T-5 Fluorescent Lighting Outshines HIDs

It has long been believed in the design profession that, for indoor settings, fluorescent lighting made the most sense for low ceilings—below about 15 or 20 feet (4.5 m to 6 m)—and high-intensity discharge (HID) lighting was the best choice for higher ceilings (high-bay applications). No longer. New developments with fluorescent lighting, especially high-output T-5 lamps and specially designed high-bay fluorescent fixtures, give fluorescents the upper hand almost without exception.

According to energy consultant Jim Rogers, P.E., of Chelmsford, Massachusetts (who co-authored the recent report “New High-Intensity Fluorescent Lights Outshine Their HID Competitors” for E Source, of Boulder, Colorado), there are now at least 14 fixture manufacturers producing high-bay fixtures for long twin-tube or straight-tube T-5 lamps. (The T-5 designation means that the lamps are 5⁄8” [16 mm] in diameter.) These fixtures pack a lot of these very bright lamps (typically four to eight) into a relatively small luminaire with high-efficiency reflectors that deliver almost all of the light output downward.