The results are in and Central Library is doing even better than expected in terms of sustainability efforts.

Central was tapped three years ago by the Arlington Initiative to Rethink Energy to be the County’s first showcase project for the U.S. Department of Energy’s Better Buildings Challenge. The goal was to cut energy use 20 percent by 2020, with 2008 data as the baseline.

So far, thanks to a healthy array of solar panels up on the roof and a long-awaited chiller replacement, Central Library is saving 28 percent annually in energy.

That translates to $56,000 a year saved by Arlington County.