There are an estimated 1.5 million conventional recessed fluorescent fixtures just in the federally owned buildings in GSA’s portfolio, that agency has said, leaving the potential for significant energy and cost reductions for tenant agencies.

Interior lighting accounts for about a quarter of the electricity used in those buildings and there is a potential for cutting those costs in half, GSA said in a blog touting its Green Proving Ground program, which evaluates innovative technologies that have the potential to substantially improve the environmental performance of federal buildings.

It cited the Interior Lighting Campaign program established by the Energy Department as part of its Better Buildings Program to help building owners and managers to take advantage of advances in LED lighting and in control technology—for example, lighting that is responsive to the presence of an occupant or to available natural light.

Lighting in more than 75 percent of GSA’s building stock is controlled only at the circuit level due to the cost and complexity of control wiring and commissioning, GSA said. GSA said there is potential for savings, including retrofitting existing buildings, through wireless-controlled dimming systems and off-the-shelf lighting control systems.