Originally published in Mainebiz.
Maximizing natural light is a business strategy with multiple rewards
Dating back to Roman times, openings to allow natural light into a structure were an essential feature in architecture. But by the mid-twentieth century, due to the availability of cheap electricity and the popularity of fluorescent lighting, windows and other openings to the sky were no longer needed to illuminate interiors. Building codes that once required natural illumination changed to comply with the times. Consequently, new commercial and industrial buildings were designed with deep floor plans to maximize space and reduce construction costs. Daylight came to be viewed as an impediment to energy savings and a hindrance to a uniformly lit environment. But that perception is changing as studies reveal the triple bottom line benefits of increased daylighting.
Daylighting is the use of openings and reflective surfaces to take advantage of both sun and skylight to provide natural illumination to a building interior. And it is gaining favor as companies search for ways to save money on energy costs, reduce their carbon footprint and keep workers happy, healthy and productive — all at the same time.
When integrated with artificial lighting controls, daylighting can significantly reduce lighting costs while providing high-quality illumination. Lawrence Berkley National Laboratory, the nation’s premiere R&D facility for energy-efficient technologies, reports that lighting costs account for 35% to 40% of the total electrical energy consumption in commercial buildings and recommends daylighting as the most cost-effective strategy to reduce these costs. The National Institute of Building Sciences estimates that daylighting can reduce total building energy costs by as much as one third.
Daylighting can not only save money in reduced energy costs, it can generate income in the form of increased sales. Anecdotal accounts of the positive effects of daylighting on sales were given credence by two carefully designed studies commissioned by the state of California and conducted by the Heschong Mahone Group. In both studies, researchers found the introduction of daylighting through the placement of diffusing skylights increased retail sales in a particular chain store by an average of 40%.
These are some of the reasons retail giant Wal-Mart has made a commitment to include daylighting in its 200-300 newly constructed or converted facilities each year. Almost 600 Wal-Mart Supercenters, SAM’S Clubs and Neighborhood Markets integrate artificial lights with daylighting strategies, resulting in an annual savings of about 250 million kilowatt hours a year. According to the company, that’s enough electricity to power approximately 23,000 homes. Based on an internal study, Wal-Mart has concluded that it uses 25% to 35% less electricity than its competitors. Numerous other companies have followed suit, including Maine’s Hannaford, whose new Augusta store makes extensive use of daylighting and recently achieved LEED platinum status — the highest rating from the U.S. Green Building Council.
Common concerns associated with replacing artificial light with daylight are glare, insufficient illumination, heat loss, and solar heat gain (warming of the interior through sunlight). All of these issues can be addressed by tailoring a daylighting solution to the specific needs of a business and selecting high-performance products. In Maine, for example, solar heat gain is less of a concern than it would be in Florida, where cooling costs far exceed those for heating.
With the focus on green building and daylighting as an important component, the industry has made great progress with technological advancements such as the Lumira™ Aerogel skylight (formerly Nanogel® Aerogel), which provides an insulating value almost equal to that of an exterior wall without a significant reduction in light transmission. Lumira™ Aerogel-enhanced skylights are up to six times as energy efficient as conventional units and provide an abundance of glare-free, full spectrum diffused light.
Less tangible, though no less important, benefits of daylighting include its impact on worker productivity and health. Studies have found a direct correlation between exposure to daylight and mental alertness, productivity, psychological well being and even physical health. As we move deeper into the digital age, spending a disproportionate amount of time in front of computer screens, finding ways to reconnect us to the natural environment grows increasingly more important.
And finally, complementing electric lights with daylighting reduces a company’s impact on the environment. In the state of Maine, about half of all electricity is produced by burning natural gas. Although as a fossil fuel natural gas is considered to be cleaner than coal or oil, it still has a significant impact on the generation of greenhouses gas emissions. Methane, the principal component in natural gas, is 21 times more powerful as a greenhouse gas than carbon dioxide. The U.S. Energy Information Administration cites Maine as the only New England state where industry is the leading energy consuming sector. Strategies such as daylighting that help reduce electrical demand could help put Maine on a path towards a more sustainable economy, while providing direct benefits to the companies who lead the way.