Abstract

Daylighting, hailed as a cornerstone of sustainable building design, is the primary passive solar design strategy in commercial buildings. It has the potential to significantly reduce lighting energy, which can be 40% or more of the energy cost of a commercial building. We have found that projects with daylighting often do not provide the expected energy savings. In a risk-averse construction industry, 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 four case studies as representative examples where daylighting did not deliver the expected energy savings. We identify the primary modes of failure and provide a template for each mode for easier problem resolution in the future. Through a detailed analysis of the case studies, we identify problem areas in the design and implementation process; we propose a more generalized solution set for design steps, documentation requirements and implementation checks that increase the chances of success.