That's probably true. But it's also appealing that they are low wattage. I ended up using one of these fan's that I've had around . You need a 12v DC power source or an ac/dc converter (I wouldn't attempt to run it on normal household ac outlets since there's an actual warning but it might work). I hook it up to a modest solar setup and it will run all day using only 7 watts. Box fans are rated at around 60 watts for perspective.
https://www.amazon.com/gp/product/B00TWCRZX2/ref=ppx\_yo\_dt\_b\_search\_asin\_title?ie=UTF8&psc=1