Building 33 is located in the historic Washington, D.C., Navy Yard, and its construction dates back to 1850. Originally a 45-foot-high, open-bay factory building, the facility, along with a linked building cluster, underwent a substantial renovation. The building's primary function is to house the general offices of the Naval Facilities Engineering Command. The project's reuse of a brownfield site and reuse of an existing building were its most prominent green features. Energy efficiency was a high priority, and it was accomplished by improving the thermal envelope and by reducing electricity consumption. Generous amounts of insulation were added to the new, internally applied ceiling and wall assemblies, and insulated glass panels were installed on the interior of existing windows. Daylighting and task lighting were used to reduce the amount of ambient lighting needed, and occupancy sensors and automatic dimming controls further contribute to overall lighting efficiency. Recycled content materials were used throughout, and some materials were salvaged from the site and reused.