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Energy-efficient options for “high-bay” spaces

New fluorescent technologies are becoming the Energy Smart choice for lighting indoor spaces with high ceilings. Along with producing light more efficiently, the latest generation of fluorescent fixtures provides higher quality light and features virtually instant on/off capability compared to High Intensity Discharge (HID) light sources.

Photo: Gary Tarleton The fluorescent fixtures in the Harvest House Publishing warehouse are controlled by sensors that shut them off when the area is not occupied.

For many years, the workhorse for warehouses, industrial facilities and other “high-bay” applications has been HID light sources, such as metal-halide and high-pressure sodium. While HID fixtures continue to be a good choice for outdoor applications, fluorescent systems can lower interior lighting energy consumption by 40 percent or more with no increase in maintenance costs.

“The instant switching capability of fluorescent light sources makes it easier to take advantage of natural light from skylights or to install occupancy sensors in areas with infrequent use,” says EWEB Energy Management Specialist Rod Olsen. “It can also allow occupants to manually turn off lighting when it is not needed.”

For example, a local home improvement store replaced standard metal-halide fixtures using 460 watts each with fluorescent fixtures that use only 230 watts. Energy savings like this add up to significant dollar savings.

In another case, when a local publishing house built a larger facility, a goal was to minimize energy use without compromising the working environment. Occupancy sensors were installed in the aisles of the 62,000 square foot warehouse to extinguish unneeded light, a strategy that helped to promote fluorescent lighting over a traditional HID highbay approach.

Although HID technology has improved in recent years with the introduction of pulse-start metal halide lamps, they still must “warm-up” over a period of minutes to achieve full brightness. When they are turned off, they need time to cool down, and time to warm up again. This “start-up and re-strike time” often means that when HIDs are turned on, they stay on, usually for long periods of time.

HID light output also decreases over time much more than fluorescent sources. Light output can drop as much as 40 percent after the first year. Some of the newer fluorescents lose only five percent of their original light output over the 24,000-hour life of the lamp.

Energy-efficient fluorescent lighting has a higher color quality, which may enhance visual acuity and increase productivity.As with most lighting projects, there are many considerations and options. Along with offering cash incentives and low interest loans, let EWEB work with you to select the option that works best for your facility.

The added cost for the installation of the fluorescent system should be offset by reduced energy consumption, often with a 2-year simple payback or less.