Understanding Skylights

Windows are an essential part of our daily lives. Installed in homes, offices, and vehicles, they provide protection from the outside while offering views of the world. During daylight, windows allow sunlight to flood in, providing warmth in winter and helping to reduce heating costs when properly insulated. Sunlight also has a positive impact on our mood, as it boosts vitamin D and serotonin, chemicals that enhance happiness and energy. Those living in the northern hemisphere, especially those affected by seasonal affective disorder (SAD), require more sunlight in the colder months to combat feelings of depression. Sitting near a window can sometimes offer the best remedy [source: Kraft].

When you move a window upward and slightly tilt it, or place it directly on the ceiling, you create a skylight—a design element that amplifies natural sunlight, making spaces feel more airy and appealing. Skylights also offer ventilation options during warmer months, as many can be opened.

Skylights involve more than just cutting a hole in your ceiling and installing a pane of glass or plastic. They come in a variety of shapes and sizes, with different materials used for construction. The quality of the materials and the craftsmanship of the installation can impact key factors such as insulation and protection against leaks. Additionally, their positioning in your home determines how much natural light a room receives.

Skylight Materials

Skylights are usually made from plastic or glass, and the choice you make depends on several factors such as the climate, where the skylight is installed, and your budget. Manufacturers use the term glazing to refer to the type of material and construction used in skylights or windows.

Plastic glazing for skylights is more affordable than glass, but it is not as durable. Plastic is prone to scratches, discoloration, and warping. Unless treated with a special coating, plastic glazing allows harmful ultraviolet (UV) rays from the sun to enter, which can damage skin and fade furniture. If you've seen dome-shaped or bubble-like skylights, they are likely made from plastic, a design that is now considered outdated.

Glass glazing for skylights costs more than plastic, but it's generally preferred due to its superior durability, resistance to discoloration, and a more aesthetically pleasing appearance. Skylight glass must be made from safety glazing materials, which means it is either tempered or laminated. Tempered glass is heat-treated and cooled quickly to make it much stronger than standard glass, breaking into small, harmless pieces when shattered. Laminated glass consists of two glass panes with a thin plastic layer in between. Most skylights are constructed with tempered glass on the outside and laminated glass on the inside.

Different glazing methods can also improve a home's energy efficiency. Tinted glass can absorb heat and lower the solar heat gain coefficient (SHGC), which measures how much heat from the sun a window or skylight blocks. The ideal SHGC depends on your climate – the lower the number, the less heat enters your home. A skylight with a higher SHGC is more suitable for colder winters, while one with a lower SHGC is better at keeping heat out during the summer.

Skylights can also have low-emissivity (low-E) coatings, which are incredibly thin layers of metal applied to one or more of the panes. These coatings reduce the U-factor of a skylight, meaning they decrease the amount of non-solar heat that can enter. The lower the U-factor, the more energy-efficient the skylight is.

Skylight Safety

Skylights are commonly installed in bathrooms and kitchens. In the bathroom, a skylight provides natural light while maintaining privacy. Kitchens, where people spend considerable time cooking and eating, benefit from natural lighting, creating a pleasant atmosphere throughout the day.

When working near skylights, extra caution is crucial to prevent falls. Falling through a skylight can lead to serious injury, with the added risk of broken glass or plastic. Each year, around 36 fatal falls occur through skylights, and up to 50 nonfatal falls, mostly in construction settings [source: USGlass News Network].

To reduce the risk of falls through skylights, the American Architectural Manufacturer's Association (AAMA) recommends several safety measures. First, ensure that only trained professionals with roof safety experience are on the roof, especially during construction work. Many accidents happen due to other roof hazards, such as open holes, rather than stepping through a skylight. The AAMA also advises placing clear warning signs near skylights to alert anyone on the roof.

To provide additional safety, homeowners and building managers can install skylight screens or railings over their skylights, which cover the glass or plastic and help prevent accidental falls. These protective covers come in various styles and sizes, and are typically secured to the skylight with clamps or fasteners. Most screens are dome-shaped and designed to fit over bubble-style plastic skylights, though some are flat and may restrict the skylight's ability to open. Railings, while more noticeable, offer substantial protection but can be an obstruction for those walking on the roof.