WASHINGTON, June 30 -- The National Association of Home Builders (NAHB) has earned its fifth Energy Star designation for the National Housing Center, the downtown Washington, D.C. office building that serves as the association's headquarters.

The designation recognizes buildings that conserve natural resources while providing a comfortable and healthy environment for employees and visitors.

Since the building was significantly expanded and renovated in 2001, the Housing Center's property manager, Transwestern, has continued to fine-tune the details of the original energy-efficient construction project. Attention to the operation and maintenance of the building is the key to holding the line on energy use and utility costs, said NAHB President and Chief Executive Officer Jerry Howard.

"We believe that it's important to make today's building stock as efficient as possible, and these improvements demonstrate how we put these values into practice," Howard said.

To earn its fifth designation, Transwestern engineers continued to install occupancy sensors in common areas so the lights turn on only when the room is in use. Low-flow aerators were installed in all restroom sinks as well as additional insulation around the perimeter of the building.