Residential real estate ads typically emphasize natural light — “Lots of windows!” “Southern exposure!” “Bright and cheerful interior!” Bringing light indoors is an important quality to consumers. Studies on natural light have shown it to elevate moods as well as reduce energy use. But incorporating natural light into a design isn’t as easy as just adding a few windows.
“The first thing to remember,” says Ann Arbor architect Michael Klement, “is that there is a difference between sunlight and daylight.” Sunlight is something you want to temper. Streaming into a space, sunlight can be dramatic, but if it’s not controlled, you’ll have excessive heat gain, glare, and deterioration of products from ultraviolet exposure. “Of course,” Klement says, “sunlight, if harvested correctly, will help in energy-efficient heating, but that’s another story.
Daylight has the color temperature that tends to elevate our spirits. It’s varied and not constant illumination, which can add a certain drama to a space. These [attributes] are what people like most about natural light.”
Let There Be Light
In the beginning there were windows, and that was good. But window placement rather than window quantity is what’s important. “Position windows near corners, near adjacent walls,” Klement says. This will help increase natural light because the walls will act as light multipliers. “A wall can be illuminated and/or a wall will act as a reflector to drive light further into the space.”
Another way to gather more light is with a light shelf — a soffit, for example. If windows are along a building’s southern plane, a light shelf placed at about door head height will bounce the light off its surface onto the ceiling and into the space.
Aside from traditional windows, skylights and light tubes can also bring in natural light. Skylights usually admit untempered light, so Klement recommends using a sun control device such as venetian blinds or roller shades. This will help manage the energy/heat component. “If you block the sunlight before it passes the plane of the glass, you’re blocking the shortwave radiation,” Klement says. “Once the light goes through the glass and strikes a surface it changes to longwave radiation, and that’s where heat develops.”
In southern climates it might be possible to shade a skylight externally. (Companies such as Velux and Hunter Douglas make exterior shades.) “But in my climate [Michigan] I’d be concerned how a mechanized component outside a building would perform in the winter,” Klement says. Sometimes he’ll use a skylight/window hybrid, with the glass turned vertically on the roof plane. “You get a lot of light penetrating the windows, but not at perpendicular angles to the sun. That light is too intense.”
Light tubes, often called sun tubes or sun pipes, are “outstanding for harvesting light,” Klement says. Used most often in “captured rooms” — any room lacking an exterior light source — light tubes are transparent pipes with one end on a roof and the rest snaking through a home to a dark space. Often the tube has reflectors or lenses to help spread the light.
Remember that the tube brings in light 24/7. A lightning flash can illuminate the space. If placed on the south side of a roof slope the tube collects sunlight; on the north, daylight. And there will be light degradation depending on the distance the light travels in the tube.
Follow The Sun
Be mindful of the reflective qualities of light — in a media room, too much light can hamper TV viewing, or a shiny dark granite countertop may become unusable from glare. Most CAD software will show you where sunlight will fall in a home, and you can find solar path charts such as those developed by the University of Oregon that help you plot the sun’s course over a particular location.