I have a 1200w aircon in a 6 X 3 X 8 room and it is total overkill, even when it is 100F degrees outside.
evaporative cooling works well in smaller areas so it might be good. for $30 bucks it is worth a shot. climate control is always my main focus when producing quality yields. However, dont expect great climate control on a such a simple device. expect 10-15% differences at best.