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

This kind of thing is why KZfaq exists.

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

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

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

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

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

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)

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.

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

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

Wife on vacation "He's probably bringing random girls home while i'm away"

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

This is like overclocking home edition

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

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.

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

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

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

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!

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!"

When I was a kid living in Austin, TX, we had no AC and brutal summers and we used fans for cooling... I’d turn the sheet on my bed into a diamond shape and tuck the corners under the mattress, leaving gaps on the straight pieces of top sheet, tie the foot end of the sheet to the handle of the box fan in the window, and turn the fan on. It blows up the sheet into a tent, circling the cool air around you (especially great at night), but the gaps allow some air to escape so the sheet won’t blow completely off the bed. TLDR; livin in the year 3000 back in 1978

It's not as powerful as I thought it would be, but it works very well. kzfaq.infoUgkxGjG43--gYqIoT4Xkur2PqCrtbKwTv2h6 There are three options to circulate air, and best of all a remote control for us lazy people. Installation was a breeze (no pun intended). It actually took longer to open the box then it did putting the side extenders on and sitting it in the window opening. It's a perfect alternative when you want airflow, but not the AC. Just might order another one for a different room. UPDATE: Bought another one like I said. They work great. Why not have two...

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!

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

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

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.

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

As someone who sleeps in an attic room with no air con this is vital data, thanks.

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.

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!

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!!!

dude its summer and you just made my bedroom noticeably cooler

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

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!

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!

This is an AWESOME experiment!

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.

I love these independent experiments with useful information

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

You don’t search for this.

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.

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!

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

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!

Trust anyone with a raspberry pie laying around for experiments.

I love the way you hooked up those devices and experimented with placement. I admire your skills! I’m watching this from England, where the weather is just warming up.👍

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.

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

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).

Sir, your commitment and follow through on your musings is highly inspiring.

I was troubling over this question just last week. Very good video. No "educational" bloat. Just good solid content. Thanks!

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.

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

Enjoyed this. This is the kind of quality content I’ve grown to forget. Sometimes KZfaq algorithm does good things.

I often sneak a cigarette at home and I must say that placing the fan in the middle of the room in comparison to right next to the window has yielded better results for me. I point the fan straight at the window and use the full power mode and the cigarette smoke and smell clears within 5 minutes. The best results occur when a second window is opened directly behind the fan.

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.

and im impressed by those big digit console output.

Too good! As someone slightly obsessed with using fans efficiently for total home air exchange…this really hit the spot.

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 !

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

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.

Tis video is amazing. I've been testing methods in my appartment for days now. The best one so far made for a slight breeze. This method had the 1 fan right up against a window. I decided to move it back about a meter and now i am blowing of my couch. Thank you so much

I remember watching this video when it first came out. Was lucky enough to get recommended it out of nowhere. It was a nice change of pace. Now, I'm trying to setup some cross ventilation in my home and I kept thinking of this video. Everything comes around eventually.

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.

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

This is one of the most informative videos I've seen. So simple but so complete. All hail KZfaq and people like this guy!!!

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

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! 👍

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.

I love the engineering discipline you use. This is really useful stuff! Thank you

I watched this eons ago. I had to search for it again because I couldn't remember the results of the experiment. Great stuff.

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

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

Love that you did the math.. I kind of reached same conclusion trying to move air from front door to back door, i.e. pushing at the backdoor at ~1meter distance seemed to do the most

That was some detailed experiment, and very useful, I've always used the fan the wrong way, having it blow inward, which is terrible, thank you sir!!

"I love clean data." I felt that.

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

I’ve never seen a YT channel as entertaining as this one before.

This is incredibly insightful for us fan users. Thank you for your work!

Every 40 year old woman: WHAT GOOD IS THAT I NEED IT BLOWING ON ME

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.

I have an outside generator shack that has to be ventilated when the generator is in operation. The ventilation is needful both to cool the inside of the shack (and thus the cooling air available to the engine) and to supply fresh air for the engine to use for combustion. I've been playing with/experimenting with fan placement trying to figure out how the best airflow is accomplished. Preferably without sucking exhaust fumes back inside the shack. The information in this video is very useful towards that end. I have no way to gauge the airflow in and out of the structure. Thank you for taking the time to put this together.

This video follows the Bernoulli's principle If you dont know how this works just youtube another simple experiment or what it does it as the air you blow follows a laminar flow the surrounding air also gets involved in the flow and flows through a given path Hope this helps❤

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.

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!

Thanks, really appreciate that there is no extra comments, only the essentials. And that would help a lot here!

I have no ac in my home and every year I end up putting fans in different areas, and hoping it will keep me cooler than the year before. Now I know where to put them to be the most efficient! Thank you so much!

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.

Been doing this for years just on a hunch from my fluid dynamics days that it was probably better. Good to see some actual data! Thanks for sharing it.

Today ive spend 4 hours watching KZfaq and your video is the only one ive found genuinely interesting and would affect my life.

I love it when the data supports my experience. Good Job

Something tells me he just had a huge fight upstairs with his wife.

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.

I used your research to cool off my bedroom before going to bed tonight. I put the fan about 2' from the window and it worked perfectly. Thanks!

i loved your experiment, i am too experimenting with blowing hot air out of the house during summer to keep it cooler, your video helped! thanks.

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

One big reason putting the fan far away from the window works better is because of the Venturi effect. When the air speeds through space, it creates a low pressure zone that pulls in more air around it.

I've now got my only fan in this hot room facing outside the sliding door, hoping for the best.

Thank you KZfaq recommendation! It’s so hot in the Philippines. Will try this when I get home.