Not long ago, it was understood that you could gauge the brightness of an incandescent bulb based on the wattage listed on the box. People knew instinctively how many 60- or 75-watt bulbs were needed to light a living room, and similarly how many 450-watt high-intensity discharge fixtures were needed to light a warehouse. However, watts are not a measurement of brightness, they are a measurement of energy use. As lighting becomes more efficient, brighter lights use fewer watts, which makes the correlation most people relied on for years less and less relevant.
Similarly, the size of fluorescent tubes and fixtures has long been the yardstick for measuring brightness and light distribution. Once again, due to inherent differences between fluorescents and LEDs, asking how big a fixture is won’t adequately answer questions about LEDs except the literal one — How much space will it occupy?
Using outdated concepts to determine which fixture to install is like comparing smartphones and landlines based on their number of buttons. Those who become familiar with the features and cost requirements of LEDs will be better able to decide what type of fixture will help a facility reach its foot candle requirements, energy savings and other goals.
Each warehouse and distribution center has different needs, but the direct, bright light produced by LEDs is uniquely beneficial when compared to older lighting technologies. Below are some common questions about LED upgrades.
Q: What Is An LED Anyway?
LED stands for light-emitting diode. Rather than an electric arc or delicate filament, LEDs create light by passing electrons over a tiny, flat semiconductor. For half a century, LEDs have been used for small indicator lights in consumer electronics like computer keyboards and telephones. Thanks to their low heat production, negligible energy use, long life and durability, they were prized for enclosed devices that aren’t intended to be disassembled. Only in the last decade or so has LED technology advanced to the point where it can efficiently produce bright, white light ideal for room and task lighting.
Q: How Many Bulbs Do LED Fixtures Use, And How Often Do I Have To Replace Them?
None, and never. Unlike traditional bulbs, LEDs don’t abruptly burn out; instead, they slowly dim over a period of years or decades. Life cycles vary, but premier fixtures have an average rated life of 130,000 to 150,000 hours. The average rated life of an LED is the time it takes to reach 70 percent of its initial brightness, so the overall life of the fixture could be much longer. Still, 150,000 hours equates to 17 years if the fixtures are in use for 24 hours a day, which is a long time to go without a bulb change.
Q: If Watts And Size Are Useless, How Do You Measure Brightness?
Lumens are the actual measure of brightness, and they’re slowly becoming the accepted form of expressing the effectiveness of bulbs and fixtures. The Federal Trade Commission started requiring lumen output to be included on the packaging of most lights in 2012. However, to those unfamiliar with the term, it’s a meaningless number. Lumen output varies by make, model and manufacturer, but here are a few average comparisons to help:
- 60-watt incandescent bulb = 800 lumens
- 100-watt incandescent bulb = 1,600 lumens
- Single 48-inch, 32-watt T8 fluorescent bulb = 2,800 lumens
- Four-bulb 48-inch, 32-watt T8 fluorescent fixture = 11,200 lumens
- High-end garage light LED fixture = 13,000 lumens
- High-end high bay LED fixture = 26,000 lumens
Q: If Fluorescent Bulbs And LEDs Have Similar Lumen Output, Why Do Facilities Look So Much Better With LEDs?
The light produced by bulb-based fixtures have 360-degree distribution, so not all light from these fixtures reaches its destination. An LED fixture may produce similar total lumens as other fixtures, but it does so more efficiently, putting more light on the target area and appearing clearer and brighter than conventional bulbs.
Because high-intensity discharge, fluorescent and LED fixtures all distribute light differently, replacing fixtures 1-to-1 is often not the best solution for total light coverage. Lighting companies should completely customize a layout for large spaces like distribution centers.
Q: How Much Energy Can I Save?
Energy savings depends on a number of factors, including the brightness of the LED fixture and the type of light it is replacing. Not surprisingly, brighter LEDs use more energy than dimmer LEDs, but the comparison doesn’t hold true between different types of fixtures — a bright LED might use less energy than a dimmer incandescent, for example, but more energy than a dimmer fluorescent. On average, LEDs use about 70 to 75 percent less energy than halogen lighting; 40 to 50 percent less energy than high-intensity discharge fixtures such as metal halides; and 5 to 10 percent less energy than modern fluorescent fixtures. Online calculators are available that will provide a ballpark energy savings number.
Occupancy sensors are the surest way for LEDs to save a tremendous amount of energy, as they guarantee the lights will only be on and drawing power when they’re needed — an important feature in parts of warehouses that are used infrequently. The sensors don’t work as well for other types of fixtures, however. Cycling fluorescents on and off multiple times per day rapidly degrades the bulbs, and metal halides require significant warm-up time each time they’re turned on. By comparison, the lifespan of LEDs isn’t shortened by cycling, and they reach full brightness instantly.
Q: Can I Have An Example?
A logistics solutions provider for more than 100 years, United Warehouse has a long history of innovation. It was the first warehouse to be registered in compliance with ISO 9002, a quality assurance standard, for example. Though its Tulsa, Oklahoma, warehouses are only 10 years old, rapid advancement in LED technology made the original metal-halide lights seem old-fashioned because of their burnout rate and high energy usage.
To reduce its carbon footprint and improve visibility for employees and guests, United Warehouse purchased a complete LED retrofit from vendor Big Ass Light. Occupancy sensors make each fixture more efficient, and United has already seen more than a 50-percent reduction in lighting energy costs in the year since installation, amounting to about $8,000 to $10,000 per month. The vendor administered local utility rebates at no cost, repaying a large percentage of the projects up-front cost as well.
“We’ve received one full cycle of electrical invoicing, and it’s less than half of what it was a year ago – just because of the Big Ass Lights,” said Mark Vander Veen, United Warehouse COO. “And the quality of light is better, cleaner and more uniform. It’s a nicer looking facility now.”
Forget What You Know
Step one in any research process should be to forget what you know — size doesn’t matter, and neither do watts, in determining the brightness and effectiveness of an LED. There is plenty more to learn about LEDs — talk to neighbors and friends who have them, read online reviews and case studies, and consult with companies that sell lighting, installation and customization to better gauge the pros and cons.
Josh Kegley is a writer for Lexington, KY-based Big Ass Solutions, the parent company of Big Ass Fans and Big Ass Light. Big Ass Solutions manufactures, sells and installs commercial and industrial fans from 18 inches to 24 feet in diameter, as well as industrial-grade LEDs.