Since the oil crunch of the 1970s, architects, engineers, and homeowners have sought new ways to reduce America’s reliance on traditional energy sources for heating and lighting homes. Certainly one of the most popular and promising answers to emerge has been solar energy. “Although nobody has officially counted, we project there are well over half a million passive solar houses in the United States,” according to the Passive Solar Industries Council.
With the solar heating movement, a less known but highly regarded design science has stepped to the fore—“daylighting,” the use of natural light to illuminate building interiors. Of course, this concept is as old as the window itself, but relatively recent advances in lighting research, window and glazing technology, and lighting controls have opened up new horizons for daylighting. We know that homeowners love the qualities of natural light—billions of dollars are spent each year on remodeling, often in an effort to achieve more light and spaciousness. But how far should homeowners go? The answer seems to be this: You can enjoy and benefit from more natural light by taking advantage of selective daylighting principles and materials, but comprehensive daylighting systems don’t make sense in most homes.
For one thing, the potential energy savings are not the same as for commercial and institutional buildings. Though houses do use plenty of electricity for lighting, high-wattage electric appliances and heating are what gobble up a healthy share of a home’s power needs. And there’s the issue of occupancy. Unlike an office or library, many homes are relatively unoccupied during daylight hours, which shifts a larger percentage of electrical usage to the evenings.
Control is different, too. At home, it’s easy to flip off the lights when they’re not needed. Sophisticated controls that automatically raise and lower indoor artificial light levels according to daylight are not necessary.
Providing natural light in houses is often fundamental to their design. As Russell Leslie and Kathryn Conway point out in “The Lighting Pattern Book For Homes,” published by Rensselaer's Lighting Research Center, “Homes often have generous amounts of daylight, and residential building codes require that most rooms have windows. Typical residential rooms are small enough so that daylight can reach deep into the room, particularly if windows are located high on the wall.”
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