Facilities with ceilings higher than 25 feet—such as big-box stores, school gymnasiums, sports venues, warehouses, and manufacturing plants—use high-bay lighting.
Although high-intensity discharge (HID) and fluorescent lighting still dominate the high-bay lighting market, LEDs have become more popular due to their technological improvements. LEDs can be cost-effective because of their longer lamp life; long operating hours lead to higher energy and maintenance savings. High-bay environments often provide opportunities to control light levels based on occupancy and strategic use of daylight. Although previous LED products didn’t provide enough light for most high-bay applications, some of the latest products can replace metal halide lamps up to 1,000 watts.
What are the options?
The lamp type you choose—and any controls you add—can save energy and money.
In the past, if you wanted to upgrade a facility that had old probe-start metal halide lamps, your options included fluorescent lamps (both older low-performance and newer high-performance), HID lamps, and ceramic metal halide lamps. Now you can choose LEDs for nearly every lighting application, including high-bay lighting.
High-bay LEDs come in rectangular and circular fixtures and are great replacements for high-performance fluorescent lamps and older HID lamps. As their costs have decreased, LEDs have surpassed fluorescents by offering:
- Comparable (or higher) efficacy
- Longer life
- Similar color quality
- Better controllability
- Increased flexibility with light distribution patterns
A large high-bay site might have the lights on across the entire facility, even if only a small portion is occupied at any given time. In these cases, the ability to turn lights on when they’re needed and off when they’re not can save a a lot of energy. Occupancy sensors and timers can increase savings, but you need to combine them with lighting systems that work well with controls.
HID light sources have long startup and restrike times, so they’re not well suited to controls-based occupancy. But you can dim them to about 50% of initial power. Fluorescent lighting is a better choice for controllability due to its faster startup time, but frequent on-off switching can reduce the lamp’s life span. LEDs are the easiest to control—they react instantly, and constant switching doesn’t decrease their life.
For some facilities, skylights and daylighting controls, which modulate electric light levels based on available daylight, can also save a lot of energy. In addition, lighting-control systems can automatically turn lights on and off based on a preset schedule, rather than relying on personnel to remember to turn lights off.
How to make the best choice
LEDs have the potential for the highest efficiency and lowest life-cycle costs of the high-bay lighting alternatives (figure 1). LED fixtures are available in a wide price range, and, with LED prices falling at a rapid rate, the cost of LEDs over their lifetime will shrink even more. Because cost and performance vary, be sure to evaluate the technology with the correct data for your application.
Figure 1: LEDs cut life-cycle costs for high-bay lighting
|Metric||Baseline: Probe-start metal halide||Ceramic metal halide with electronic ballast||Six-lamp T8 fluorescent||LED||LED with controls|
|Notes: kWh = kilowatt-hours; lm = lumens; NA = not applicable; W = watts. Assuming operation of 5,000 hours per year with an electricity cost of $0.10 per kilowatt-hour. The case for LEDs with controls assumes 50% energy savings from turning lights off when areas are unoccupied.||© E Source; data from manufacturers|
|Initial lamp output (lm/lamp)||36,000||25,000||3,100||13,000||13,000|
|Design lumens (40% of lamp life)||24,000||20,000||2,915||11,400||11,400|
|Lamp life (hours)||20,000||24,000||60,000||100,000||100,000|
|Fixture input power (W) (lamp and ballast)||465||221||212||155||155|
|Fixture efficiency (%)||70||90||90||100||100|
|Design output from fixture (lm)||16,800||18,000||15,741||11,400||11,400|
|Color rendering index||65||90||80||80||80|
|Electricity used (kWh/year)||2,325.0||1,105.0||1,060.0||775.0||387.5|
|Electricity cost ($/year)||232.50||110.50||106.00||77.50||38.75|
|Fixture installed cost ($)||NA||300.00||185.00||600.00||650.00|
|Maintenance cost ($/year)||20.00||25.00||10.00||5.00||5.00|
|Annual savings ($/year)||NA||127.00||136.50||170.00||208.75|
|Life-cycle costs ($ over 10 years)||2,525.00||1,355.00||1,160.00||825.00||437.50|
There are a few attributes you should keep in mind when evaluating LEDs for high-bay use.
Lifespan and light qualities LEDs have a longer life than HIDs and most fluorescent products. LEDs also have similar color quality, more controllability, and the potential for better light distribution patterns. You can waste less light on areas that don’t need it (such as the top of a storage rack) and provide more-even light distribution where you want it (such as on the objects that are in the storage rack). LEDs help you meet required light levels with fewer total lumens.
Occupancy sensors LEDs do well with on-off occupancy sensors because frequent cycling doesn’t shorten their life like it does with fluorescent lamps. And, unlike HID lighting, LEDs don’t have a long warmup or restrike time.
Dimming Dimming can improve LED efficiency and increase lamp life. Fluorescent lamps lose efficiency when dimmed, and metal halide lights can shift color when you dim them below about 50% of full output. Keep in mind that some LED products also shift color when you dim them.
Dirt and pollution Many high-bay LED fixtures have a horizontal top surface that accumulates dirt, which can reduce the fixture’s ability to keep the lamps cool. Fixtures with vertical fins are less prone to clogging from dirt accumulation.
Air temperature Because LED performance improves in colder conditions, the most promising early high-bay installations of LEDs were in cold storage facilities. Since then, LED products have become more efficient, and high-bay installations have expanded to general warehousing applications. You should compare a fixture’s rated temperature to the expected ambient conditions.
Sensitive materials LEDs emit little infrared or ultraviolet radiation, so materials like food or fabrics have a longer shelf life. Additionally, LEDs contain no mercury—a plus in a food-handling environment—and could reduce end-of-life disposal costs for the lamps.
The DesignLights Consortium (DLC) has a searchable Solid-State Lighting Qualified Products List where you can find products that the DLC has certified meet minimum standards. For a product to be on the list, it must meet requirements such as:
- Lumen maintenance (which determines lamp life)
- Minimum light output
- Minimum fixture warranty
- Light distribution
- Color rendering index
- Color temperature
See the DLC’s Technical Requirements to find specific requirements for different application types. The requirements are set to equal or exceed the performance of the best of the fluorescent or HID products.
What’s on the horizon?
LED lighting continues to improve in performance and decrease in cost and has become cost-effective in many applications. The US Department of Energy study Adoption of Light-Emitting Diodes in Common Lighting Applications (PDF) found that prices for high-bay lamps and lights dropped by 80% between 2012 and 2016. The average efficacy of LED high-bay lamps in 2016 was 103 lumens per watt. A growing number of products also incorporate wireless networked sensors and controls that reduce energy use and perform proactive maintenance. Since market adoption is just 10%, the demand for LED high-bay lighting will continue to grow.
Who are the manufacturers?
Here are just a few manufacturers that offer high-bay fixtures for a variety of light sources:
- 1st Source Lighting
- Eaton’s Cooper Lighting
- GE Lighting
- Lithonia Lighting (an Acuity Brands brand)
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