Ceiling fans with lights are mounted on the ceiling of a room or space to provide an integrated solution for air circulation and illumination. Hub-mounted rotating blades, driven by a DC motor or an AC motor, are used to circulate air. DC motors are more efficient than AC motors and allow virtually silent operation. They have more speed options and generally respond faster to control commands. AC fan motors boast greater reliability and tend to be less expensive than DC fan motors. Ceiling fans push cool air downward and clockwise to cool the space during the summer. Some ceiling fans come with reversible motors which can adjust the direction of the blades to circulate trapped warm air near the ceiling during the winter. The light kit used to be a light assembly designed to accommodate light bulbs.