Daylighting

Daylighting is the practice of placing windows or other openings and reflective surfaces so that during the day natural light provides effective internal lighting. Particular attention is given to daylighting while designing a building when the aim is to maximize visual comfort or to reduce energy use. Energy savings can be achieved either from the reduced use of artificial lighting or from passive solar heating or cooling.
Daylighting is a technical term given to a common centuries-old, geography and culture independent design basic by 20th century architects, many of whom who had made inadequate use of the design due to low cost and ignorance of global warming issues.
There is no direct sunlight on the polar-side wall of a building from the autumnal equinox to the spring equinox in parts of the globe north of the Tropic of Cancer and in parts of the globe south of the Tropic of Capricorn. Traditionally, in these parts with largely overcast skies, houses were designed with minimal windows on the polar side but more larger windows on the equatorial-side. Equatorial-side windows receive at least some direct sunlight on any sunny day of the year, so they are effective at daylighting areas of the house adjacent to the windows. Even so, during mid-winter, light incidence is highly directional and casts deep shadows. This may be partially ameliorated through light diffusion and through somewhat reflective internal surfaces.

Another type of device used are light tubes, also called solar tubes, which are placed into a roof and admit light to a focused area of the interior. These somewhat resemble recessed light fixtures in the ceiling. They do not allow as much heat transfer as skylights because they have a less exposed surface area.