Daylight harvesting combines integrated lighting control systems with the oldest energy source around – the sun.

and according to Lutron figures, facilities can save as much as 70 percent on their lighting expenses through daylight harvesting and other energy-saving strategies such as occupancy/vacancy sensors, appliance control and scheduling. Matthews says that there is a 1:1 percentage ratio of light dimming to energy retention, meaning that if a light is dimmed 10 percent it uses 10 percent less energy. Most older facilities are overlit, running internal light systems that produce more light than is needed and operate only at full-tilt, says Matthews. So one of Lutron’s energy saving strategies is high-end trim – simply dimming lights in such facilities by 20 or even 30 percent.

Estimates on the time it takes to see a return on investment on daylight harvesting lighting control systems vary. Meshberg conservatively estimates that it takes three to five years to see a return on total control lighting systems in new facilities, and four to six years in retrofit projects. The more the total control systems are optimized, the higher the savings. For instance, Meshberg routinely pitches the idea to schools that they can use lighting control systems to dim lights by 30 percent during vacations the same way that HVACs run on minimum output during times that buildings aren’t in use.

“The more strategies that are in play the more your savings are [and] you’re not compounding the amount of hardware to do that,” Meshberg says.

Tied into the cost-saving potential of daylighting and daylight harvesting is worker productivity. There are a lot of studies (here’s one) that conclude that harsh indoor lighting diminishes worker productivity; conversely, adjustable lighting control systems can improve worker productivity. That is because properly diffused light relaxes the human eye, decreasing physical tension in the human body – creating a more relaxed work environment, no matter the setting. This is one of the reasons that daylighting and daylight harvesting are increasingly popular, says Grable.

“There’s going to be continued use of daylighting because of the human performance side,” he says. “It’s a proven fact that people perform better when there’s more light… [s]tudents come to school more often, businesses have less absenteeism and yet they have more productivity.”

And because workers are the largest expense for any business, getting greater performance

Commenting is not available in this channel entry.