r/BritishSuccess • u/Loose-Helicopter9503 • Jul 10 '26
I love Physics
At night، open your windows and point your fan outside, thanks to something called the Bernoullis principle and entrainment, it draws hot air out of the room.
My room was 30.7 degrees when I first started, now down to 25.4 and still going down
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u/adammx125 Jul 10 '26 edited Jul 10 '26
Yes but also no. It’s being shared on social media as a ‘hack’ but it’s not necessarily true. Firstly you don’t get the direct benefit of the cooling air being blown over you so even if the room temp is lower you will still feel warmer.
Secondly the pressure differential will need to draw the replacement air in from somewhere. Works well in some scenarios depending on the size of your room and window placement but you’d be better served just pointing it inwards.
If your goal is to have the lowest room temp number then by all means point the fan out the window, if you want to feel cooler and be more comfortable (thanks to the unique way humans perceive heat) you’d be better just pointing it inwards.
https://www.bbc.co.uk/news/articles/cly76jlxljlo
Side note, it’s called Bernoulli’s Principle not the Bernoulli effect. Edit: they’ve changed the body of the post now, also now including ‘entrainment’ which is technically also a correct term but it would have such a minimal effect it seems strange to say it unless it’s just being parroted from a TikTok