I had the pleasure of presenting a talk titled “Daylight for Comfort and Profit” at the local United State’s Green Building Council’s (USBGC) Green N Grub presentation last week.  It was located in the Greenwood Village Town Hall Community Room, a good location, as it enabled me to discuss the lost opportunities for daylighting that are present in so many of our public buildings.  We entered the building into a high ceilinged atrium with a central skylight and east/west clerestories which should provide daylighting.  And yet, every electric light was turned on in the midst of a beautiful sunny Colorado fall day.  I asked a Greenwood Village staff member if he know how to turn off the lights or even knew where the light switches were, and he responded that he did not.  Nobody there could recall those lights ever being turned off.

The essence of the talk was that daylighting can be used to simultaneously improve life for occupants of such buildings while reducing energy cost.  Research now demonstrates that the benefits of daylighting extend to a wide variety of building types, including office, retail, health care, and education. Interestingly, the research also demonstrates that poorly implemented daylighting has a detrimental effect.  Successful daylighting depends on mastering a large number of critical details, so that glare and excessive contrast ratios are avoided, while providing useful ambient light.

Because electric lighting can consume as much as 25% of total electricity use, 40% of total energy cost, and contribute as much as 47% of greenhouse gas, it is a logical place to look for savings.   In our building projects, we assume we can cut that electric light bill in half, and sometimes even more, saving our clients substantial amounts of operating cost if the electric lights are off.  And that is where most daylighted buildings fail, just as in our host building.  Getting the lights turned off when daylighting is adequate is the greatest challenge we face as daylight designers.  And in order for that to happen, a good understanding of the emerging field of Human Factors is helpful.  But that’s a topic for another day.

By Paul Hutton