page_title: Daylighting
section_title: Translucent walls
hierarchical_section_title: Daylighting / Types / Translucent walls
caption_attribution_description: English: a Bottle Wall of an Earthship Bathroom
context_page_description: Daylighting is the practice of placing windows, skylights, other openings, and reflective surfaces so that sunlight can provide 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 from the reduced use of artificial lighting or from passive solar heating. Artificial lighting energy use can be reduced by simply installing fewer electric lights where daylight is present or by automatically dimming/switching off electric lights in response to the presence of daylight – a process known as daylight harvesting.
  The amount of daylight received in an internal space can be analyzed by measuring illuminance on a grid or undertaking a daylight factor calculation. Computer programs such as Radiance allow an architect or engineer to quickly calculate benefits of a particular design. The human eye's response to light is non-linear, so a more even distribution of the same amount of light makes a room appear brighter.
  The source of all daylight is the Sun. The proportion of direct to diffuse light impacts the amount and quality of daylight.
context_section_description: Walls made of glass brick are translucent to transparent. Traditionally, they are hollow and grouted with a fine concrete grout, but some modern glass brick walls are solid cast glass grouted with a transparent glue. If the glue matches the refractive index of the glass, the wall can be fairly transparent.
  Increasing the amount of concrete, bottle walls embed bottles that run right through the wall, transmitting light. Concrete walls with glass prisms running through them have also been made. With the advent of cheaper optical fibers, fiber-optic concrete walls. Daylight (and shadow images) can then pass directly through a solid concrete wall, making it translucent; fiber optics will lead light around bends and over tens of meters. Typically only a few percent of the light is transmitted (the percent transmittance is about half the percent of the surface that is fibers, and usually only ~5% fibers are used).
  Both glass and concrete conduct heat fairly well, when solid, so none of these walls insulate well. They are therefore often used outdoors, as a divider between two heated spaces (see images), or in very temperate climates.
  Greenhouse walls (and roofs) are made to transmit as much light and as little heat as possible. They use a variety of materials, and may be transparent or translucent.
caption: Bottle wall
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