The Most Important Reason Is Smoke
The strongest reason behind the towel trick is not comfort. It is safety during an emergency. In a fire, smoke can spread quickly through hallways and under doors, sometimes before flames ever reach the area. This is why emergency advice often focuses on keeping doors closed and blocking gaps where smoke might enter. If someone cannot safely leave the room because the hallway is smoky or dangerous, sealing the gap under the door with wet towels, sheets, or clothes can help reduce smoke coming inside.
Of course, a towel is not a replacement for alarms, sprinklers, evacuation plans, or calling for help. It is not the first step in an emergency. The closed door does most of the work, and the towel only helps cover the lower opening. Still, because the trick is so simple, it is easy to remember. A normal bath towel may seem ordinary, but in the rare moment when smoke is outside the door, it can become a quick way to make the room a little more protected while waiting for instructions or help.
