Lead Performer: Pennsylvania State University – University Park, PA
Partner: University of Sydney (Australia)
DOE Total Funding: $361,231
Project Term: October 1, 2021 – March 31, 2025

Funding Type: Buildings Energy Efficiency Frontiers & Innovation Technologies (BENEFIT)


The widespread commercialization and adoption of light-emitting diodes (LEDs) have notably reduced the energy consumed by lighting in U.S. buildings. However, there are physical limits to the efficiency with which light can be generated by electricity, so the strategy of improving lighting hardware alone cannot produce energy conservation gains indefinitely. The most widely used measure of lighting energy efficiency, luminous efficacy, quantifies the intensity of light generated by light sources, weighted by the spectral sensitivity of the human visual system. While luminous efficacy provides lighting manufacturers and designers with an accurate and useful metric for quantifying the energy efficiency of individual lighting devices, it does not fully address the use of lighting in architectural spaces.

Researchers quantify changes in energy consumption when they investigate different methods to illuminate architectural spaces, but currently there is no practicable way for lighting practitioners to characterize the overall efficiency of a lighting system. Lighting application efficacy (LAE), the relationship between the electrical power consumed by lighting hardware and the amount of light that contributes to the visual perception of building occupants, must be measured to examine the performance of lighting design solutions in application. To address this need, Pennsylvania State University will develop an application-agnostic LAE framework for indoor environments. The project’s primary outputs are a method for measuring LAE and a framework for facilitating future research to improve the metric going forward. A spreadsheet tool will be developed for lighting professionals that will use the outputs of lighting design software to calculate LAE.


Pennsylvania State University’s LAE framework will enable the holistic evaluation of building lighting systems rather than individual luminaires. The lighting community will be able to develop innovative new strategies for balancing conflicting lighting goals and requirements with the help of the proposed application efficacy metric. The ability to measure application efficacy will also drive the adoption of more energy-efficient design practices, foster product innovation, and, ultimately, reduce the energy consumed by lighting.


DOE Technology Manager: Wyatt Merrill, wyatt.merrill@ee.doe.gov     
Lead Performer: Dorukalp Durmus, Pennsylvania State University

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