It’s 2021, so we all know that converting from Metal Halide (HID) lighting to LED lighting will save you money. The real question is how much money will it save you and why? The major and most well-known difference between metal halide bulbs and LED lights is that LEDs are much more energy-efficient. But, this isn’t the only reason that LED lighting is superior to HIDs. In fact, it’s just one of many. 

Here, we’ll break down everything that you need to know about the differences between Metal Halide Lights and LED lights. Spoiler alert: LEDs are better. But how much better are they? Read on to find out.

Battle of the Bulbs – 9 Reasons LEDs are Better

1. Lumens Efficiency

First, we’ll take a look at the average stats of a typical 400-watt metal halide bulb.

 

400 W HID

Color Temperature

4000K

Initial Lumens

32,000 – 36,000

Life Hours

20,000

 However, a white paper by the Dark Sky Society rated the mean lumens for a 400W Metal Halide to be 20,500 lumens and the life expectancy to be around 15,000 hours. This paints a much better picture of how HIDs behave in real life because it takes into account the very real problem of lumen degradation. 

As you can see, a metal halide bulb starts out with an extremely high lumens output. But, the keywords there are “starts out with.” It is not uncommon to lose 20% of those lumens within the first 6 months of use. So while 36,000 lumens certainly sounds impressive, you won’t get to enjoy that powerful shine for long. Chances are that within 6 months your new HID light will be below 30,000 lumens.

LED lifespan

Lumen depreciation in a metal halide bulb is quick, really quick. At half-life of the bulb, around 8,000-10,000 hours, lumen depreciation is already at 50%. 

In addition to losing the majority of light output as the fixture is used, metal halides also suffer from lumen loss as soon as you turn the light on. Although you technically are not actually experiencing a loss of lumens, a percentage of them immediately becomes ineffective. 

This is because a Metal Halide bulb is omnidirectional. Omnidirectional means that the light from the fixture distributes in every direction. So it produces as much light parallel to the ground as it does facing downwards.

In order to make this parallel shine useful, you need to gather it, collect it, and focus it Metal Halide fixtures use reflectors to do this. The problem with this is that it causes you to lose some of the brightness of the light. 

A lumen that bounces off the reflector and bounces back into the fixture is a lost lumen. Any light particle that bounces more than once can be considered a throw-away. You can lose as much as 30% of the light in this reflective bounce.

We’ve given you the facts, so now it’s onto the figures. In an industrial indoor bay fixture, we assume the initial lumens of the lamp at 36,000 lumens. After 6 months we would expect the fixture effective lumen efficiency to be:

36,000 lumens – 20% (initial lumen loss) = 28,800 lumens

Lumens loss from reflector bounce: 8,640

Total lumens after 6 months in indoor bay fixture: 20,160

This also does not take into account any lenses or shields that the fixture might already have, which would decrease lumens even further. We refer to this number as bulb lumens. Figures that take into account lenses or shields on the fixture are called fixture lumens. 

Now, let’s compare this to an LED light. Whether its a brand new LED fixture or one of our LED Retrofit Kits that replaces HID, all the light an LED produces is directional and therefore does not require reflectors. In addition, although lumen depreciation does also happen to LED lights, as you can see in the above graph, it takes much, much longer.

2. LEDs Superior Operating Life

As mentioned, the operating life of a typical Metal Halide bulb is around 20,000 hours. However, larger bulbs, such as 100W metal halide, are around 15,000 hours. And in commercial and industrial settings where you’re likely using much more powerful lights, this drop in lifespan is significant. 

There are several different ways suppliers describe the life of a product. One of these ways is to measure lifespan via the L70 method. L70 is not a measurement of the end of a light’s life. Instead, it is a measurement of lumen degradation up to 70% of initial lumens. This measurement does not include external circumstances, like if the driver or ballast or some other component were to fail. 

The life of a Metal Halide bulb is around 15,000 to 20,000 hours. But, at the light’s half-life, it has already lost 50% of its initial lumens. So while it’s not necessarily dead, it’s definitely ineffective. And, just so you have the full picture, even though the light isn’t producing at its initial lumen output, it still consumes 400+ watts.

3. Efficacy (lumens/watt) – LED vs Metal Halide

Efficacy is a measurement of how well a light source produces light. In this case, we’ll be comparing LEDs and Metal Halides, but all bulb types can be quantified with this measurement. Understanding efficacy is also important to understand why LEDs save you so much on energy costs.

Here’s how to calculate lumen efficiency. Take the total lumens produced and divide it by the total watts consumed. In the case of Metal Halide lights, you’ll also need to include the ballast draw.

On average, the total watts consumed by a 400 Watt bulb, is around 455 watts. And, the ballast consumes about 15% more energy over and above the bulb consumption.

So calculating lumen efficiency for metal halide: 36,000 lumens / 455 watts = 79.12 lumens/watt.

Let’s compare that with our 150 watt Retrofit Unit: 23,250 lumens / 150 watts = 155 lumens/watt. Almost double of Metal Halide.

Remember the golden rule: Efficacy Saves Money!

4. LED vs Metal Halide Energy Savings

Now that you understand efficacy hopefully, you have a little more insight on how and why LEDs are energy efficient. They are able to produce more lumens with less wattage. Which means if you replace a metal halide bulb with an LED, you’ll have a brighter light that also consumes less electricity. We call that, a win-win.

In the above example, we compared a 400 W metal halide bulb with a 150 W LED retrofit kit. This showed just how much more efficient LEDs are, but now how much more powerful they are.

 

The truth of the matter is that we wouldn’t recommend replacing a 400W metal halide with a 150W retrofit kit. Instead, we recommend a  100 Watt Metal Halide Retrofit Kit.  

This particular LED light produces 15,500 lumens. So why do we recommend a light with fewer lumens? We’ll get into this more later but LEDs produce a higher quality light, which means that you need fewer lumens.

And, we’re willing to put out money where our mouth is to prove this. Here is a recent example by a customer who wanted to compare our retrofit kit to his existing Metal Halide fixture. Here, you can clearly see that the LED retrofit kit is brighter than the metal halide, even though it produces fewer lumens. In fact, it’s bright enough to cast a shadow where the metal halide light is already shining.

5. LED Wins with Savings on Maintenance

Far and wide, LEDs are touted for being energy-efficient lights that save you tons of money on your electrical bill. However, this is not the only place where LEDs will save you money over metal halide bulbs. An often forgotten aspect of LED lighting is its low maintenance requirements. 

When we discussed the lifespan and efficiency, we mentioned that over the life of one LED product, a customer would have to do 5-6 bulb replacements on a metal halide light. Replacement bulbs add up fast, especially when you’re replacing bulbs for an entire warehouse or factory. And, the higher the installation height, the higher the cost of replacement. If you have a facility loaded with lights, this cost of replacing bulbs every year adds up quickly. 

The money you save on replacement bulbs admittedly won’t be as much as you save on your energy bills. However, these low maintenance lights save you more than just money. They save you and your employees time. Employees can delegate their hard work to much more important tasks, instead of switching out light bulbs, which will improve overall efficiency and productivity.

6. Quality of Light – LED has high CRI

When you use a light meter to take the measurement of a light’s output, it reads lumens. Metal Halide creates all sorts of light, in all spectrums, visible or otherwise. This includes UV and IR spectrums visible to the measuring device but not visible to the human eye. LEDs, on the other hand, doesn’t produce UV and IR, so it’s all visible to the human eye. 

Like lumens, foot candles are also a measurement of light intensity. One foot-candle is defined as enough light to saturate a one-foot square with one lumen of light. So instead of measuring the amount of light that leaves a light source, foot candles measure the amount of light that reaches a surface area. 

If you compare Metal Halide lights and LED lights, you’ll likely find that the metal halide lights have a higher foot-candle measurement, while the LEDs have a higher lumen output. But, keep in mind that much of the light that the light meter is reading from a metal halide isn’t even visible. So, while metal halides may have a higher foot candle, LEDs produce more, usable light.

light bulbs cri
Another factor that plays into the way we perceive light is accounted for by the Color Rendering Index, or CRI. CRI is a measurement of Quality of Light. On a scale between 0 and 100, 100 is excellent. And LEDs tend to have a high CRI value. This allows us to perceive color more accurately and helps prevent eye strain and headaches. With LED lighting, you’re choosing quality over quantity and reaping the benefits.

7. Photopic vs Scotopic Lumens

Photopic vs scotopic lumens is a discussion of how humans see light (scotopic) vs how a light meter perceives light (photopic). The human eye uses rods and cones to perceive light and color. Rods are responsible for vision during low light, and don’t pick up color. 

What’s important here is to recognize that our eyes read light in a very different way than light meters. In order to account for this difference, scientists came up with a new way to measure light,  S/P Ratios.

These ratios compare different light sources by how light appears: scotopic versus photopic. And use factors between 0 and 3 to give an accurate measurement. The S/P factor for LEDs is always higher than the ones associated with Metal Halide lights.

8. Works great with Photocells, Motion Sensors and other controls

LED has two features that metal halide just cant compete with.

1. Instant On / Instant Off

2. Dimming

While alone these features are great features, when matched with lighting controls, they turn lighting into a smart appliance that is bright when needed and even more energy savings when its not.

Motion sensors detect motion. A light needs to increase brightness when motion is detected. With LED, and its ability to get bright quickly, this is simple. When motion leaves the area, the light can either turn off or dim. Because LED is dimmable, this isn’t a problem. Fixtures can be set to dim to certain levels when no one is in the area, or even off.

With Metal Halide, it suffers from extremely long strike times. Metal Halide takes up to 30 minutes to go from being turned on to full power. And as much time to cool off before it can go on. Dimming is not an option. Before LED, motion sensors were not a good match with Metal Halide. Now, it is extremely common to see lighting controls matched with LED.

And when a light is dimmed or off, energy saving is even greater. So when you’re calculating converting from Metal Halide to LED, consider adding a light control. Consuming 400 Watts Metal Halide to 10 Watts LED (100 Watts dimmed to 10%) is an incredible energy savings.

9. Rebates at time of purchase

Demand for electricity grows every day, but this is a finite resource. There’s only so much energy that a power company can produce each day. In order to combat this ever-growing need for electricity, power companies are offering rebates to customers that make energy-efficient upgrades. 

An easy way to earn a rebate is to convert from Metal Halide to LED. Every utility company runs their own rebate program. But in general, there are some consistent processes and guidelines. For the most part:

Utilities offer both prescriptive and custom rebate options. A prescriptive rebate specifies which LED fixtures can replace a metal halide fixture. A custom rebate is for those exceptions not covered by prescriptive conditions.

And, generally speaking, the LED products need to be DesignLights Consortium Qualified. This is a universal symbol of efficiency and performance. It can be thought of as the equivalence of Energy Star for consumer products. It tells the customer the lights passed a specific lighting standard.

These rebates help reduce the initial cost of installing LED lights and will speed up the pay back period. Rebates aren’t the only incentive to switch to LED lighting, but they sure are a good one. 

With Metal Halide there are no rebates. Sorry.

We Have a Winner – Converting to LED

As you can see, LED lights win every matchup against Metal Halides. LEDs save you money, increase efficiency, improve productivity, and can even earn you some extra money. They also produce a brighter, higher quality light with little to no lumen waste. But this is just the beginning of your LED journey.  To recap:

 

LED

Metal Halide

Color Temperature

LEDs are available in a wide range of color temperatures from 2700K (warm yellow) to 6500K (cool blue).

Metal halide lamps generate a white light between 3000K and 5000K.

Color Rendering

CRI for LED is dependent on the particular light in question. That said, a very broad spectrum of CRI values is available ranging generally from 65-95.

Metal Halide are a good source of high CRI white light. It is a better light than high pressure sodium.

Turning On and Off

LEDs are an instant on and install off. No noticeable strike time is detectable.

Metal Halide lights have a long warm up time and can take 15-30 minutes to get to full power.

Dimmable

LEDs are controllable when equipped with the proper driver. Most industrial dimmers are 0-10V dimmers. Commercial consumer LEDs are triac dimmable using a regular LED compatible dimmer switch.

Metal halide lights are dimmable using electric or magnetic ballasts.

Directionality of Light

LEDs are directional and the light goes where pointed. Without optics, reflectors are not required unless you need a specific distribution pattern.

Metal Halide lights are omni-directional emitting light in a 360 degree pattern. To focus the light, reflectors and lenses can be used to collect the light and then direct it as needed.

Lumens per Watt

LEDs are very efficient with efficiencies approaching 200 lumens/watt. Not all LEDs are the same, and efficiency varies from product to product.

Metal Halide lights average efficiency range between 70 and 100 lumens/watt. This does not include ballast draw which can add 

another 15% of energy consumption.

L70 in hours

LED L70 times (years passed until lumen output reaches 70% of initial lumens) range from 30,000 to over 200,000 hours.

Metal Halide lights have a very quick L70 period, when a bulb reaches 30% of its life, it has reached its L70 mark. When a bulb is at 1/2 life, it is only producing 1/2 of its intial lumens.

Light Emissions

LEDs do not produce Ultra Violet or Infrared Light unless designed to do so. The light it generates is all visible light.

Metal Halide lights produce both IR and UV light.

Heat Emissions

LEDs produce very little heat. All LED lights do requires some sort of heat sink to reduce the heat produced by the LEDs.

Metal halide bulbs produce a tremendous amount of heat. Fixtures designed for Metal Halide must be large enough to handle the heat generated. A Metal Halide bulb turned on for a few hours is far too hot to touch.

Failure

LEDs fail over time by producing less light.

Metal Halide bulbs exhibit an end-of-life process called cycling. The lamp may go on and off. The bulb will fail at some point.

Lifespan

Industrial LEDs last between 50,000 and 100,000 hours or more. The lifespan of a LED driver is different than the LEDs themselves. It may be possible to replace the LED driver in the fixture to extend the life of the product.

Metal Halide lights have typical bulb lifespan values range from 6,000 hours to 20,000 hours. Metal Halide ballasts operate on a different life cycle with it’s own lifespan cycle.

Lifetime Costs

LED lighting has higher initial cost and very low lifetime costs. It pays back over time with lower energy consumption and reduced maintenance costs.

Metal halide lights have a lower initial cost but are expensive to maintain. Metal halide bulbs consume more energy than a LED Fixture and have a higher maintenance cost.

Maintenance Costs

There are few maintenance costs associated with LED during the lifespan. Only fixture cleaning if needed.

Metal Halide bulbs need regular re-lamping and ballast replacement. It is not uncommon to do 4-6 bulb replacements over the lifespan of a comparable LED product.

Shock Resistance and Impact Rating

LEDs are solid state lights which are difficult to damage. In extreme conditions, look for lights with an impact resistance rating (IKxx)

Metal halide bulbs are fragile. If broken, metal halide bulbs need special handling and disposal.

Temperature Conditions

Varies, but -30C to 50C is pretty common. Extreme LED fixtures are available up to 90C

Data shows -40C to ??

Warranty

5 to 10 years

1 to 2 years

You know LEDs are better, but that’s just the start of your journey. Now it’s time to make the switch. LED lights are more expensive initially, but between rebates, low maintenance costs, and massive energy savings, you’ll see a quick return on investment. And, there’s always the option to retrofit to further cut back on the cost. There are many different things to consider, but converting from metal halides to LEDs is unquestionably a good decision.  

1