LED high-bay lighting has many advantages besides energy efficiency, including reduced maintenance, long life, controllability and directional control of the light. (Photo by Digital Lumens)
Technology spotlight: LED lighting, controls save energy in high-bay warehouses
After years of product evolution, LED lights are now powerful enough to be used in high-bay mounts—industrial lighting fixtures located high above the floor or work station.
Costs for LED systems are dropping while the quality and variety of LED products has continued to improve. As a result, LEDs are rapidly becoming the preferred technology for new and retrofitted lighting applications, especially in facilities like warehouses that must comply with energy code requirements specifying more controls and lower power allowances (e.g., ASHRAE 90.1-2010).
High bar for efficiency
In many high-bay spaces, high-performance fluorescent systems are the standard of efficient lighting. They provide high-quality, white light, maintain high lumen output over years of use, have increasingly long lamp life and can be controlled through occupancy or daylight sensors.
Older warehouse lighting often consists of 250- to 1,000-watt high-intensity discharge (HID) lighting that operates for long hours, regardless of actual occupancy, because HID lighting does not respond well or quickly to frequent switching.
Ready to compete
LED systems save money by providing high-quality light even though less measurable light is produced – and less energy is used – than with fluorescent lighting systems.
- Highly directional LEDs produce less stray light and tighter distribution patterns, so all of the light goes where it is needed.
- The bluish white light improves visual acuity.
Challenges of replacement
Unlike compact fluorescent lights (CFLs), there is no per-wattage basis for replacing HIDs with LEDs. Installing more or higher-wattage LED lamps does not necessarily result in more useful light. The light output and energy use are determined by the type and combination of LEDs and their drivers—the self-contained power supply with outputs matched to the electrical characteristics of the light.
Newer LED products are generally more efficient and less expensive than older models. Manufacturers often include “equivalent to X watt HID” notes to help buyers choose which LEDs to replace their traditional lamps. Three LED products marketed to replace a 1,000-watt metal halide warehouse lamp (78,000 lumens) have these values:
- 259 watt – 26,663 lumens
- 315 watt – 26,000 lumens
- 344 watt – 34,000 lumens
Costs for these products range from $1,000 to $2,000 per luminaire, and some include integral controls. Also, you need to consider color temperature and distribution patterns when selecting an LED product to replace traditional lighting.
Stellar energy savings
A review of LED technology by the Bonneville Power Administration (BPA) Energy Efficiency Emerging Technologies (E3T) program found average energy savings of 50 to 90 percent over existing technologies, depending on what equipment is replaced and what controls are installed.
For example, when a 180-watt LED fixture replaces a 400-watt high-pressure sodium (HPS) fixture, controls can be applied to the LED fixture to boost energy savings higher than 90 percent. For more information, see the LED High-Bay with Wireless Control fact sheet.
High-performance fluorescents are hard to beat for energy efficiency and economics, but in some applications, the unique qualities of LEDs make them desirable for reasons beyond energy efficiency. LEDs:
- Contain no mercury, making them safer and easier to dispose.
- Are very durable and resistant to vibration.
- Improve light output in cold temperatures, where fluorescent performance declines.
- Can be designed to operate in fairly high ambient temperatures.
- Can be switched over very short periods – seconds, rather than the 15 minutes fluorescents need to preserve lamp life and warranties. This means LEDs work better with energy-saving occupancy sensors.
- Can be dimmed without degrading efficiency or lamp life, to work with daylight harvesting.
- Work well with digital controls and wireless systems for fast and easy installation.
- Often come with sensors and controls that can be programmed from a computer so they can easily be reconfigured. The software also provides energy use data needed for incentive programs or resource management.
- Contribute much less heat into a space, reducing cooling loads.
- Substantially reduce maintenance costs due to their long life.
- Do not fail suddenly. Over time, LEDs slowly fade so replacement can be anticipated and scheduled.
Before you buy
Before investing in LEDs:
- Consider adding controls if you currently have a high-performance but uncontrolled fluorescent system with intermittent occupancy.
- Make sure your contractor is qualified to install LEDs and use control systems.
- Install two or three of the LEDs you are most interested in and see how they perform in your application before placing a large purchase order.
- Review up-to-date information before committing to a large-scale purchase because LED technology is rapidly evolving.
- Consult with your utility about incentives or contact Western’s Energy Experts hotline for additional assistance at 800-769-3756.
See the following resources for more information about performance-tested LED products: