sqr ft to CFM you will get 12-15 air exchanges per hour. Besides cooling effectively and saving money vs AC, it eliminates odors, viruses and contaminants of all kinds. For me the study that i need to to confirm, although i know what the results will be, is the amount of window opening to maximize the venturii effect at each window(max velocity). Less is more, but there is a sweet spot for each scenario/layout. I tell clients to play with it until they notice he max boost

[@nomnombr]

What is whf?

[@jtknight4647]

@@nomnombr Whole House Fan

[@Lili-xq9sn]

Yes. I had a difficult apt where no room opened to the next room. One level/top floor and hot. I had 3 whole house window fans and played with how much and which other windows to open in this scenario -- because the fans in different rooms couldn't communicate with each other. I found that cracking the top of window #1 in a line of 3 window with the WH window fan in the bottom portion of window 1 worked best.

[@Nessal83]

Are you sure it reduces bacteria? We've done lab work on agar dishes exposed to outside air versus inside air and the bacteria growth was easily 10x more after 7 days of incubation for the outside air.

[@jtknight4647]

@@Nessal83 yea I’m pretty sure as are the WHF manufacturers and I think the EPA. Still that would be a good field test: test agar samples INDOORS with OUTSIDE air being drawn in over a number of hours/days

[@eifet]

Leaving a like and a comment for the broken fan. You’ve made some sacrifices for science, I feel that you deserve some appreciation!

[@cosmicallyderived]

This is brilliant, getting empirical, getting numeric, we need this objective non nonsense curiosity. Keep up the good work!

[@Studio23Media]

This effect can be demonstrated fairly well by using a fog machine to visualize the airflow.

[@Pauluz_The_Web_Gnome]

Or use a whistle-blower!

[@usbgamers123]

Or by setting your house on fire. If the flames are getting bigger it means the air flow is good

[@user-exuytv]

@@usbgamers123 about to set my house on fire to test the air flow, thanks for the tip! 🙏

[@ferchemac180]

@@usbgamers123 you are a genius

[@thecoldglassofwatershow]

Or smoke some weed instead 😄

[@bobman929]

This is science. Recorded results, acknowledged and accounted for limitations, tried multiple scenarios, gave recomemdations and said why something don't work and confined his talk solely to what he did and not what anyone else did or said.

[@mcfireballs3491]

Except the part where multiple unassociated testers do exactly the same to check the validity of the results...thats the single most important feature of scientific research...and you forgot to mention it -_-

[@विचित्रलड़का]

​@@mcfireballs3491lol

[@blackmounthare]

Thank you, my dude! I live on the basement floor of a German house, so we do not have any air conditioning The air gets really bad in the basement, that's why I have to put a big fan in the room while I'm at work Most of the time there's a lack of oxygen down there So this helps a lot!

[@Asemco]

I never forgot my Grade 7 teacher teaching this to us, however he didn't go into detail about the distance away from the window. Thanks for filling in that gap! Also avoiding box fans. I want the all in one

[@franciscoosuna259]

Thank you Matthias, this was VERY interesting. Years ago I found myself trying to maximize fan efficiency, but in an emergency situation. My wife decided to help me by hard boiling some eggs for my lunch while I went out to the store to buy a couple of essentials. I returned to find our 2 bedroom apartment filled with grey smoke from the 12 foot ceiling to 3 feet above the floor. My wife had fallen asleep. (As an aside, you might consider an episode on what household items produce the best smoke. Eggs might be a good choice because they did not ignite like bacon would.) The data collection was not very accurate but more eyeball observation. After several fan positions, I determined the quickest way to clear the smoke was to remove the screen from the terrace door. It is obvious after thinking back on my FLUID DYNAMICS class. Although the filaments of a screen occupy about 20% of the total area, boundary layer and turbulent flow effectively cut the air flow to about 50% of a free space comparison. Free space as in a screen free door. Which is only practical if the mosquitoes and other bugs are on vacation. Or, in an emergency. From my recollection, in a screen free situation, placement of the fan in the doorway was more effective than at a distance from the door. I think I could explain why your solution works better for a window with a screen if you want me to elaborate.

[@celestiallia]

Thank you so much for this video!! My apartment has been waaayyy too hot for the past week (1 bedroom apartment) and it turns out your fan placement tips have been able to cool it down significantly within just a couple minutes! I just changed the placement of my fan and my apartment feels so much more ventilated and it actually cooled down a bit! Thank you so so much!!

[@doka-sp]

I watched this video around the time that it came out and having a house with no HVAC means this was legitimately life changing for me to be able to keep my room cool all this time Thank you for this!

[@VanGoWanderlust]

Can you do more tests? This is so interesting. I’ve been using a fan to blow cold air from downstairs to up stairs. One from the basement to first floor, and one from the first floor to second floor. I FEEL like it helps a lot, but would love to see scientific data like this. ☺️

[@arjovenzia]

In my house, I've found the best place is actually in the middle of the house. I use a portable evaporative system in the doorway to the wet space (shower/toilet/laundry). lots of air intake, and a nice open run in and out of the fan. being in the doorway, there is very little air bleeding around the fan. having the fan at the other end of the hall helps keep it quiet, and pumping cold air down the hall keeps the brick from getting warm, which really helps in a heatwave. a few pieces of thread taped to a skewer is a really useful tool to figure out placement of fans, and if you get it right, it makes a huge difference. I'd really like to see what sort of difference an external evaporator over the hot side of my AC makes, Im thinking of a sheet pitched like a tent about 1-2ft away from the external unit with a mist spray on it. however, I only use my compressor AC on REALLY hot days (above 36 usually), as the evap/fan setup works well enough. and if I deem it worth switching on, I sure don't want to be out there messing around with it. would be interesting to know how much power can be saved at the expense of some water.

[@MindCaged]

This totally works, I saw several videos of this in the past and tried it myself. I didn't do all the air speed tests, but it changes it from taking an hour or more to cool my room with only a slight temperature change even when it's like in the 60s outside to bare minutes. Obviously the colder outside the faster and bigger the effect, but just the shear difference between having the fan in the window sill versus like 2-3 feet back made a huge difference in cooling my room. A whole house would be slower since it's a much greater volume of air that has to be moved but it would still have a much greater effect. My basic understanding of the reason is basically that by putting some space between you're increasing the volume of air from inside that can be pushed outside, that with the greater space more air will flow faster into that space than will just flow into the back of the fan.

[@DaveXYZ369]

3 Years to late but here are my 2 Cents on it: i open all my Windows and figure out how the air moves and then place in the areas that are blocked of the windows, the fans so that the natural flow of the air that is coming through is not disrupted but supported. Always worked for me. Greetings from Germany.

[@rronmar]

Great demonstration of induced flow. Air molecules have friction when working against other air molecules. A column of air will pull other air along with it. The window serves to focus this and varying the distance finds the area of largest effect. If this area is applied to the window, it will create a negative pressure in the room. Opening all the other windows will help reduce the drag/resistance to the flow toward the negative pressure. But you need to plan ahead a little and must put the fan on the downwind side of the house as A little breeze toward the outflow window will pretty easily cancel out your inducer. Cooling a house with outside air is all about moving mass and induced flow from a fan is probably the simplest way to do it. I use an old blower out of a portable air conditioner as it is fairly quiet, but delivers a nice focused airstream to develop the induced flow… i like conclusive data also:)