Namely this:
… those ubiquitous red or green illuminated signs that direct our escape from a building should the need arise? They can’t use very much energy, can they?
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.
There are options like photoluminescent signs, but most codes prohibit them or require fluorescent lights – the equivalent of resident associations prohibiting clotheslines.
A solid if incremental reduction is to switch the light source to LED’s, but this requires investment by the building owner. This owner faces competing demands for scarce capital, and won’t likely see exit signs rise to the top of the priority list.
It is hard enough to get building owners to update vastly larger energy consuming equipment like heating and air conditioning (HVAC) and domestic hot water plants, even though these paybacks can be quite attractive.
According to Natural Resources Canada “… The energy efficiency of Exit Signs are now regulated in Canada and LED technology is the only one able to meet these performance levels.”
Green running man has been spotted at Bentall Centre. http://www.slate.com/articles/life/signs/2010/03/the_big_red_word_vs_the_little_green_man.html
Escalators in Europe default to ‘slow’ when unoccupied; hotel hallways lit by motion activated lights. 6 cents a kwH is bargain http://en.wikipedia.org/wiki/Electricity_pricing#Global_electricity_price_comparison
The main motivation for building owners to replace incandescent exit signs is not the energy consumption, but rather the labour required to monitor and replace burnt out bulbs.