The traditional houses of the Manchu were, for many centuries, similar to those of the Han. They were built in three divisions, with a central room used as a kitchen and two wings that served as sleeping quarters and living area. The sleeping rooms were heated by kangs, brick beds that could be heated in winter that were laid against the west, north, and south walls. Windows of the house opened to the south and west. The houses were warm in winter and cool in summer. Houses held a three-generation family, with an average size of seven or more persons.