Case study
96 metal halide high bays out, LED in, paid back in eight months
A two-shift distribution warehouse cut its lighting load by 67 percent and stopped relamping altogether.
Photographs illustrate the fixture types specified and the difference in light level between 400W metal halide and 150W LED high bays. They are not photographs of this site.
The results
Based on 4,160 run hours a year, an energy rate of $0.128 per kWh, 455W measured draw per 400W metal halide fixture including ballast, and 150W per LED replacement. Rebate figure reflects a prescriptive high bay incentive of $100 per fixture. Your own numbers will differ with your run hours, rate and utility.
The challenge
Ninety-six 400 watt metal halide high bays lit the racking and pick aisles across two shifts. Each one drew about 455 watts once the ballast was counted, so the lighting alone ran close to 44 kilowatts whenever the building was open.
The bigger problem was maintenance. Metal halide lamps lose a third of their output over their life and shift colour as they age, so aisles that were specified adequately were no longer reading as adequate. Replacing a lamp at height meant a lift, two people and a shift working around them. Ballasts were beginning to fail on the oldest fixtures, which meant the failures were about to become more frequent rather than less.
What we specified
A like for like count of 96 UFO high bays at 150 watts, selectable to 300 where more light was wanted over the pick faces. At 16,500 lumens each they cover the 25 foot-candle target for general warehouse storage without adding fixtures, so no new circuits or mounting points were needed.
All are DLC Premium listed, which put the project into the highest prescriptive rebate tier, and we filed the rebate paperwork as part of the supply. Every fixture carries a five year warranty and shipped from US stock, so the install was not waiting on a container.
Planning something similar
Want these numbers for your building?
Send us your square footage, ceiling height and what you are running now. We will put together a free lighting layout, confirm the rebate you qualify for, and quote it. No charge and no obligation.