Big energy savings anticipated from fluorescent light swap

A handful of students will walk through some 50 buildings on campus this summer and fall, counting lights. That count is the first step in a multiyear light replacement project that eventually may yield $300,000 in energy savings annually.

Specifically, the students will tally the number of T12 fluorescent lights in university buildings. Bob Currie, director of facilities, said the university will systematically replace all T12 lights with their bright energy-efficient cousins -- T8 lights -- over the next few years.

Lights out for T12

For decades, T12 lights have been a staple in buildings all over the world. But the lights are inefficient by today's energy standards, and their days are numbered.  The U.S. Department of Energy mandated that manufacturers stop producing T12 lights as of July 2012.

What's on your ceiling?

Energy-efficient T8 lights are a skinnier version of the older, less-efficient T12s. Both are long tubes, but the diameter of a T12 (1.5 inch) is similar to that of an old silver dollar. For the T8, think quarter-sized diameter (1 inch).

Iowa State has enough T12 replacements to light classrooms and offices over the next few years, Currie said.  However, the energy savings from swapping out the old T12s provides plenty of incentive to make the switch at Iowa State as soon as it's financially feasible.

"T8s use 35 percent less energy," Currie said, "and that's a conservative estimate. If Iowa State were to replace all of its estimated 30,000 T12 fixtures and 60,000 lights, the energy savings would add up to about $300,000 a year."

It's unlikely the university can retire all inefficient lights in a short time. Currie estimates that replacing all T12 fixtures with new T8 fixtures could cost up to $10 million. However, facilities staff have been and will continue to chip away at the massive project.

The focus is on buildings built before the eighties, all of which were equipped with T12 fixtures. Facilities that were constructed or renovated over the last three decades should have the T8 fixtures. Of the 100 most heavily used buildings on campus, approximately half already have the more efficient T8s, Currie said,

With a $200,000 allocation this year to the lighting project, facilities staff will convert a number of buildings across campus to efficient lighting. Additionally, FPM staff will continue to make spot light replacements in offices when, for example, a T12 fixture loses a ballast. T12 fixtures that need a fix generally get upgraded to T8 status.

LEDs on the horizon

The big emphasis is on installing T8 lighting, but LED lights also are getting a test run in a few places around campus.

Commonly used for traffic signals, LED lights have moved indoors in recent years and are yielding energy savings of 50 to 85 percent over the old T12 lights, Currie said.

A couple of barriers to widespread indoor use of LED lights exist, Currie said.  The LEDs are expensive, although recent analyses indicate the lights may yield a competitive payback  in some instances.

Another question mark is how people will like living and working under LED lights.

"We don't yet know about LEDs," Currie said. "They look the same as other fluorescents, but there haven't been any real long-term trials."

A couple of trials are under way at Iowa State, he said. LED lighting has been installed in several places on campus, including new classrooms in Physics Hall and hallways in the General Services Building.