Sounds similar to the concept of a swamp cooler to me; maybe look up how they calculate efficiency?
Also, swamp coolers are only effective below a certain temp, so you’d need to think about bypassing (cutting the fan and turning on air con) above a certain threshold
You got me curious since it’s been ages since I uninstalled Reddit and it’s actually crazy how much more invested I am in Lemmy comments. Feels like all the Linux communities are actually helpful and full of real world experience, not to mention the flashlight community. Definitely a good reminder to set up a recurring donation to the smaller instance I use