U.S. Department of Energy - Energy Efficiency and Renewable Energy

Building Technologies Program

Implementing Spectrally Enhanced Lighting Solutions

Photo of the interior of an office building with the top portion of cubicle walls visible. The focus of the image is on the ceiling which has two banks of lights. The bank on the left is the pre-retrofit lamps and the bank on the right is the spectrally enhanced lighting. The spectrally enhanced lighting appears brighter than the pre-retrofit lamps.

Pre-retrofit lamps (the left bank of lights in the photo) have a correlated color temperature (CCT) of 3500 kelvin (K) and color rendering index (CRI) of 75. The spectrally enhanced lighting (the right bank of lights in the photo) has a CCT of 5000K and CRI of 82. The higher brightness of these lamps offsets the reduced lumen output. As a result, the lighting appears the same or brighter, using less energy.

On this page, you will learn more about specific lighting solutions and find links to additional information regarding the design method for spectrally enhanced lighting (SEL) and the resulting energy savings.

SEL is market-ready, simple to implement, and can currently be employed in buildings as a cost effective way to get quick energy savings. It is non-proprietary, requires no fancy controls or gadgets, and the energy savings are significant. In addition, SEL is low risk. There are no known negatives to installing this type of lighting in commercial buildings.

Appropriate lamps are available through many major lamp manufacturers and are generally no more expensive than traditional lamps. The predominant light source used in commercial applications is fluorescent lighting; the lamps and ballasts used dictate the efficiency of fluorescent lighting systems. Using higher color temperature fluorescent lighting and new high-efficiency ballasts can achieve energy savings of 20-40% compared to traditional fluorescent lighting systems, according to results of the DOE study, Spectrally Enhanced Lighting Program Implementation for Energy Savings, Field Evaluation (August 2006). These savings can be achieved by simple lamp/ballast retrofits.

A number of forward-thinking municipalities have adopted SEL strategies as standard for all new construction and retrofits, including the cities of San Diego and Oakland and the counties of Napa and San Mateo. Read case studies on SEL installations at:

Discover more about the design method for SEL and how much you can save by viewing the following:

Design Method
Potential Energy Savings
Potential Payback