Solar control and productivity

Photo courtesy Draper Inc.

By Terry Coffey
Solar control solutions are important in helping increase worker productivity. To understand how, one must understand what makes a productive building, and why productivity should be a consideration in design.

Shading systems have traditionally been presented as a way to achieve energy cost savings by using natural light and solar heat gain control to lower utility bills and reduce the size of HVAC and lighting systems. However, by far the biggest amount of money spent annually on a commercial operation is not energy-related, but people-related. Wages and other workforce costs comprise the biggest chunk of operating expense; in this area, shading solutions can also have an impact.

According to the “Productive” section of the National Institute of Building Sciences’ (NIBS’) Whole Building Design Guide (WBDG), typical total life cycle costs of private-sector buildings are:

  • $2150/m2 ($200/sf) per year for salaries;
  • $215/m2 ($20/sf) per year for amortized bricks/mortar cost; and
  • $21.50/m2 ($2/sf) per year for energy.

Based on those numbers, even a very small improvement in productivity can have a huge impact.

WBDG puts forward five basic principles that are part of “productive building designs.” They are:

  • promote health and well-being;
  • design for the changing workplace;
  • integrate technological tools;
  • ensure reliable systems and spaces; and
  • promote comfortable environments.

(For more on these principles, visit the Whole Building Design Guide by the National Institute of Building Sciences [NIBS] at

In addition to those five principles, the WBDG has this to say:

Buildings can be more effective, exciting places to work, learn, and live by encouraging adaptability, improving comfort, supporting sense of community, and by providing connections to the natural environment, natural light, and view.

Based on these factors, window shades and other solar control solutions can have an impact on improved productivity as part of an overall daylighting strategy.

The proper shade fabric can help reduce glare and heat gain while allowing views to the outdoors. Additionally, daylighting and natural views contribute to increased productivity, rather than providing distractions.
Photos © Kenneth Hayden. Photos courtesy Draper Inc.

The case for natural light
People need natural light to create enzymes and proteins for a healthy life. Without enough natural light, the body’s circadian system can no longer properly regulate things like sleep, alertness, and concentration. According to an article from 2000 in the Journal of Occupational Rehabilitation, lack of sleep makes it more difficult to make decisions (This information comes from S.J. Linton and I. Bryngelsson’s 2000 article, “Insomnia and Its Relationship to Work and Health in a Working-age Population,” in the Journal of Occupational Rehabilitation 10[2], 169-183.), and a 1995 Journal of General Internal Medicine report links insomnia to poor job performance. (The report, “Sleep Problems and Their Correlates in a Working Population,” was written by authors M. Kuppermann, D.P. Lubeck, P.D. Mazonson, D.L. Patrick, A.L. Stewart, D.P. Buesching, and S.K. Fifer for the Journal of General Internal Medicine 10, pp. 25–32.) Further, a 2009 CÉGEP  Champlain-St. Lawrence study in in Sainte-Foy, Qué., found insomnia costs the Canadian economy $20 billion per year. (For more on the study, read Andre Picard’s “Insomnia Costing Economy $20 Billion a Year,” published in The Globe and Mail on January 1, 2009. Visit

The key is natural light, which cannot be replaced just by having an effective electric lighting system. Another 1994 study showed there was a statistically significant improvement in job performance in offices with windows. (The study in question was A. Hedge’s “Reactions of Computer Users to Three Different Lighting Systems in Windowed and Windowless Offices,” in Work and Display Units, 94, B54-B56.) The Center for Building Performance and Diagnostics at Pennsylvania’s Carnegie Mellon University looked at the impact of daylighting on productivity and recorded 40 per cent gains when daylighting was introduced into offices. (This is so according to “High-performance Buildings Enhance Workers Effectiveness and Productivity Through Improved Health, Communication, and Comfort” by the Center for Building Performance and Diagnostics.)

Evidence also suggests workers make fewer mistakes in environments with plenty of natural light. One 2003 study of pharmacists found a 3.5 to 2.6 per cent decrease in dispensing errors occurred when light levels were increased from 450 lux (42 fc) to 1500 lux (139 fc). (The study was P. Boyce, C. Hunter, and O. Howlett’s “The Benefits of Daylight Through Windows,” provided from Troy [NY]: Lighting Research Center.) Thus, natural light—and the means of getting it into a building—should be an essential part of designing a building for maximum productivity.

There is more to it than just the light itself, however. Access to window views to the outside also gives workers a connection to nature, which has been found to have an impact on mood, satisfaction, and performance. Another 2003 study showed the mood of daytime workers was significantly better than nighttime workers in the same office with windows. (This information is from U. Dasgupta’s “The Impact of Windows on Mood and the Performance of Judgmental Tasks, M.S. in Lighting thesis,” from Rensselaer Polytechnic Institute.)

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