The use of natural light in interior spaces, sometimes called "daylighting," has a plethora of benefits. It can increase occupant productivity and comfort, provide mental and visual stimulation, boost occupant mood, and can even dramatically reduce energy costs. Sometimes, though, it can be difficult to incorporate traditional windows in a space for practical or aesthetic reasons. In other cases and environments, traditional windows may bring in strong, direct sunlight when filtered or indirect sunlight is actually desired. So, it can be tricky.
Indeed, a common problem with regular windows is the inability to control the quantity of light that enters a space, often creating a glare in the room or perhaps heating up the space to the point where air conditioning is necessary.
In many of these cases, there are in fact architectural solutions to harness and control natural light so that it can best serve a space’s inhabitants. Here, we take a look at five of these methods.
A light shelf is a horizontal, shelf-like element that's usually positioned above eye-level on a window so that it can bounce light from outside off the surface of the shelf. In doing so, the light shelf reduces glare and distributes light more evenly, and actually doubles the effective depth of incoming light.
Light shelves can be located on the interior, exterior, or on both the inside and outside of a building, and can be integral with a window or mounted onto the facade of a building. Usually, they're most effective on the walls that face the sun’s path—often the southern facade in the northern hemisphere. However, even on the east and west facades, where they aren’t as effective at bouncing light into a space, they can help reduce direct heat gain and glare.
A skylight is a non-traditional window that, as its name implies, looks up to the sky and is usually placed on the roof of a building. Skylights are typically fixed, meaning that they can’t be opened or closed, but occasionally skylights are operable or even completely retractable. They can be an extremely effective way to promote natural light, especially in spaces that don't have any traditional windows.
However, their location on the roof means that they're more vulnerable to leaks and damage from sunlight and falling debris, and it can be difficult to control the amount of sunlight that enters a space. To avoid generating too much heat from a skylight, it's best to correctly locate the skylight so that it's not in the direct path of the sun.
A sun tunnel, also known as a tubular daylighting device, is similar to a skylight in terms of the location on the ceiling or roof of a space or building. However, they're more high-tech in that they're coated on the interior with reflective materials or pipes, and then topped with a clear plastic dome so that they can effectively draw in as much light as possible, despite their small surface area.
While skylights have difficulties controlling the quantity and quality of incoming sunlight, sun tubes reduce glare and inconsistent light patterns and screen infrared sun rays because of the type of glazing they have. This means that they reduce solar heat gain—but also, furniture and fabrics won’t get bleached by the sun.
Another valuable way to bring more light into a space is to reduce furniture and solid doors that might block light from passing through. By replacing solid doors with glass doors, French doors, or simply openings with no door, light can transmit from one area to another without any help.
Of course, the use of transparent materials in doors isn’t appropriate in all spaces, but even translucent or frosted glass can provide a surprising amount of light in spaces that were previously closed off from direct sunlight. It's important to also remember that glass reflects light, so even opaque glass can increase light reflections.
Finally, one type of non-traditional window that has excellent daylighting and ventilation benefits is the clerestory window, a window high up on a wall that's well above eye level. Historically, clerestory windows were used in churches where the upper level would have a row of windows to bring in daylight in what would otherwise have been tall, dark stone structures, but today, they're a common element in energy-efficient buildings.
Because of their location high up on a wall, they bring light and breezes into a space, but without compromising privacy. Ideally, clerestory windows should be located on the sunny side of a building, but still protected from the summer sun by rooflines, louvers, overhangs, or other light-mitigating strategies. Clerestory windows can also be a critical part in the passive cooling of a home, so the benefits are multifold.