A shelter is a structure that provides protection from the environment. Shelters provide a covering from wind, rain, and snow, provide warmth and cooling during extreme temperatures, and a safe place to eat and sleep. Along with water and food, shelters are one of the basic physiological requirements for life.
For most humans, this need is satisfied with a permanent structure called a house, which are heated, cooled, supplied with energy, drinking water, and a method of removing sewage and other waste, all of which can be designed to combat or work with the local environment. Constructed homes typically have a floor that is enclosed by walls that support a roof, each of which have important design considerations.