Before LED lighting became the powerhouse that it is today, the most common form of commercial lighting was metal halide lights. This is because metal halides are extremely bright lights that can be purchased for a relatively cheap price. Nowadays, however, metal halide lights are at best, outdated.
LED lighting provides a long-lasting, economical alternative that saves you money and minimizes energy usage. And, as the technology becomes more and more mundane, LEDs are also becoming less expensive. Making the switch from metal halide to LED in your warehouse, factory, sports stadium or parking lot may appear to be an intimidating task but in reality, and with the right help, it’s a frictionless process.
We’ve been in this space for a while now, and along the way, we’ve received countless questions about how to replace metal halide lights with LEDs. Some of the most common questions are:
“How many LED watts does it take to replace a 1000 watt metal halide bulb?”
“How can I replace my metal halide light?”
“Is it even possible to replace my metal halide fixture with another technology?”
Fortunately, replacing metal halide with LED is simple. The top two questions require a bit more of an explanation than just a simple, one line answer.
This blog is specifically designed to tell you how you can replace metal halide with LED, how many lumens you need, and how to avoid the pitfalls many make when doing this conversion.
What LED Wattage Do I Need to Replace a 1000 Watt Metal Halide?
It seems like a straightforward question but the reality is that it’s a little more complicated than that. LEDs are designed for lower energy consumption, and as such, naturally have a lower wattage.
This means that a 300 Watt LED High Bay is much, much brighter than a 1000 Watt Metal Halide High Bay. Or you can replace a 1000 Watt Metal Halide Shoebox with a 300 Watt LED Shoebox. Therefore, you cannot base your decision on watts. Instead, you need to focus on the number of lumens you need. Once you have that figured out, finding a replacement fixture is easy.
Want help figuring out your facility’s lighting? Request one of our free lighting plans for a customized, lighting layout that eliminates any guessing.
4 Things to Compare 1000 Watt Metal Halide Bulbs with LED
1. Loss of Lumens
Even if you are using a brand new 1000 Watt metal halide bulb, there is a second factor that contributes to lumen loss – the need to use a reflector to focus light. When light is created by an omni-directional bulb, like metal halide, it needs reflectors to gather, collect and focus the light so it can be directed to where its needed.
If a light lumen does more than one bounce inside the reflector, it essentially loses its effectiveness. Reflector design is a science. The better its designed, the less lumens are loss inside the fixture. A metal halide bulb can lose up to 30% of its light in the reflected light bounce.
LED light is directional. It does not need reflectors. Sometime LED lights incorporate optics to distribute the light in a specific pattern. This can also cause a lumen drop, but no where near the lumen loss metal halide suffers from reflective bounce loss.
To put this in real numbers, the brand new 100,000 lumen Metal Halide Bulb may only be producing 70,000 real lumens when installed in a fixture.
“Make sure you understand the difference between metal halide bulb lumens and metal halide fixture lumens”.
2. Quality of light beats Quantity of light!
There’s already plenty to consider when replacing metal halides with LEDs, and we’re about to give you one more. In addition to knowing that LEDs produce a more consistent shine without loss of lumens due to reflection, you should also know that LEDs produce a much higher quality of light. How do we know that? Well, we’ll tell you.
In order to determine the quality of lumens, lighting engineers use something called Color Rendering Index, or CRI. LEDs are available in a wide range of CRIs, starting at about 70 with an upper end of about 98. Metal Halide is actually not that bad, they are offered in a range from 60 to 90. Where LED and Metal Halide really shine is when compared to High Pressure Sodium, that has a CRI of about 22.
CRI matters. In essence, you need less quantity of lumens when you have higher quality.
3. Photopic vs Scotopic Lumens – and the use of S/P Ratios
Photopic lumens is light that is detected by a light measuring device, like a light meter or camera. Scotopic lumens is light detectable by the human eye.
Why is this relevant? Well, LEDs produce predominantly Scotopic lumens. In fact, it’s extremely rare for LEDs to produce any light in invisible spectrums, like UV or IR, unless LED Chips were added to create those spectrums. This is not the case with other types of lighting technologies, like metal halide.
In the lighting industry, S/P ratios were developed to try and level the lighting playing field. Lets study 2 bulbs: a 1000 Watt High Pressure Sodium bulb producing 100,000 lumens and a LED High Bay producing 45,000 lumens. When you install both bulbs, the area under the LED light appears brighter. But how can that be? 100,000 is more than 45,000 lumens That’s where S/P ratios come in.
Using these same bulbs, scientists have assigned S/P Ratios to each bulb based on the quality of light they produce.
LED S/P ratio: 2.0
High Pressure Sodium S/P ratio: 0.5
The scotopic lumens provided by each light source would then be the following:
LED scotopic lumens = 45,000 lumens x 2.0 = 90,000 lumens
HPS scotopic lumens = 100,000 lumens x 0.5 = 50,000 lumens
This is why LED appears brighter. Our eyes detect the higher quality light and it appears brighter than low quality light sources
4. LED Lumens vs Metal Halide Lumens
Essentially, a lumen is a unit of light. It’s the way in which we measure how bright light output is, and it’s how you’ll determine which LED light is best to replace your 1,000-watt metal halides.
A brand new 1000 watt metal halide bulb can produce between 60,000 and 110,000 lumens.
“You do not need to use 1000 Watts of LED to replace 1000W Metal Halide. Don’t focus on watts, focus on the lumens you need to meet your lighting requirements .”
In the above example, the metal halide bulb is operating between 60 and 100 lumens per watt. How do we know this? Its a simple calculation of dividing the lumens of the bulb by the watts consumed.
A 1000 Watt Metal Halide bulb producing 100,000 lumens is operating at 100 lumens/watt. And, while these numbers are not horrible, you have to remember “Metal Halide bulbs suffer from quick and immediate lumen degradation”. So 100 lumens per watt is the best they will ever do. Within 6 months of use, don’t be surprised to see a considerable lumen drop.
From the instant you first flip the switch, the bulb becomes less and less bright. Around metal halide half-life (around 7500 hours of use), that same metal halide bulb producing 100,000 lumens may only be producing 50,000 lumens. But it still consumes 1000 Watts. Energy draw is the same through out the life of the bulb.
At about 5,000 hours of run time, you’ll find that the 1000 Watt metal halide bulb has reached its L70 point. L70 is the definitions of the time it takes for a bulb to reach 70% of its initial lumen output. To give you some context, the L70 time of LED lights is anywhere from 50,000 to 200,000 hours. (depending on the chips used)
How Many LED Lumens Do You Need to Replace 1000 Watt Metal Halide?
If you haven’t noticed by now, there really isn’t an exact answer. Only a lighting plan can tell you exactly how much you need. Between higher CRI, lower energy consumption and available color temperatures, replacing metal halide lights with LEDs can get a little bit complicated. But in our 12+ years of selling LED lighting, you can use this as a starting place.
Indoors: 45,000 to 65,000 lumens (depends on the application and mounting height)
Outdoors: 40,000 to 75,000 lumens (depends on the application and mounting height)
You’ll find that in some instances you can cut energy consumption by up to 75% when replacing a metal halide light. Most LEDs have an efficiency rating of about 130 – 200 lumens/watt.
New generation LEDs tend to be more efficient than older chips. Its a good indication of what you are buying – look at the efficiency of the LED fixture you are looking to buy.
Replacing 1000 Watt Metal Halide with LED
The Easy Path to Replace 1000 Watt Metal Halide
Nothing more than asking us to do a free little planning. To replace 1000 watt metal halides, start with deciding how many foot candles you need. Supply us with your project information, and let us take it from there.
Why do we do this for free? You’ll find out that you having a successful conversion to LED is just as important to us as it is to you.
There nothing feels better at LED Lighting Supply than to get those before and after pictures. We know that if we meet your foot candle requirements, and make the light even and balanced, you’re going to be happy.
About the Author
Dwayne Kula is President of LED Lighting Supply. On any given day, Dwayne is writing content for the site and helps manage the marketing initiatives that are on-going. He has a Software Engineering degree and still dabbles in writing software for the company as needed. When not working, he enjoys spending time with his family, working out, playing the occasional game of golf and exploring New England.