LEDs (or light-emitting diodes)are small sources of light that work when the movement from electrons illuminate semiconductor material. this longer lasting technology is usually found in traffic lights and exit signs, but now consumers can find options like LED light bulbs and even Christmas light. companies like GE are working to make LED technology more affordable and practical for homes. the department of energy estimates that rapid adoption of LED lighting in the U.S. over the next 20 years can reduce lighting electricity demand by 33% by 2027.