Daylighting is the use of windows and skylights to provide supplemental lighting, in the form of direct, diffuse, or reflected sunlight, for building interiors. This is an aspect of passive solar energy relevant to every home.


Today's highly energy-efficient windows, as well as advances in lighting design, allow windows to be used very effectively reduce the need for artificial lighting during daylight hours without causing heating or cooling problems. The best way to incorporate daylighting in your home depends on your climate and home's design. The sizes and locations of windows should be based on the cardinal directions rather than their effect on the street-side appearance of the house.


South-facing windows are most advantageous for daylighting and for moderating seasonal temperatures. They allow most winter sunlight into the home but little direct sun during the summer, especially when properly shaded.


North-facing windows are also advantageous for daylighting. They admit relatively even, natural light, producing little glare and almost no unwanted summer heat gain.


Although east- and west-facing windows provide good daylight penetration in the morning and evening, respectively, they should be limited. They may cause glare, admit a lot of heat during the summer when it is usually not wanted, and contribute little to solar heating during the winter.


If you're constructing a new house, you want to consider daylighting as part of your whole-house design – an approach for building an energy-efficient home. Since advanced windows can provide daylighting in a home with little or no increase to yearly heating costs, the opportunity to increase daylighting in home design is much greater than ever before. In building design, however, one should be careful not to have too many windows and/or locate them improperly so that the building does not overheat, or add an unreasonable air conditioning load to the building.