Daylighting is natural light from windows, doors and skylights that adds a warm, inviting quality to a room, as well as giving the room a feeling of openness. The following are tips for planning daylighting:
• Determine when the bathroom is used most. Emphasizing natural light when the bathroom is only used at night or in the early morning may not lead to logical or cost-effective planning.
Too much natural light can also lead to glare. If the window area faces a sunny direction, incorporate window treatments that can help control the bright sunlight during certain times of the day. The bright sun could cause glare on mirrors if not properly placed.
Large windows and glass doors to the outside can provide adequate daytime lighting needs (see Figure 7.11), plus visually open the room to the outdoors.
• Windows and glass doors below 18 inches (457 mm) will need to be made of tempered glazing. Windows that surround a bathtub or shower should also be made of tempered glazing. See information in Bathroom Planning Guideline 15, discussed in chapter 6, "Bathroom Planning."
• Skylights (see Figure 7.12) can add natural light without sacrificing wall space, but be sure to select high-quality skylights and have them installed properly. Skylights provide about five times as much light as a comparably sized wall window.
• Select windows or skylights that have a high insulating value to keep the bathroom more comfortable year-round. Also study air leakage rates, and select windows or skylights that are rated as having low air leakage. More information on window ratings and selecting energy – efficient windows can be found in chapter 2, "Infrastructure Considerations," and chapter 3, "Environmental and Sustainability Considerations."
Privacy is another consideration when incorporating a large amount of glass in a bathroom. Privacy measures on the exterior of the windows, or adequate window treatments, are necessary to protect the privacy of the bathroom users. Some decorative fixed windows may look attractive but can also allow a view into the bathroom if not placed high on the wall. Covering decorative windows placed in the walking path of the room takes away from their aesthetic appeal. Glass block is a popular way to incorporate light without a need to be concerned about privacy.