We found single-fan models too powerful and too bulky, and the slimmer three-fan models too weak.
Two-fan design: In our research and testing, we found that models with two internal fans struck the best balance of power and size for most windows.
An electrically reversible fan can do that with the push of a button.
Electrically reversible: Some fans require you to physically remove the fan, turn it around, and reinstall it to change the direction of the airflow.
