Use a rug and clean the blades

To reduce box fan noise while sleeping, start by putting it on a carpet or rug to kill vibration, then clean the blades and lower the speed.

Most box fan noise is vibration rattling against the floor or case, not the motor itself. Set it on a bath mat, rug, or even a folded towel. That alone cuts the rumble by half.

Next, dust off the blades. A dirty fan is unbalanced — that wobble adds noise and wears the motor. Quick wipe with a damp cloth