A "green" building is one that uses alternative energy and energy-saving technologies to supply all or part of its energy needs.
When the North Adams Public Library's home, the Houghton Memorial Building, underwent renovation and expansion in 2003 - 2005, the design incorporated numerous technologies which qualified it as a "Green Building." These include geothermal wells to heat and cool the building, and solar panels (photovoltaic cells) to convert sunlight into electricity to help run the geothermal pumps. Plans also called for energy-saving lighting, insulation, windows, and environmentally-friendly materials. During construction, much of the wood and other materials removed were recycled, either by reusing them in the building or by passing them on to others who could reuse them.
For example, a local artist Daniel Field acquired pieces of the flaking brownstone foundation and turned them into several working miniature stone fireplaces. He donated five of the fireplaces back to the library for use in fundraising.