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Analyzing Daylighting Designs
The seeming complexities that have caused many architects to shy away from "daylight" designs have given rise to a number of new software programs like SkyCalc, whose development was funded by California's two largest utilities in partnership with the Northwest Energy Alliance. The free tool helps analyze energy impacts of varying designs to determine an "optimum" strategy for maximum lighting and HVAC energy savings.

Lumen Micro, an MS Windows-based program by Boulder-Colo.-based Lighting Technologies permits daylighting analysis based on latitude, longitude, time of day and date and allows users to adjust transmittance and reflectance of windows and skylights and compare the results.

A number of programs that enable users to evaluate thermal and optical performance of window systems are available from the Lawrence Berkeley National Laboratory. They include the "Radiance" lighting simulation and rendering software for Windows. Radiance is a suite of programs for the analysis and visualization of lighting in design. Input files specify the scene geometry, materials, luminaires, time, date and sky conditions (for daylight calculations). Calculated values include spectral radiance (ie. luminance + color), irradiance (illuminance + color) and glare indices. Simulation results may be displayed as color images, numerical values and contour plots.

The primary advantage of Radiance over simpler lighting calculation and rendering tools is that there are no limitations on the geometry or the materials that may be simulated. Radiance is used by architects and engineers to predict illumination, visual quality and appearance of innovative design spaces, and by researchers to evaluate new lighting and daylighting technologies.

SUPERLITE 2.0 is a powerful lighting analysis program designed to accurately predict interior illuminance in complex building spaces due to daylight and electric lighting systems. SUPERLITE enables a user to model interior daylight levels for any sun and sky condition in spaces having windows, skylights or other standard fenestration systems. SUPERLITE is a DOS-based program that runs on IBM-compatible personal computers under the MS-DOS operating system.

EQuest, an inexpensive add-on to building energy analysis program DOE-2, enables detailed analysis of building design performance for those with limited experience in building performance modeling.

Genelux-Web, a simplified version of Genelux-R, allows designers to compare daylight penetration from various openings, estimate obstructions from overhangs, evaluate various finishes and otherwise evaluate the daylighting performance of buildings directly on the Internet.