Ways Daylighting Can Improve Performance

Daylighting is the controlled admission of natural sunlight into a building via diffused skylights or windows. Done correctly, it can save energy and money by reducing the need for artificial electric lighting during daylight hours without causing heating or cooling problems.You can gain value from the opportunity daylighting provides in construction projects for not only energy savings, but additional business and lifestyle improvements.

Increasing Student Productivity

Electric lights account for 30-60 percent of the total electrical energy consumption in commercial buildings. For many institutional buildings, strategic daylighting can reduce total energy costs by as much as one-third because it uses sunlight, a resource that costs $0 to produce, reduces loads imposed on mechanical cooling equipment, reduces waste heat, contributes zero greenhouse gases to the environment, performs at 100 percent on the Color Rendering Index (CRI), and will be around for another five billion years.

As a result of daylighting, educational facilities continue to see improvement in areas other than just their energy bills. The bright and airy atmosphere created by daylighting has been proven to increase grades and work performance. In educational settings, daylighting has been shown to increase productivity, improve grades and reduce absenteeism. A study initiated by the Pacific Gas and Electric Company (PG&E) showed that students with the most daylighting in their classrooms progressed 20 percent faster on math tests and 26 percent faster on reading tests in one year than those with the least. The study found a uniformly positive and statistically significant correlation between the presence of daylighting and better student test scores.

Numerous studies link daylight and views of the outside to higher levels of satisfaction and productivity in the workplace. Businesses who utilize productivity-focused energy-efficiency measures view them as a distinct competitive advantage. The PG&E study showed that office workers in a daylit atmosphere performed 10 to 25 percent better on tests, improved recall, improved employee morale, and showed more satisfaction with their work environment.

Athletic Facilities Reap Benefits

Athletic facilities can also benefit from daylighting, significantly reducing energy costs and creating a more inviting environment. Reducing dependence on artificial light during operating hours leads to various operational cost savings. Given that these types of buildings are typically very large in size, daylighting can easily be implemented and highly effective. For educational buildings the typical daylighting roof area percent per building use is 4-5 percent and for athletic facilities is 5 percent to provide enough daylighting.

One thing to be careful of is that hail can cause major damage to a structure, more than $1 billion in damages in the United States annually. The best way to prevent hail damage is to make sure your building’s roof and roof components are as impact resistant as possible. Traditional skylights often do a poor job of dispersing the sun’s rays, causing hot spots, glare UV damage and uncontrolled heat. By completely diffusing incoming sunlight, prismatic skylights refract the light into micro light beams, spreading the sun’s bright, natural light around the space. This reduces the sun’s intensity without compromising daylighting effectiveness.

A Variety of Available Skylights

Standing Seam Integrated Prismatic Skylights: These are the ideal solution for daylighting in new construction when using popular standing seam metal roofing systems. Manufactured as a complete unit, the integrated skylight is factory-mounted right to the trapezoidal panel and seamed in place along with the rest of the roof during construction. This product comes double glazed as standard and is manufactured from two layers of durable high-performance polycarbonate.

Curb Mounted Prismatic Skylight: These can be used in new construction and in retrofit applications. The double-glazed acrylic over acrylic prismatic dome is sealed with a silicone and urethane seal between the prismatic lenses before it is fully welded with encapsulating and insulted thermal break. With no exposed metal, there is no condensation from thermal bridging through the frame. The pre-installed foam curb gasket and curb weather sweep mitigate condensation concerns. This frame then sits on a curb and is screwed in with stainless steel screws with rubber washers. With all skylights, the dome shape is designed to optimize lighting performance even at low angles-with no moving parts.

The resulting performance provides better quality light for the maximum hours per day, thus maximizing energy savings by greatly reducing electric lighting use. Prismatic skylights use the highest UV resistant materials available insuring high visible light transmission for the life of the product. Based upon scientific data from ASTM testing, this skylight will not reach a Y-20 on the yellowing scale during its life. Any yellowing below Y-20 is not visible to the naked eye.

Daylighting Is More Than Skylights or Windows

Three critical components of effective daylighting include the following: (1) Energy efficient skylights and/or windows; (2) LED lighting systems; (3) Lighting controls. LED (Light Emitting Diode) is the most efficient lighting technology avialable today.

It is estimated that switching to LED lighting over the next two decades could save the country $250 billion in energy costs over that period, reduce the electricity consumption for lighting by nearly one half and avoid 1,800 million metric tons of carbon emission.

LED lighting is gaining popularity due to the growing energy conservation movement and advances in technology, making LED lighting a cost-effective, clean and ecofriendly way of illumination.

Combining LED with Lighting Controls

Combining LED with lighting controls like electric light dimming systems offers energy savings as well as compensation for reduced output to give constant light level over time and control over adjustments to light level for any space. Implementing daylighting goes beyond cutting a hole in a roof, but requires an integrated approach to be successful. Effective daylighting requires decisions about the building form, location, climate, building components and lighting controls.

In return, properly daylit buildings can repay installation cost quickly-often in less than five years. Daylighting can be installed in buildings to replace electric lighting for 1/20 of the cost of enough solar PV panels to generate an equivalent amount of electricity using the same sun at the same high energy demand times of the day.

About the Author
Wes Brooker -- Marketing Manager with Nucor Fabricated Products -- is responsible for strategic growth and communication programs for Nucor Corporation steel products companies. His areas of expertise include marketing, business strategy, top line growth, green and sustainability programs and Building Information Modeling.