Abstract

Daylighting, hailed as a cornerstone of sustainable design of buildings, has the potential to reduce lighting energy which can be 40% or more of the energy cost of a commercial building. We find that daylighting control systems often do not provide the expected energy savings. In the construction industry which is very risk averse, even limited failures can dramatically slow the advance of valid technologies. There are numerous reasons for failure. Natural light sources are complex and vary through the day and year, implementation requires coordination between different building design and construction trades, the documentation and specification of the controls equipment is often inadequate, and calibration after installation is rarely done well and can be confusing and time consuming.

In this paper, we provide eight case studies as representative examples where daylighting systems did not meet expectations and describe how users reacted to different types of failure and how they cope with what appears to be a failed daylighting system. We further propose a method for failure analysis, identify four modes of failure, and provide a template for each mode for easier problem resolution in future. We discuss how decisions are made and documented in the development of daylighting systems in typical commercial buildings. We describe the state of expertise of the trades involved in delivering daylighting systems in commercial buildings.