The research team of Vietch, Stokkermans, and Newsham also has confirmed a significant correlation between positive lighting appraisal by employees in a space, and overall workplace satisfaction and engagement. Quantifying the relationship between daylight harvesting and productivity has proven to be an elusive goal, but new studies show that strong correlations exist.Īs noted in Greenlight New York’s Let There be Daylight: “Because the cost of employees far outweighs all other business expenses, even mild increases in productivity … can have positive financial impacts that dwarf the typical return on investment (ROI) considerations of energy conservation measures.” worker productivity through greater access to sunlight in office buildings.” In its recently published Intersections: Health and the Built Environment, the Urban Land Institute reports a “15% potential increase in U.S. These benefits work to improve mood, memory, and mental acuity, contributing to more productive buildings and building occupants-and like energy-saving benefits, they improve the bottom line. In addition to energy-saving benefits, proper daylight design is widely acknowledged to contribute human benefits: reduced eyestrain, comfort enhancement through increased views, and circadian rhythm entrainment. Savings were based on energy simulation of a perimeter private office with a lighting power density of 0.9 W/ft, a standard clear double-pane glass, and a shade fabric with 5% transmittance and a 76% reflectance. The study showed that perimeter private offices with daylight harvesting strategies in place can further reduce lighting energy usage by 65% through the use of automated shades. Because automated shades respond to real daylight conditions, they can extend the useful daylight zone to 20 ft inside the perimeter, allowing for more effective daylight control.Ī study conducted by Purdue University and Lutron Electronics analyzed the benefits and energy-saving potential of solar adaptive, automated shading control systems. Manual shades can generally achieve a useful daylight zone of 10 ft inside the perimeter windows. As related to energy use, automated shading control works to maintain a consistent light level in all environments, and can extend the useful daylight zone (the area inside a space where enough glare-free daylight is available for daylight harvesting) inside the perimeter of the space. Keep in mind that it is important to choose a shade manufacturer that offers a broad selection of fabrics, allowing the lighting designer or architect to choose the appropriate transmittance level based on the building’s location and orientation.īy using the same lighting control system for daylight harvesting, the electric light can be used only to supplement available daylight, minimizing or eliminating lighting energy use whenever possible.Īutomated shading allows the lighting system to respond to environmental factors related to both energy use and glare. The best solutions combine automated shade control with solar-adaptive software, and cloudy-day/shadow sensors that allow the shading software to evaluate and respond to real-time daylight conditions. 18, 2013, all state commercial building codes must meet or exceed ASHRAE Standard 90.1-2010 that generally include mandatory requirements for daylight harvesting technology known as “Daylight Zone Control.” Other allowable building standards, such as the International Energy Conservation Code (IECC) and California Title 24, include similar daylighting requirements in their updated recommendations.Ī total light management system that includes automated shade control is the ideal lighting design strategy for addressing both energy and glare management. Standards and guidelines developed by ASHRAE are now mandated by the Dept. As utilities struggle to meet increasing demand for power, federal and state agencies are stepping in to regulate energy use. One of the most powerful motivators driving daylight design in new construction and major renovation is code compliance. Lighting control strategies, and daylight harvesting in particular, have a variety of efficiency benefits including: reducing lighting energy, helping to minimize peak demand, and helping to reduce HVAC loads.
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