University of Michigan Study Highlights LED Energy and Cost Savings

In a groundbreaking study by the University of Michigan’s Center for Sustainable Systems, researchers unveiled significant cost and energy savings from transitioning from fluorescent lights to LED lighting in commercial and residential settings. This research, spearheaded by Greg Keoleian, co-director of the Center for Sustainable Systems, underscores the economic and environmental benefits of switching from fluorescent to LED lighting systems.

According to the study, LED lighting is up to 44% more energy-efficient than 4-foot fluorescent tubes. This substantial efficiency gain is crucial given that lighting accounts for 11% of electricity use in commercial buildings and residential basements, garages, and shops. The study’s comprehensive analysis compared the costs and efficiencies of six lighting replacement options, including one fluorescent and five LED alternatives, focusing on linear recessed lighting systems, also known as linear fixtures or troffer lights. These systems represent a significant opportunity for enhancing energy efficiency due to their prolonged operating hours.

The findings revealed that LED products are 18% to 44% more efficient than T8 fluorescent lamps. Keoleian emphasized the advantages of LEDs over fluorescents, stating, “Our finding is consistent with the U.S. Department of Energy’s indication that LED systems are 25% more energy-efficient than fluorescents.” Beyond energy efficiency, LED lamps offer several benefits, including flicker-free illumination, enhanced dimming performance, faster ramp-up to full brightness, and improved durability, leading to reduced maintenance and LED cost savings.

One notable aspect of the study is the detailed comparison of replacement options. These include:

1. Fluorescent Lamp Replacement: The least recommended option due to lower efficiency and cost savings compared to LED alternatives.
2. Plug and Play Type A LED Lamp: This option requires no modification to existing fixtures and is compatible with both electronic and magnetic ballasts.
3. Direct-Wire Type B LED Lamp Retrofit: Involves modifying the fixture to accommodate new light sources, offering the lowest life cycle costs despite higher installation costs.
4. Hybrid Type AB LED Lamp: Works in existing fixtures or with removed ballasts, providing a cost-effective solution when the existing ballast is still operational.
5. LED Luminaire with Replaceable Lamps: Offers a balance between upfront and operational costs, though design options may be limited.
6. LED Luminaire with Integrated Non-Replaceable Lamps: Provides design flexibility at a higher initial cost, resulting in a higher life cycle cost.

The research highlighted that while all LED options bring cost savings over time, the exact savings depend on factors such as lamp costs, electricity rates, and labor expenses for retrofitting or replacing recessed fixtures. For commercial building owners and managers, understanding these trade-offs is essential for making informed decisions about lighting replacements.

Published in the journal Lighting Research and Technology, this study serves as a valuable resource for both commercial and residential applications, particularly in spaces like workshops, basements, and garages, where T8 lamps and troffers are prevalent. The research received support from the National Science Foundation Graduate Research Fellows Program and the University of Michigan Rackham Merit Fellowship, with contributions from Lixi Liu of the Center for Sustainable Systems and the U-M Department of Mechanical Engineering, and Geoff Lewis of the Center for Sustainable Systems.

Click here to read the full article, originally published December 5, 2023 by University of Michigan’s Michigan News.