Passive solar design begins with building orientation. This means that windows should be placed to face north and south, avoiding direct exposure to the sun's daily passage from sunrise in the east to sunset in the west. This diagonal orientation allows us to manipulate sunlight, shade and their seasonal fluctuations toward the creation of thermally comfortable indoor and outdoor spaces that require little or no mechanical energy to operate.
South-facing windows provide natural light that gives people a sense of warmth and psychological well being. Light from the north is cool and logical. North and South-facing windows can be shaded so that they collect low-slanting winter rays while keeping out blasting summer light. These shades can be used as reflective light diffusers to direct superior natural light into interior spaces.