The Importance of Daylighting

The term daylighting refers to the intentional and controlled admission of natural light into a space.

Considerations for skylight systems

By Mark Robins

Kingspan Mar19 1

Effective daylighting creates a more comfortable and visually stimulating environment. Many studies over the years have proven just how important sunlight is and the positive effects it has on humans and building complexes.

Research has proven that sunlight:

• Enhances our mood

• Improves our memory

• Allows us to view objects in their natural color

• Increases alertness and focus

• Improves overall health

When it comes to education, the California Public Utilities Commission noted improved results in reading, writing and learning when daylighting systems were installed instead of only side lighting. The commission also saw that students were able to complete their tests 20 percent faster and more accurately than in rooms with no daylighting systems installed. From a business standpoint, designing a building featuring daylighting systems can increase productivity and concentration, reduce employee turnover, improve short-term memory recall and increase sales in retail stores.

A well thought-out daylighting strategy is crucial to maximize the benefits of any daylighting system. Building orientation, unit size and location, understanding lighting needs, glazing material and performance attributes all impact the success of daylighting systems.

Lighting Control Benefits

Installing the right skylight and incorporating electric lighting controls will substantially save energy usage. Artificial lighting accounts for approximately 30 to 70 percent of a building’s energy consumption, so decreasing the need for artificial light can reduce energy consumption by up to 70 percent. Retail buildings offer the best opportunity for energy savings when utilizing lighting controls since most retail stores are open year-round and require high levels of light throughout the day.

When the daylight entering the building falls below the preset target threshold (usually 50- to 200-foot candles for retail), automatic lighting controls would restore power to the electric lights and turn them on to raise light levels back to the preset target threshold. These controls automatically dim or brighten all light fixtures within the daylight zone to maintain a consistent light level throughout the day.

Thermal Efficiency Versus Lighting Energy

Skylights and windows have notably lower U-factors than insulated roof and wall panels, meaning there will always be an imbalance when it comes to energy savings or losses. To minimize energy losses, in most climates the solar heat gain coefficient and U-factor of the skylight should be as low as possible. The reduced lighting energy use is directly related to the skylight’s visible light transmittance (VLT). The higher the VLT, the less lighting energy is used because more daylight is entering the building. Savings in lighting energy can amount to 10 to 15 times more than the losses in heating and cooling energy from installing skylights and automatic lighting controls.

Impact and Fire Resistance

Polycarbonate skylights are known to perform extremely well when it comes to impact and fire resistance. With an NFPA rating of CC1 (Class A) and a UL Listed Class 4 hail rating, polycarbonate skylights provide a safer roof when top-lighting is required. While long-term exposure to ultraviolet rays from the sun and lower visible transmission values have reduced total daylighting performance against industry standard acrylic prismatic skylights, advancements in today’s polycarbonate industry have increased the long-term performance of unit skylights to allow for greater building performance. To ensure any system will perform as advertised it’s important that the system be fully tested and certified in accordance with relevant building code requirements.

Longer Lasting Skylights

When selecting a daylighting product, it’s important to consider the system’s life span and maintenance requirements. The longevity of materials used in skylights has improved greatly over the years, allowing for a more reliable skylight system. Design changes have improved the reduction in visible light transmission and the skylight seal to the curb or roof deck, and also increased the durability of the skylight glazing itself. Further, there is an ongoing effort to update local and national building codes to guarantee performance standards over the life span of daylighting products. Manufacturers’ building code compliance gives architects and general contractors the peace of mind to specify these products with confidence.

Adam Toogood is marketing technologist, Kingspan Light + Air North America, Santa Ana, Calif. To learn more, visit

Kingspan Mar19 2