Now when he was gone out, his servants came; and they saw, and, behold, the doors of the upper room were locked; and they said, Surely he is covering his feet in the upper chamber.
The room in which Ehud met Eglon (Judges 3:20) was on the flat roof of his house. Rooms built this way caught the prevailing currents of air and therefore provided a cool place of retreat from the hot weather.