For Designers

Providing Daylight

Letting light into a house is an important function of windows. Even though people have become more reliant on electric light in their houses, good home design can provide most, if not all, the needed daytime light. The qualities of natural light are important even though the amount of energy that can be saved with daylighting is less significant in houses compared to commercial buildings.

The introduction of natural light is also a powerful architectural tool in shaping and defining the interior spaces. However, providing daylight requires thoughtful window placement and interior design that addresses a number of concerns such as visual comfort, balanced light levels, color, and fading of furnishings.

Guidelines for Providing Natural Light

• Arrange windows to provide daylight to all occupied rooms.
• Locate windows to define and enhance architectural volumes.
• Provide balanced lighting by introducing daylight from two directions in order to avoid glare and bright visual hot spots.
• Place windows so that direct sunlight, if admitted at all, reflects off interior walls and floors to provide more diffuse, even light.
• Use reflective ground surfaces or walls to increase daylight distribution into south- and north-facing windows.
• Avoid reflective ground surfaces that will increase glare from low sun entering east- and west-facing windows.
• Use translucent glazings on skylights to diffuse direct sunlight. Consider installing shutters or shades to block high midday summer sun while admitting daylight in morning, early evening, and on overcast days.
• Use light pipes to provide bright, diffused sunlight in a particular room location.
• Use landscape elements to block low direct sun into east- and west-facing windows.
• Use shades/curtains/overhangs to block direct sunlight.
• Use light from the north-facing windows to provide less variable, more diffuse illumination when desired.