Research into use of DayLight could be argued as unnecessary, or unreasonable. It was after all the principal means of lighting buildings until the middle of the 20th century. Adopting ‘old-fashioned’ approaches to design will it is sometimes argued not improve the quality of the indoor environment. However, even during the course of this four year project the need for further research has become more critically obvious. This is not just because there is a significant and growing backlash against late 20th Century electrically lit buildings. If that were the problem then we could return to the (day)lighting design approaches of the late 19th and early 20th Century. Today, however, we have much higher expectations for human health and safety in the workplace, and a far wider range of tasks to light (e.g. a mix of paper and digital tasks).
Two years into this IEA project, an article in Architectural Lighting by James Benya ironically with the same title as the project (Daylighting for the 21st Century) stated: The problem is the modern architect is generally ill-equipped to evaluate the performance of daylighting design. Crucial decisions concerning daylighting are made in the schematic design phase, but most architects have no tools, other than common sense and experience, to measure the final effect. During early schematics, for example, it is hard—or even impossible—to thoroughly compare the ultimate performance of alternative fenestration proposals. Yet this very aspect is often the difference between one LEED level and another, with up to 12 precious LEED points at stake.
"Mainstream practitioners think they are doing daylighting, just because their building has windows. They have such a simple view of daylight that they don't know how to think about it usefully," says Lisa Heschong, architect and principal of the Heschong Mahone Group, a Sacramento-area firm specializing in building science research. This is a theme Lisa returned to during the discussion of her presentation of the HMG work to the April 2005 working meeting hosted by Lawrence Berkeley National Laboratories of this IEA project.
The problems arise because of excessive reliance of these 20th Century buildings on electrical lighting, recent increases in the cost of electricity generation, higher levels of expectation among designers and building occupants with respect to the comfort conditions buildings provide, and the availability of window and daylight control components promising higher performance. In the European Union this problem has been exacerbated by the legislative push of the EU Directive on the Energy Performance of Buildings.
The reality in architectural practice is that too often voluntary and mandatory systems like LEED and the EU Directive compliance tools are ‘rule-of-thumb’ based assessments and they inevitably produce in the typical practitioner’s mind a risky relationship: good daylight equates to bigger windows. Too often bigger windows actually equate to reduced environmental quality not just in lighting but also in temperature and air quality for the individual in his or her office.
In addition, recent research work such as HMG’s studies of Schools, Shopping Centres and Call-centres and has shown clear connections between the quality of work performed in Schools and Workplaces and the quality (note: NOT merely the quantity) of daylight available. Added to this, more and more clients are reading of this work and demanding daylit buildings. “Bigger windows” is the call.
In the face of this increasing risk that more daylight is confused with good daylight there is a need to integrate the work of the architectural and engineering professions and inform this integration with the type of targeted research completed for this project.
Despite the many universities offering technical advice and consultancy services in the specialist area of daylight design, and the wide participation of such faculty in this IEA research project and similar projects, Benya comments that, at least in North America: “Few colleges of architecture have faculty with genuine daylighting expertise; and even fewer have artificial skies, heliodons, and other systems for scale modeling and measuring daylighting performance. There is a tenuous acceptance of computer analysis and an unfortunate scale-modeling-versus-computer-modeling controversy brewing.” A further targeted outcome of the IEA research has been identification of daylight resources of use to educators as well as practitioners, and to identify the areas that could be subject of further research in graduate schools.
Added to this is the availability of a wide range of new daylight technologies including:

• new glazing systems;
• improved responsiveness and programmability of integrated electric lighting controls;
• greater claimed accuracy in lighting design software.

These products allow modern buildings to gather a lot more light than similar buildings have in the past and the software makes lighting performance prediction much more accessible than in the past. However, careful laboratory testing is required to characterize the actual performance of these both the physical products and the software. Reliable performance simulation requires trusted data and trusted design tools. Production of reliable data, trusted design tools and their integration into the design process provided the overall aim of this IEA research project.