The Evolution of Exit Signs (and Why the Latest is a Bad Idea)
October 27, 2006
For starters, tens of millions of exit signs in North America still operate 24/7 with two 20-watt incandescent lamps. Each of these exit signs can use almost as much electricity on an annual basis (350 kilowatt-hours) as the most efficient refrigerator. Nationwide, the U.S. Environmental Protection Agency (EPA) estimates that exit signs in commercial buildings use 30–35 billion kilowatt-hours (kWh) of electricity per year. That’s the output of five or six 1000-MW coal-fired power plants, and it represents an annual cost on the order of $2–3 billion per year.
The evolution of exit sign technologies over the past several decades is a story of new technologies that have dramatically reduced their appetite for energy. Indeed, the most common exit signs sold today, those using LED lighting, use as little as two watts—one-twentieth the electricity consumed by older incandescent models. And some exit signs today don’t use any electricity at all.