Box fans: helpful, not magical

You can definitely use a box fan to help move air from an air conditioner, but it’s better for a single room or a specific zone than the whole house.

The problem is physics. A box fan pushes air in a straight line and loses pressure fast. You can aim it to shoot cool air down a hallway, but it won’t push into side rooms or around corners. What works better is placing the fan in a doorway to pull cool air from a room with the AC into an adjacent space. Or you can use it to help the AC’s return airflow — put the fan near the unit blowing toward the intake to help it pull air from further away.

If you’re trying to cool multiple rooms with one window unit, a box fan can help a little, especially if you set up a cross-breeze