Late Night Lighting at the Library

People frequently wonder why the lights at the library are still on hours after it closes. I recently met with the director and then with the building manager to explore various ways to reduce energy consumption. Though it's important to make sure that any new buildings built in town are as energy efficient as possible, the community's greenhouse gas emissions will only go down substantially through improvements in existing buildings. 

The library, particularly as host of the Princeton Environmental Film Festival, has been a leader in programming aimed at educating the community about the dangers of climate change and the actions people can take to reduce our impact. I'm interested in seeing if and how the library could add another dimension of education by reducing energy use while still providing its great service to thousands of patrons every day.

Turns out things get complicated pretty quickly when seeking to make changes, but here's what I learned about lights after hours:

Custodians clean the library after hours. The aim is to begin on the third floor and work down, turning off each floor's lights as they go. If all is going according to schedule, the library closes at 9pm, the top floor gets cleaned and lights go off around 10:30pm, the 2nd floor at 11:30pm, and then the 1st floor an hour after that. The building manager can check video the next day to see when the lights went out. Given language barriers and turnover among workers, it's an ongoing struggle to get custodians to stick to this protocol.

One approach to reducing the lighting needed after hours would be to have the custodians only have one floor's lights on at a time, i.e. turn off floors 1 and 2 before cleaning floor 3, then turn floor 2 back on for cleaning, and so on. I've heard that an approach similar to this was used at Princeton High School, at least for awhile, with considerable success. But as with issues like recycling, it's always a question of training, motivation and sustained followup.