Outfitting a large, high-ceiling space with lighting isn’t the cheapest thing any of us will do this week. Let’s make sure that your next lighting investment hits the mark. No one wants to wind up spending more on lights—and subsequent operating costs—than they really need to, but many err in that direction in order to avoid under-lighting a space. Inadequate light makes it difficult and less safe for employees who have to work in it!
A little knowledge (and sometimes a quick call to our lighting pros) can move you into the sweet spot of just the right spread and intensity of light for your application.
We had all gotten used to wattage as an indicator of brightness. One 400W metal halide bulb was as bright as the next, right? Fluorescent lights threw us for the tiniest of curves when "High Output" versions were introduced, but even then—while a 54W HO light was more efficient than a standard fluorescent light, you could still depend on one 54W HO light outputting the same amount of light as any other 54W HO light.
Then came LED, a lighting technology where, under the forces of continual efficiency improvement, lower and lower wattages drive more and more light. This throws the old, dependable system of wattage = brightness out the window.
For instance, in 2014, the average LED high bay light could be expected to operate at a luminous efficacy of 83 lumens/Watt. If you were replacing a 400W metal halide light, you would have bought a 280W LED alternative, enjoyed a 30% reduction in your lighting costs, and come away thinking that a 280-Watt LED light was equivalent to a 400W metal halide.
Just five years later, you can now replace that 400W metal halide with a value-priced 200W LED high bay or a performance-oriented 150W high bay. That's a 50% and a 62.5% reduction in power consumption, respectively—and both wattages replace a 400 Watt metal halide. That right there shows how wattage is no longer very helpful as an indicator of brightness.
Now that we're talking lumens, we can narrow down what you need based on the height of your space's ceiling:
|
Ceiling Height |
Use a fixture rated |
|
Over 12m |
40,000 lumens & up |
|
9~12m |
30,000 to 39,000 lumens |
|
6~9m |
20,000 to 29,000 lumens |
|
4~6m |
15,000 to 19,000 lumens |
Just where your application falls in that range depends on a few additional factors—for example, what your space is used for. Retail and manufacturing require brighter light at ground level than warehouse and recreation, for instance, and straight-up storage requires even less. Additionally, the size of your space and the color of your walls will affect your light choices.
Our lighting team has assisted with countless LED high bay lighting projects, from gymnasiums to warehouses, from equestrian arenas to airplane hangars, and much more. email (sales@unicornlite.com), or hit up our Live Chat. With just a few questions we can tell you what lumens to look for in your new high bay LED lighting. Getting this right will save you from overspending on too much light or, worse, installing inadequate lighting you'll have to supplement later. Plus, we can assist you with motion sensors, lighting controllers, and other long-terms ways to save the most on energy—and energy costs.
The closer together you install your fixtures, the more overlap the light at ground level will have—and the brighter that light will be. The farther apart you install your lights, the less overlap. Put them far enough apart and, instead of overlap, you'll have gaps. The bigger the gaps, the more uneven your lighting will be at ground level.
Therefore, you'll want at least some small degree of overlap. How much depends on how bright you need your lighting to be at ground level.
Additionally, your spacing will depend on your ceiling height. Light is cone-shaped. At the light source, it's concentrated. As it travels away from the source, it spreads outward. The farther from the source, the wider the spread. So, a light installed 15 feet off the ground has only 15 feet of travel before the light reaches the ground, making its circle smaller than that of a light installed at 30 feet, where it has twice the distance to travel—and spread—before reaching ground.
So, lights installed at only 5m high will need to be closer together to achieve overlap than lights that are installed at 10m. You can use this chart as a basic rule of thumb:
|
Installation Height |
Normal Brightness |
High Brightness |
|
Over 10m |
7m spacing |
6m spacing |
|
6m~10m |
5m spacing |
4m spacing |
|
4m~6m |
4m spacing |
3m spacing |
And, again, our lighting team has a lot of experience with high bay lighting. email (sales@unicornlite.com), or hit up our Live Chat, and we'll not only be able to tell you how many fixtures at what lumens and at what spacing will give you the lighting you're looking for, we can even do up a lighting simulation for you, so you can be certain of what you're getting.
If you've poked around lighting sites, you'll have seen that LED high bay lights don't come in a single design. Learn more about the different styles and their purposes:
In the old days, you had metal halide for high bay lighting, and these lights required not only a lot of power but also a lot of warm-up time to get going. Because the bulbs themselves had a 360˚ beam angle, a lot of the light shone up into the fixture rather than down where you needed it. To combat this, metal halide fixtures had reflectors added.
LED lights don't need that. Because of the directionality of LED lighting, the full amount of light is directed where it's actually used. And, with no reflector, the shape of these HID replacements has earned them the name "UFO high bays."
Metal halide lamps also run extremely hot, and they burn out after 20,000 hours (15,000 for higher-wattage lamps)—but before burning out, they dim—quite significantly. You could expect to lose 50% of your light output halfway through the bulb's rated operating life.
Today's UFO high bays, relying on LED technology, are able to outperform metal halide in every aspect. Half the operating cost, twice the operating life, all the brightness, and after 50,000 hours, they'll still be putting out at least 70% of their original rated lumens.
We have a wide selection of UFO LED high bays to meet any ceiling height and application requirement.

You're replacing metal halide fixtures and want to keep the same layout
Your space is a large, open area, as a factory floor, gymnasium, airport, etc.
Your ceilings are over 10m
You need protection against dust, moisture, or water (round high bays are generally IP65 rated)
In the past, linear high bays have been fluorescent T5HO lights, for ceilings over 6m, and T8 or T12 for ceilings under 6m. T5HO technology was intended to be the high-efficiency alternative to metal halide high bay lights, and many properties were switched over to these lights, but they never quite lived up to their promise as a metal halide replacement.
As an alternative to linear fluorescent high bays, LED linear high bays actually do provide light as eye-popping as metal halide lamps while running at significantly less power (significantly less even than T5HO lamps) and lasting years longer without maintenance. Take a look at our linear LED high bay lights, suitable for both open areas and aisle lighting.

You're replacing linear fluorescent fixtures and want to keep the same layout
Your space has aisles, assembly areas, or other specific rectangular footprints you want to follow
We have developed a variety of high bay lights for different applications, such as anti-glare high bays suitable for sports lighting or spaces with high foot traffic; high bays with plug-in sensors for effective energy saving; and high bays with special optical angles, adjustable power and color temperature, suitable for various venues and projects.
Please feel free to contact our team anytime; we will provide you with the most professional advice.