“Each one uses relatively little electricity, but they are on all the time. And we have a lot of them in our schools, factories, and office buildings. The U.S. Environmental Protection Agency estimates that there are more than 100 million exit signs in use today in the U.S., consuming 30–35 billion kilowatt-hours (kWh) of electricity annually.
That’s the output of five or six 1,000 MW power plants, and it costs us $2-3 billion per year. Individual buildings may have thousands of exit signs in operation.”