Yes. One box fan pointed in is just pushing against a wall of air that has nowhere to go. It's completely possible for a fan to be spinning but move essentially

Yes. One box fan pointed in is just pushing against a wall of air that has nowhere to go. It's completely possible for a fan to be spinning but move essentially no air. One pointed in and one pointed out gives that wall of air somewhere to go, which means the fan pointed in is able to push more air in.