A HID fixture is a lighting device that consists of a fixture, a HID bulb, a ballast, reflectors and a mount. HID is an acronym for High Intensity Discharge, and applies to a family of high lumen bulbs. Mercury Vapor, Metal Halide. Ceramics, Sodium Vapor and Xenon based bulbs are all considered to be HID bulbs. All HID bulbs need a ballast that converts AC line power into energy used to power the HID bulb.
The bulbs are omni-directional in nature, and they create light in all directions. To focus HID lights, adding reflectors and lenses to the fixture to direct the light where its needed. HID bulbs are very bright, but required a long strike time to produce greatest levels of light. If you switch off a fixture, the amount of time it takes to re-cycle the fixture is considerable. The two most common HID bulbs are metal halide bulbs and sodium vapor bulbs. Both bulbs are distinctive. Sodium bulbs are orange in color, metal halide are whiter.
Applications for HID Fixtures
HID fixtures are for high lumen applications. Indoor applications like gymnasiums, warehouses, bay fixtures, recessed lights and factory lights. Outdoor applications include parking lots, stadiums, street lights and area lights. HID bulbs come in a variety of wattages for different applications.
Large fixtures with high wattage bulbs use 1000W, 1500W and 2000W HID bulbs.
Smaller bulbs used in bay fixtures and parking lit lights use 250W and 400W bulbs.
Smaller wall mounted fixtures with less lighting requirements, 100W and 150W bulbs.
Life of a HID bulb
HID bulbs have different lifespans, between 12,00 hours to 20,000 hours. During this lifespan, light out degrades with the age of the bulb. It is not uncommon that after 1/2 life of the bulb, the HID bulb has lost over 50% of its effective lumens. A bulb that has used 80% of its life is only producing 20% of its initial lumens. Thus, it is not uncommon to replace bulbs well before complete End of Life.
A phenomenon associated with HID lamp wear and aging is discoloration of the light. In whiter based HID bulbs, this means the shift is to a blue or violet shade.
Converting HID Fixtures over to LED
So why are users of HID Fixtures converting to LED? When LED was in its infancy 11 years ago, LED barely produced enough light to replace HID bulbs. LED was inefficient, and expensive. Today, LEDs have matured, and mass production has brought down the cost of the product. LED options now produce enough lumens to compete against their HID counterparts. LED offer several advantages over the HID fixtures.
LED is energy efficient, using 25% of the energy that a HID bulb uses to produce the same amount of lumens.
LED’s life spans are longer than HID bulbs. A 20,000 hour HID bulb has a L50 of 10,000 hours. Some LED fixtures currently have a L70 exceeding 100,000 hours.
The purity of LED light is better than HID lighting. Some metal halide bulbs have a high Color Rendering Index (CRI), but most LED products have a high CRI. Sodium Vapor bulbs have a horrible CRI.
Replacing HID fixtures or Retrofitting HID Fixtures
There are 2 options that are available converting HID to LED: replace or retrofit. Replacement means removing the fixture and a installing a new LED fixture. Retrofit is removing HID components from the fixture and replacing with LED components. Both options have pros and cons. Which one to use depends on circumstances unique to the fixture and installation.
LED Kits for HID Fixtures are a series of 11 kits designed to replace all HID bulbs ranging from 150W to 1500W. HID Retrofit Kits are a certified retrofit solution. As part of the installation process, remove the reflector as it is not required. Expect energy savings around 75% over their HID counterparts. Life span should exceed 10+ years under normal operating conditions.
We all know that converting from Metal Halide (HID) to LED will save you money. But how much? Are there any other reasons or difference you should know about with LED vs Metal Halide lights?
In this article, we break down the factors you should be aware of before deciding to convert from Metal Halide to LED. Here are the 9 reasons LED wins over Metal Halide.
1. Lamp (Source) Efficiency Vs Fixture (System) Efficiency
Let’s take a look at the information on a typical 400 watt metal halide bulb. A popular online website shows the specications a new Metal Halide bulb
Color Temperature: 4000K
Initial Lumens: 32,000 to 36,000
Life Hours: 20,000
A white paper by the Dark Sky Society rated the mean lumens for a 400W Metal Halide to be 20,500 lumens. The rated life expectancy to be around 15,000 hours. But for purposes of this discussion, we will stick with the numbers we are familiar with.
There is a lot of interesting information to look at. Initial lumens is a very high number. But in reality, a Metal Halide bulb starts off very bright and then quickly drops its lumens. It is not uncommon to lose as much as 20% in the first 6 months alone. So while 36,000 lumens sounds impressive, within 6 months, it can be below 30,000 lumens. Lumen depreciation in a metal halide bulb is quick. At half life of the bulb, around 8,000-10,000 hours, lumen depreciation is already at 50%.
Let’s look at the operating nature of the bulb. A Metal Halide bulb is omni-directional. That means light distribution in every direction. So it produces as much light parallel to the ground as it does facing downwards.
To make this light useful, you need to gather it, collect it, and deliver it to where you want it. In fixture design, you add a reflector to do this job. Reflected light’s issue is how effective is the reflector getting bounced light downward. A lumen that bounces off the reflector and bounces back into the fixture a lost lumen. Anything more than one bounce is throw-away. You can lose as much as 30% or greater of the light in this reflective bounce. So lets do the math of a metal halide bulb. 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:
Total lumens after 6 months in indoor bay fixture: 20,160
This does not take into account any lenses or shields that the fixture might already have. Keep in mind, this is bulb lumens, not fixture lumens. So anything else that gets in the way of moving light to the ground will always take away from effective lumens.
Compare this to LED. If you think of a LED fixture or one of our LED Retrofit Kits that replaces HID, all the light is directional. Reflectors are not required. There is nothing to reflect. Lumen depreciation, it does happen in LED, but it takes a lot longer for it to happen. For example, our retrofits have a L70 (lumen depreciation to 70% of initial lumens) of over 100,000 hours. Metal Halide loses a lot of lumens in the first 6 months of life, LED tends to maintain its lumens for a lot longer.
2. Operating Life
As mentioned, the operating life of a typical Metal Halide bulb seems to be around 20,000 hours. Larger bulbs, like a 1000 watt Metal Halide, are around 15,000 hours. LED solutions, there are different ways suppliers describe the life of the product. One way is to mention L70. L70 is not a measurement of end of life, but it is a measurement of lumen degradation up to 70% of initial lumens. This does not mean the driver or ballast or some other component might fail.
What we do know is the life of a Metal Halide bulb is around 15,000 to 20,000 hours. What we also know is that at half life, it has already lost 50% of its initial lumens. So while not dead, it’s ineffective. For the record, it still consumes 400+ watts even though it is half as bright.
Compare that to our Retrofit Products rated at 100,000 hours (L70). So by the time the LED head reaches 100,000 hours, you have done 5 Metal Halide bulb replacements, possibly more.
3. Efficiency (lumens/watt)
This is the pre-cursor to the next topic, energy savings. But the basic premise is the more efficient the bulb is, the more money you will save. So let’s calculate the lumen efficiency of metal halide versus LED.
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, you also have to include ballast draw. If you recorded the total watts consumed of a typical 400W bulb, it is around 455 watts. 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.
And remember the golden rule: Efficiency Saves Money!
4. LED vs Metal Halide Energy Savings
So in the above discussion, lets point out something important. Above we talked about the mean lumens of a 400W Metal Halide to be around 20,500 lumens. Our 150W retrofit kit produces 23,250 lumens, but instead of burning 455 watts, it consumes only 150 watts.
That represents a 66% savings in energy consumed to produce more light. But the truth of the matter, 23,250 lumens to replace 400W Metal Halide is over kill. For years, we have been selling our 100W HID Retrofit at 15,500 lumens to replace 400W Metal Halide. Here is a recent example by a customer did. He wanted to compare our retrofit kit vs his existing Metal Halide fixture.
In the comparison picture below, the LED produces so much light it casts a shadow from the pole in the light generated by the metal halide light.
5. Savings on Maintenance
We have just as many customers wanting to convert to LED because of maintenance savings as they do for energy savings. Think about what we discussed, over the life of the LED product, a customer would have to do 5-6 bulb replacements. The higher the installation height, the higher the cost of replacement. And if you have a facility loaded with lights, this becomes a significant budget amount every year that you must take into consideration.
Now, we know that reduced maintenance time on lights does not translate into dollars saved because it is highly unlikely that people will lose their jobs over the fact there is much less work to do. However, these people will have time to now work on things that matter, like fixing the machines that make the company money instead on replacing lights that cost the company money.
6. Quality of Light
When you take a measurement of light with a light meter, it reads lumens. Foot candle is a measurement of all the fixture contributing to light at a location. But let’s think about that light that is being measured. Metal Halide creates all sorts of light, in all spectrum’s, visible or otherwise. This includes UV and IR spectrum’s, visible to the measuring device but not visible to the human eye. LED does not produce UV and IR. Light produced by LED is all visible to the human eye.
So there is a fun little test you can do. Have 2 light sources, LED and Metal Halide. And first ask, which one is brighter? In many instances, it should be the LED Light source. And then use a light meter, and the light meter may say the Metal Halide area is producing more foot candles. And so now you know part of the reason, but wait, there’s 2 other pieces of information you need to know.
One is Color Rendering Index, or CRI. It is a measurement of Quality of Light. It’s a scale between 0 and 100, 100 is excellent. And LED tends to have a high CRI value. So the other golden rule we say is “You need less quantity when you have more quality”. Metal Halide bulbs can be good, and are much better than High Pressure Sodium. But LED tends to be much better, so we perceive the light generated by LED to be brighter. More about this in the next section.
7. Photopic vs Scotopic Lumens
Many years ago, the discussion of photopic vs scotopic lumens as voodoo magic talk. There were those who believed in the difference and as many who discounted it. This is a discussion of how humans see light (scotopic) vs how a light meter perceives light (photopic). It is true people are able to see, and light is a big part of why we are able to see. Walk into a dark bat cave and you will understand how important light is. Our eyes consist of rods and cones, and how they work allows us to see colors and perceive objects at night. You will notice that it is harder to see colors in the dark. That is how our eyes work. Cameras and light meters work differently. They detect light differently. But what they do read they register and they interpret what it is ‘reading’.
Then scientists and physicists came along and they tried to make sense of this. And they came up with this concept of scotopic lumens. They took it a step further and created a series of factors. It compares different light sources and how lights appears scotopically versus how a light measures photopically. What came out was a series of factors between 0 and 3. Some light sources have reduced effective lumens, like High Pressure Sodium. Some light sources increased by these factors, like LED. The factor associated with LED was higher than Metal Halide. It helps to understand why LED Lights are brighter than other light sources. Even though the light meter tells us something different.
8. Rebates at time of purchase
Utility companies are trying to get their customers to convert to LED. Why? It’s a matter of economics for them. Demand for electricity is growing. So once they reach capacity, they have to choices, build more capacity or reduce demand. Reducing demand is far more cost effective than increasing capacity. So the utility companies offer rebates to purchase LED. They want you to convert from Metal Halide. 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 is a definition of what LED bulbs replaces what Metal Halide fixture. A custom rebate is for those exceptions not covered by prescriptive conditions
Most LED products need to be DesignLights Consortium Qualified. This is a symbol of efficiency and performance. It is the equivalence of Energy Star for consumer products. It tells the customer the lights passed a specific lighting standard.
These rebates help reduce the cost and will affect the pay back of the investment. With reduced cost, the time to repay the investment goes down with addition of rebate dollars.
With Metal Halide, no rebates. Sorry.
9. New versus Retrofit
So at this point you are thinking that converting from Metal Halide to LED is a good idea. But this is where the journey begins. What to choose, what vendor to work with, new or retrofit. Think of the LED Market as the wild west. And with every gun show there are the snake oil salesman trying to get you to buy their lotions. In the LED world, there are many lotions, misconceptions and marvelous marketing ideas. For example, well built LED Retrofits will perform as well as a new LED fixture. It doesn’t always make sense to replace the fixture, nor does it always make sense to retrofit a fixture.
Comparison Table of LED vs Metal Halide
LEDs are available in a wide range of color temperatures from around 2700K (warm yellow) to 6500K (cool blue)
Metal halide lamps generate a white light between 3000K and 5000K.
CRI for LED is highly 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 perhaps the best source of high CRI white light on the market. It is a significantly better light than high pressure sodium
Turning On and Off
LEDs are an instant on and install off. No noticeable strike time is detected
Metal Halide lights require a long warm up time and can take 15-30 minutes to get to full power.
LEDs can be dimmed when equipped with the proper driver. Most industrial dimmers are 0-10V dimmers, while commercial consumer leds are triac dimmable using a regular LED compatible dimmer switch.
Metal halide lights can be dimmed using different electric or magnetic ballasts.
Directionality of Light
LEDs are extremely directional and generally the light goes where it is pointed. The use of reflectors is typically not required unless a specific distribution pattern is required without the use of optics.
Metal Halide lights are omni-directional meaning they emit light in a 360 degree pattern. To focus the light, reflectors and lenses are added to collect the light and then direct it where it is needed.
Lumens per Watt
LEDs are very efficient, and efficiencies approaching 200 lumens/watt is becoming a commercial reality. However, 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 may include another 15% of energy consumption.
L70 in hours
LED L70 times (years passed where lumen output reaches 70% of initial lumens) and can range from 30,000 hours to over 200,000 hours.
Metal Halide lights have a very quick L70 period, typically 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.
LEDs typically do not produce Ultra Violet or Infrared Light. The light it generates is all visible light.
Metal Halide lights produce both IR and UV light.
LEDs produce very little heat. That being said, 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 bulbs must be large enough to handle the heat generated by these bulbs. A Metal Halide bulb turned on for a few hours should not be touched.
LEDs fail gradually 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 eventually fail.
Industrial LEDs last between 50,000 and 100,000 hours or more. However, the lifespan of a LED driver is different than the LEDs themselves, and it may be possibly 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. Like LED, Metal Halide ballasts operate on a different life cycle, so they will have their own lifespan cycle.
LED lighting has relatively higher initial purchase cost and extremely low lifetime costs. The technology pays back over time (the payback period) with lower energy consumption and reduced maintenance costs.
Metal halide lights are relatively purchase cost but are expensive to maintain. Metal halide bulbs consume a lot more energy to a comparable LED Fixture and has a much higher maintenance cost.
Typically there is no maintenance costs associated with LED during the lifespan, other than fixture cleaning if installed in a dusty area.
Metal Halide bulbs require 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 relatively fragile. If broken, metal halide bulbs require special handling and disposal.
Varies, but -30C to 50C is pretty common. However, extreme LED fixtures are available up to 90C
Data shows -40C to ??
5 to 10 years.
There you have it, 9 highly backed up and legitimate reasons the fight of LED vs Metal Halide is no longer a fight. LED is a clear winner in every aspect of a light. We think of it as the perfect HID Replacement.
How many LED watts does it take to replace a 1000 watt metal halide?
It’s a simple question that requires a complex answer. You can’t base your decision entirely off of watts. Instead, you need to base your decision based on the amount of lumens you need. Once you get the lumens dialed in, find a fixture that produces that lumen amount.
What is a lumen?
In simple terms, it’s a unit or measurement of light. For light fixtures, we calculate the total lumen output. That tells us how bright the fixture will be.
Why does this matter? A lot more than you may think. Because it’s what matters when replacing old light systems.
When replacing an existing fixture, determine the lumen output per fixture. Metal halide fixtures, with fresh bulbs, output at 100,000 (initial) lumens per 1000 watt bulb. You do not need to replace 1000W Metal Halide with 1000W LED. Instead, you need to find the equivalent replacement for the 100,000 lumens. You can forget about replacing watts and focus on replacing lumens.
In the above example, 1000W producing 100,000 lumens, the effiency is 100 lumens per watt. In the world of today’s lighting, this is OK, but not great. You need to be aware of some other factors going on.
Understanding Initial Lumens and L70
100,000 lumens may seem bright. It is. Metal Halide bulbs have high initial output. They suffer from fast lumen depreciation. It is common for a metal halide bulb to have lost 50% of it’s lumens at half-life.
L70 is a term for the number of hours before a bulb is performing at 70% of initial lumen output. For metal halide, 70% of its lumen output calculates to about 5000 hours. So, while the specs say 100,000 lumens, it won’t be 100,000 lumens for long. LED maintains its lumens much better.
You will notice L70 times for LEDs are 50,000 and 100,000 hours, not 5,000 hours like it is for metal halide bulbs.
Loss of Light due to Reflection
LED light is directional. HID light sources are omni-directional and need reflectors to focus light. Any reflected lumen that bounces more than once is a lost lumen. Studies show that you can lose up to 30% of the effective lumens in the reflective process.
If a metal halide bulb has 100,000 initial lumens, the loss associated to reflected lumen bounce is around 30,000 lumens.
Quality of Lumens
This relates to Color Rendering Index, or CRI. Its a measurement of quality, not quantity. The higher the quality, the less quantity you need. Often, customers tell us that 20,000 LED lumens appear brighter than 40,000 HID lumens.
The basic truth is you need less quantity when you have higher quality.
Photopic vs Scotopic Lumens
This has to do with how a camera perceives lumens versus how humans perceive lumens. Photopic lumens is light detected by a light meter or camera. Scotopic lumens are lumens detected by the human eye. LED produces visible scotpic light. It is rare to see a LED light produce IR or UV invisible spectrums. These wavelengths are invisible to people, so they have no value to us from a vision perspective. Light meters detect invisible spectrums, giving a false perception of brightness.
The science of scotopic lumens includes a factor used to adjust the photopic value to give a true representation of how “good” the lumens are. This factor is the S/P ratio. The S/P ratio attempts to level lumen quality between light sources. The factor adjusts the effective value of lumens, up or down, from the photopic lumens.
Assume you have an 40,000 lumen high-pressure sodium (HPS) fixture and a 12,000 lumen LED fixture. Is the LED fixture capable of replacing the HPS fixture? Based on this data, you may think that the LED will only deliver 25% of the light provided by the HPS light. Consider the following S/P ratios:
LED S/P ratio = 2.0
HPS S/P ratio = 0.5
The scotopic lumens provided by each light source would be the following:
LED scotopic lumens = 12,000 lm x 2.0 = 24,000 lm
HPS scotopic lumens = 40,000 lm x 0.5 = 20,000 lm
The LED would appear brighter even though it is 28,000 less lumens.
Light sources with higher scotopic factors need less lumens for us to perceive and detect the light.
Putting This All Together
The basic takeaway from this is you need far fewer LED lumens than metal halide or HPS lumens.
Metal Halide bulbs are very bright out of the box, but degrade quickly.
LED light is directional. LED light goes where its pointed. It is very efficient.
LED light is high quality light. You need less quantity.
So how much LED Lumens do you need?
Only a photometric can tell you exactly how much you need. But in our 10+ years of selling LED lighting, our general rule of thumb is:
Indoors: 45,000 to 65,000 lumens (depends on application and mounting height)
Outdoors: 40,000 to 75,000 lumens (depends on application and mounting height)
By searching for LED to replace 1000W HID you can find LEDs that are more efficient than 100 lumens/watt. Lumen efficiency for LED is getting closer to 200 lm/watts. This will allow a cut of watts used by 75% or more.
But What Does “replacing” Consist of?
Replacing can consist of two things: retrofitting or full replacement. The difference is simple, a retrofit kit is like replacing the light source in the fixture. While full replacement includes replacing the existing light source and fixture. To be able to decide which one is best for you will depend on your facilities’ situation. If your existing fixture shell is in good condition, retrofitting will work. If they are old, outdated and need replacing, a full replacement is the best option.
Are the LEDs in a retrofit kit as good as a LED fixture
Yes. Despite of what you have heard, there is no reason to believe that a retrofit/hid replacement won’t perform or last as long as a new fixture. Retrofits don’t always make sense. But they do if you have a significant investment in your fixture or the look of your fixture. Our retrofit kits have 10 year warranties. They have been installed inside sealed fixtures in hot locations, like Arizona, Nevada, California and even in the Middle East.
It is possible to replace a metal halide fixture with LED technology. It can be as simple as retrofitting or replacing your existing fixtures.
An investment in LED will have pay backs in many ways. It includes lower energy usage, lower maintenance costs and higher quality of light produced.
This blog post is our second post to one of our most popular posts, “How Many Watts does it take to replace 1000W Metal Halide”. While many of the concepts are the same, there are some important differences between 400W and 1000W Metal Halide.One of the most common questions we get asked is:
“How many LED watts does it take to replace a 400 watt metal halide bulb?” “I just talked to another LED company and they said to use their 150W LED Fixture. How much is your 150W LED Fixture?” “I’m looking to convert my fixtures over to LED High Bay Lights and what wattage should I get?”
This approach is fraught with error. The amount of watts a LED fixture consumes should never be the guide to replace and existing Metal Halide or HPS light. Let us explain…
How many LED Watts does it take to replace a 400 watt metal halide?
Probably the best advice we can give anyone is never buy a LED product based on watts, buy it based on lumens and then figure out how little watts you can use to make those lumens.
What is a lumen?
In simple terms, it’s a measurement of light that basically defines how much light a certain fixture or bulb produces. It is essentially the light you are replacing. Fixtures produce lumens, consume watts, and all the fixtures lumens combined provide a foot candle measurement. When we do a photometric calculation, we take the scientific information associated with that fixture or bulb, insert it into photometric software, and calculate the foot candles for the area. In real terms, a light meter will give you a foot candle reading at the place you are standing. Move close to a light source, the foot candles will rise. Move away, it will fall. The foot candle reading in between 2 fixtures is the collective lumen output of the 2 fixtures distributed to that point where you are standing.
Why does this matter? A lot more than you may think, because it’s all that matters when it comes to replacing old lighting systems with new and improved lighting technology.
When replacing an existing fixture (or entire system), you need to know your lumen output per fixture. Let’s say your metal halide fixtures initially produce 32,000 lumens per 400 watt bulb. So instead of thinking, “I need 400 Watt LED to replace 400 Watt Metal Halide,” you need to be thinking
“I need an LED that can replace 32,000 lumens.”
With this example of 32,000 lumens for a 400 Watt metal halide, that means it is outputting 80 lumens per watt (initially). In the world of lighting in today’s technology world, this isn’t that efficient, with LEDs approaching 200 lumens per watt. However, there are some other factors going on here that you need to be aware.
Understanding Initial lumens and L70
32,000 lumens seems bright. It is. However, bulbs were designed for high initial output because Metal Halide suffers from pretty fast lumen depreciation. It is not uncommon for a metal halide bulb to lost 50% of it’s lumens at half life. Full life for a metal halide bulb is 15,000 hours. That means at 7500 hours of use, it has lost half (or 16,000) of its lumens.
L70 is a term the number of hours before a bulb is performing at 70% of initial lumen output. For metal halide, that calculates to 5,000 hours of use.
You will notice L70 times for LED is spoken in terms of 50,000 and 100,000 hours, not 5,000 hours like it is for Metal Halide bulbs.
Loss of Light due to Reflection
LED light is directional, that means all its light is delivered where it is pointed. It does not need a reflector to collect it and deliver it to where its needed. Conventional light sources are omni-directional and require reflectors to gather the light and focus it to where it is needed. Any reflection of a lumen that is over 1 bounce in the reflector is effectively a loss of that lumen. It has been proven that you can lose up to 30% of the effective lumens in this reflective process.
So if a Metal Halide bulb has 32,000 initial lumens, the loss accounted to reflected lumens drops the lumen output to around 20,000 lumens.
Quality of Lumens – CRI
Color Rendering Index, or CRI, is the best explanation in comparing the quality of light source. Simply said, the higher the quality of light, the less quantity you need. It is not uncommon to have customers tell you that 20,000 lumens of LED appear brighter than 60,000 lumens of other light sources, like HPS.
The basic truth is you need less quantity when you have higher quality.
Photopic vs Scotopic Lumens – How we perceive light versus how a light meter perceive light.
Photopic lumens are lumens that are detected by a device, like a camera or a light meter. It picks up all sources of light that we cannot see, like UV and IR. Scotopic lumens are lumens detected by the human eye. Its how we as people perceive light.
LED produces light within these spectrum’s, which means the light perceived by LED is light that we use. It is rare to see a LED light produce IR or UV spectrum’s. These wavelengths are invisible to people, so they have no value to us from a vision perspective.
It is not uncommon to stand under 2 light sources, one LED and one not, and first read the fc measurement with the light meter of both light sources. And then ask individuals standing near by what light source they think looks brighter. And have the one that looks brighter contradict what the light meter tells us.
We perceive light sources and brightness different, in some cases, than light meters.
Putting This All Together
The basic takeaway from all of this is you need far less LED lumens than metal halide or HPS lumens.
Metal Halide bulbs are very bright out of the box, but not so much even after only 6 months of use.
LED light is directional. The light goes where it is needed. No loss due to reflection.
LED light is high quality light. You need less quantity when you have higher quality.
So how much LED Lumens do you need?
Only a photometric can tell you exactly how much you need. But over almost 10+ years of selling LED lighting, our general rule of thumb is:
Indoors: 15,000 to 25,000 lumens (depends on application and mounting height). You would find these lights in a warehouse, factory, gymnasium, auditorium or swimming pool.
Outdoors: 14,000 to 20,000 lumens (depends on application and mounting height)
By searching for a LED equivalent to a 400 Watt Metal Halide you can easily find fixtures that output at over 100+ lumens / watt. Especially when you go with quality products from reputable companies, you can reach higher than a 150 lumens / watt output. This will allow you to cut your wattage usage per fixture by 2-3 and sometimes 4 times which will prove to save substantial amounts of energy when you start talking about replacing multiple fixtures.
What are my “Replacement Options”?
Replacing can consist of two things: retrofitting or fully replacement. The difference is simple, a retrofit kit is just like replacing the light source (bulb and ballast) in the fixture. On the contrary, full replacement includes replacing the entire fixture including bulb and ballast. Which is best for you? That really depends entirely on your facility, fixtures, needs, and priorities. In general, if your existing fixture shell is good to use and not outdated or falling apart, a retrofit kit will work perfectly. If they are old, outdated, leaking or need replacing: a full replacement is probably the best option.
Are the LEDs in a retrofit kit as good as a LED fixture
Yes. Despite of what you heard or been told, there is no reason to think or believe that a retrofit conversion kit won’t perform or last as long as a new LED fixture. Retrofits don’t always make sense, but they do if you have a significant investment in your fixture or the look of your fixture. Our retrofit kits are warrantied for 10 years, and they have been extensively installed inside a closed sealed fixture in hot locations, like Arizona, Nevada, California and some even in the Middle East.
Keep this in mind: retrofitting is almost always cheaper because it’s easier to do and it’s not as material intensive as a full replacement is (but that is obvious). So if you can retrofit, go with that over a full replacement!
It is possible to replace a metal halide fixture, that of any wattage (30 on up to 1000+), with LED technology. It can be as simple as retrofitting your existing fixtures or a little more work intensive to fully replace, but both will work.
So although it may seem hard, confusing, or expensive: the benefits far surpass of these common scares that people have when making the consideration of upgrading to a new luminary technology. An investment in LED will provide payback in many ways, from less energy usage to higher quality of light that they produce.
This is a common message we try and teach our customers when they call us. For example, it is not uncommon for us to get a call to quote a price on a LED Product, and being told they need a price on a 150W LED Fixture. The most important thing we can do for our customers is to explain LED efficiency. Read this post to discover the right way to pick the right LED product.
1. What are Watts?
Watts are simply a measurement of consuming energy. When you pay the utility bill, the bill represents a charge for the amount of watts, or energy, you used. A 400W Metal Halide Shop Lights consumes 400W of energy. What it doesn’t represent is the amount of light, or lumens, produced. Although, over time, we begin to associate light levels with the bulb being used. So we say “We want the brightness of a 400W MH Bulb”. What we really are discussing is the amount of visible light produced by the bulb which consumes 400W.
2. What are Lumens?
Simply, a lumen is a measurement of visible light. The more lumens you have, the brighter the light will appear. Most companies will tell you three important facts about lumens.
Initial Lumens: how many lumens will the fixture produce brand new
L70 Lumens: how many hours will it take before the fixture produces 70% of the initial lumen value
Lifetime of fixture: this is typically the expected life (before complete failure) of the fixture, or how long you can expect the fixture to operate without the need for maintenance.
3. Understanding Lumens/Watt or Efficacy
The key to this discussion is understanding lumens per watt or efficacy. This is a measurement of how efficiently a light source converts watts into lumens. Old technology like Metal Halide have an efficiency of about 80 lumens per watt. So it takes 400 watts to produce 32,000 lumens.
LED, on the other hand, is significantly more efficient, with levels approaching 200 lumens per watt. For example, we have LED retrofit kits that produce light at 165 lumens per watt, over 2X as efficient as the metal halide bulb it replaces.
However, here’s the catch. Not all LED products have the same efficiency. In fact, the variance can be rather dramatic.
A LED fixture at 100 lm/W needs 200 watts to produce 20,000 lumens
A more efficient LED at 150 lm/W needs only 133 watts to produce 20,000 lumens
So when buying LED, its really important to understand the efficacy of the fixture when comparing products.
4. Putting it all together – how to determine the best LED fixture to consume the least amount of energy.
So lets say you are in the market to replace your existing lighting. Here are the steps to follow.
Determine how many lumens you need. How do you do this? Take a foot candle reading at your location, and determine if that is the right amount of light. (it can be raised or lowered – and now is the time to do this)
Now you know the average foot candles, determine how many lumens you need to produce this amount of light to meet your foot candle requirement. A reputable company, such as MyLEDLightingGuide, will assist you with a photometric and show you, using software, how the light levels could look when you convert to LED.
Pick the fixture with the highest efficacy to produce those lumens. The watts consumed by the fixture is the energy consumption that you will now lower your utility bill to.
5. The Golden Rule: Buy Cheap – Buy Twice
Let’s make one point clear, we are very competitive with our pricing. But we get a lot of customers calling us to fix their cheap LED purchase problems (purchased elsewhere). Those problems consist of lights that have broken or aren’t what they thought they were buying. So we understand, everyone wants a bargain. But be careful of low priced products – its cheap for a reason.
We hear this question all the time. The unfortunate reality is “watts” is the wrong way to shop when you are replacing your existing lighting. You need to be focusing on “lumens”. In the world of LED Lighting, a watt is consumed by the LED product and light is produced, that light is called lumens. Some LED products are better at doing that than other products.
So it is important to understand that not all LED products are equal in terms of how efficient they are at converting watts to lumens. In technical terms, we call this lumens/watt.
So our 100W Retrofit kit at 155 lumens per watt produces 15,550 lumens. In contrast, a competitive retrofit product that uses older LED Chips is designed to run at 97 lumens per watt. This competitive Retrofit kit produces slightly over 13,000 lumens but needs 135W to do produce that amount of light.
So clearly watts is a poor gauge to determine what you would use to replace an existing light source. If a customer called both companies and asked “how many watts do I need to replace 400W Metal Halide”, we would say 100W, they would say 135W.
How is that customer supposed to make a decision? But even then, our 100W produces more lumens than their 135W product.
So when customers ask us how many ‘Watts” do I need to replace an existing light source, we always convert them to lumens.
However, there is one large elephant still left here that we need to talk about. And that is the discussion of efficiency. In the above example, our retrofits produce more light while consuming 35 less watts per unit.
This is important, because this is 35 less watts that you are consuming and paying for on your electricity bill. So efficiency does matter, because it means your electricity bill will be significantly less using the 100W Retrofit kit than our competitors 135W Retrofit kit.
So as with the discussion above, there is a vast difference between LED products being offered on the market today.
Read the specs, and educate yourself on lumens. The less watts you consume saves you money, the more efficient the light is means it will produce more light using less energy than less efficient models.
Should I Buy New fixtures or retrofit my existing Light Fixtures?
This is another interesting question. And over the years, we have seen some pretty interesting answers coming from some of our competitors. Those that sell new fixtures claim new fixtures are the way to go. Those that sell only Retrofit kits claim that retrofitting is the only way to go. Who is the LED Consumer going to believe?
Fortunately, MyLEDLightingGuide sells both new Commercial Lighting Fixtures and hid replacement kits and so we are not biased in helping our customer make this decision. Keep in mind one point as you make your decision. Retrofit Kits are typically less expensive than a brand new fixture because you are not paying for the cost of the fixture. You are also not paying for the disposal of the existing fixture.
We have also heard the stories about how LED performs better in a new fixture than they do if you retrofit an existing fixture. That’s an interesting argument. Fortunately, we have had cases where we have sent both new fixtures and retrofits to customers to “test” the different options. Based on our experience, we have not seen evidence where the new fixture “always” performs better or is preferred over the retrofit solution. In more cases than not, the correct LED solution wins because they are the right solution for their needs.
Also, some “new fixture” vendors would like for you to believe that retrofits do not last long or as long as their new fixtures. Some vendors like to claim that all product coming from overseas are cheap and made poorly. Here is what we believe to be true. Our products are currently in their 6th generation of production. They come with a 10 year warranty.
They are built with brand name LED Chips and Drivers.
Here are some points of discussion you should consider if you are debating whether you should retrofit or replace your existing fixtures.
If your fixtures are in relatively good shape, retrofitting is typically lower cost, all things considered. New fixtures are not cheap, and using your existing fixture will save you money, plus a Retrofit kit is less expensive to ship than a new fixture.
If you have a large investment in your LED Light fixtures, then retrofitting allows you to keep your fixtures but move over to the new technology. A good example of this is area lighting at car dealerships where the pole and light head are an architecturally matching pair. Replacing the head with a non-match led head does not make sense.
If your fixtures are old and deteriorating, then you should replace your fixtures. Our Retrofits are not water proof, and you could damage them if they get wet. The LED Drivers are typically waterproof (look for the IP rating on the label, it needs to say IP65, IP66 or IP67).
There are instances where we would always recommend new fixtures over retrofit. One instance would be for High Masts and most 1000W Metal Halide High Bay applications.
It takes slightly longer to retrofit a fixture than it does to replace it.
You have to account for the disposal of the bulb, ballast and fixture when you replace a fixture and account for the disposal of the bulb and ballast when you retrofit a fixture.
Retrofit solutions perform as well as new fixture solutions.
Retrofit solutions will last as long as new fixtures as long as the Retrofit kit is installed properly.
Regardless of what solution you choose, you need to review the specifications of the LED components.
You should always determine how many lumens you need to replace your existing fixture, NEVER purchase based on watts. Not all LED solutions produce the same lumen per watt output.
Pay special attention to the lumens per watt of a fixture. IT DOES MATTER. A LED product at 135 lumens/watt will consume far less energy than a LED product producing 97 lumens/watt. Not all LED solutions are the same. (remember, always buy on the lumens you need, never on the watts you think you need.)
To calculate lumens per watt, take the total number of lumens a product produces and divide it by the watts it consumes.
Some Lumen Guidelines to Follow
For indoor fixtures
10,000 – 14,000 LED Lumens
15,000 – 25,000 LED Lumens
38,000+ LED Lumens
For outdoor fixtures
7,000 to 10,000 LED Lumens
12,000 to 16,000 LED Lumens
38,000+ LED Lumens
Our most powerful Retrofit kit produces over 50,000 lumens, our most powerful new fixture produces over 117,000 lumens.
We have new LED Lighting fixtures that can replace from 100-1000W HID, we have retrofits that can replace from 100-1000W HID.
Pay special attention to the lumens per watt of the LED fixture or retrofit. IT DOES MATTER. A LED product at 150 lumens/watt will consume far less energy than a LED product producing 97 lumens/watt. Not all LED are the same. (remember, always buy on the lumens you need, never on the watts you think you need.)
To calculate lumens per watt, take the total number of lumens a product produces and divide it by the watts it consumes.
You can get rebates for both new fixtures and Retrofit kits. Make sure they are DLC Qualified. That is the key to getting rebates with your utility company. You can check if a product is DLC Qualified on the DesignLights Consortium website. DLC has rebates for LED Lights.
Rebates with DLC Premium should be higher than rebates with DLC Standard. Your utility company is typically who provides the rebates and sets the rebate amounts. Check their website.
All DLC Products are warrantied for at least 5 years.
All our LED Fixtures and Retrofit Lighting are either UL Listed or ETL Listed.
Replacing the light parts of an existing fixture with the a Retrofit unit will not void the UL/ETL Listing of the fixture.
ETL Listing is the same as UL Listing. They perform the same test, and the certification is the same. The only difference is that the company who performs the test.
The Truth About LED Lumens
Why is it you can replace some lights with more ‘advertised’ lumens with a LED light with less lumens. Here are 4 reasons why you can use less LED lumens to replace traditional HID lights
1. You need less lumens when you have Focused Directional Lumens
LED light is directional, conventional light sources are omni-directional and require reflectors to gather the light and focus it to where it is needed. Any reflection that is over 1 bounce effectively loses the effect of the lumen. It has been proven that you can lose up to 30% of the effective lumens in this process.
2. Quality of Lumens – you need less quantity when you have better quality
This is related to Color Rendering Index, or CRI, and the best explanation is seeing how much better you can see when comparing LED to High Pressure Sodium. It is not uncommon to have customers tell you that 20,000 lumens of LED appear brighter than 60,000 lumens of HPS. The basic truth is you need less quantity when you have higher quality.
3. Photopic and Scotopic Lumens
This has to do with how a camera perceives lumens and how humans perceive lumens. Photopic lumens are lumens that are detected by a device that is similar to a camera. Light meters register photopic lumens. Scotopic lumens are lumens detected by the human eye. LED produces light within these spectrum’s, which means the light perceived by LED is light that we use. It is rare to see a LED light produce IP or UV spectrum. These wavelengths are invisible to people, so they have no value to us from a vision perspective.
The science of scotopic lumens is associated with a factor that allows us to adjust the photopic value to give a true representation of how useful the lumens are. The factor, developed by scientists, is an attempt to level the playing field. The factor is used to adjust the effective value of the lumen, either up or down from the advertised photopic lumen advertised on the package. Some lights, like HPS, have a factor that reduces the lumen amount. LED, on the other hand, typically has a factor > 1.7, which means the lumens it is producing is far more effective to us. Therefore, less lumens is required to do the job.
4. Lumen Degradation
It is not uncommon for HID bulbs to have lost up to 50% of its initial lumens after only 5000 hours of life. Yet these bulbs are rated for 20000 hours. That means the customer is using a bulb that is performing poorly for the next 15000 hours of life. As well, as lumens degrade, so does CRI. And so the “effective lumens” of the light is dropping quickly.
We have been very successful replacing 400W Metal Halide bulbs with our 100W LED Bulb Replacement Kit. The comments we here back is the light is brighter and the area is brighter. It currently produces 15,500 lumens.
Another example is 100W LED LowBay producing 14,000 lumens. This is designed to replace upwards of 400W metal halide. If you have a low bay fixture filled with CFL bulbs or a 250W Metal Halide bulb, this light is going to be a dramatic improvement over what you have. And we have models in either black or white, so it can easily fit into any decor. We can add opaque lenses to hide the LEDs, if that is what you are looking for. L70 life hours exceed 50,000 hrs, compare that to a Metal Halide bulb that is at L50 MyLEDLightingGuide has been in the business of educating and selling LED Lighting since 2008. If you have any questions about our products or LED in general, feel free to contact us or call us at (888) 423-3191