Put the box fan in the window, blowing outward

The best way to position a box fan in a bedroom is in an open window, facing outward, to exhaust the hot air.

Most people set a box fan on the floor or on a dresser, pointing at themselves. That only moves the air around the room, recirculating the same stale heat. If the air in the room is already warm, you’re just giving yourself a warm breeze.

Put the fan in the window, facing out. It will pull hot air out of the room and create negative pressure. Air from the rest of the house (or from another window you crack open) will get sucked in, creating actual cross-ventilation. If you only have one window, crack your bedroom door a few inches to let replacement air flow in. This works way better than pointing the fan at your face.

If it’s cooler outside than inside (like at night), flip it to blow inward. But for daytime cooling, exhaust is the move.

This is the closest thing to air conditioning that costs ten bucks to run all month.