Box fans can dry a wet carpet — if you use them right.

Box fans can dry a wet carpet after a spill, but you have to set them up properly and manage expectations.

The short version: they move air, which speeds up evaporation. That’s the whole game with drying a carpet. But a box fan is a general-purpose fan, not a carpet dryer. It’s fine for small spills (a few cups of water or a pet accident), but it’s underpowered if you’ve got a soaked area larger than a couple square feet.

The trick is getting the air to actually flow across the wet carpet fibers. Don’t just point the fan at the puddle from three feet away — that mostly just blows air over the wet spot. Instead, lift the carpet slightly off the pad (put a piece of wood or a spacer under the edge) and aim the fan so it forces air under the carpet. That’s where the moisture gets trapped. Also, blot up as much water as you can with towels first. The fan can’t do everything.

If the spill goes deep into the padding, a box fan alone probably won’t dry it fast enough to prevent mildew. You’d need a proper air mover (like a carpet cleaning machine rental) or a dehumidifier in the room. But for a quick coffee spill or a small leak? A box fan aimed right will get the job done in a few hours.

Just don’t expect it to work miracles on a flooded basement. That’s when you call a pro or rent real equipment.