Thinking about converting to LED? Not sure if the benefits of the conversion outweigh the cost of conversion? We put this post together to help you work through the costs and benefits of making the conversion.
1. How much money will you save when you convert to LED?
Lets take a practical example. You have a 400 Watt Metal Halide fixture. The bulb consumes 400 watts. The fixtures ballast consumes an additional 50 to 60 watts (ballast draw). For purpose of this discussion, we will limit this fixtures total electrical consumption to 455 Watts.
You want to convert to LED. What would be the reduced consumption? If you understand LED, then you will realize that if you buy a more efficient product, it will reduce energy consumption even more. For example, of you decide you need 20,000 LED lumens to replace your 400 Watt Metal Halide fixture, then you need to see how efficiently the fixture produces 20,000 lumens. At 100 lumens per watt, you need 200 LED Watts. At 200 lumens per watt, you need 100 LED Watts. The more efficient product will be more expensive, but the payback will be much greater over the life of the product. So its important to understand what you are buying.
But what are the savings? Lets use some real numbers. Lets assume the 400W Metal Halide fixture is a parking lot lights. Its on every night for an average of 12 hours a day, We will compare it to a LED fixture consuming 100 Watts producing 15,500 lumens (at 155 lumens per watt)
The 400 Watts Metal Halide fixture consumes 455 Watts X 12 hours a day = 5,460 watts per night (or 5.46 kilowatts)
The 100 Watts LED Fixture consumes 100 Watts X 12 hours a day = 1200 watts per night (or 1.2 kilowatts)
Over a year, these two same fixtures consume
400 Watt Metal Halide: 1992.9 kilowatts
100 Watts LED: 438 kilowatts
If your total cost of electricity is .12 kw/h
The cost of operating the 400 Watt Metal Halide Fixture is: $239.14 per year
The cost of operating the 100 Watt LED Fixtures is: $52.56 per year
If your facility had 100 fixtures
Your 400 Watt Metal Halide Fixtures would cost you $23,914.00 on your utility bill
Converting to the 100 Watt LED Fixtures would cost you $5,256.00 on your utility bill
That’s a savings of $18,658.00 per year
2. How LED can reduce your maintenance costs?
We’ve all heard that LED’s will lower your electrical use. And maybe you’ve heard it will reduce your maintenance costs? There are a few factors that add to the cost of maintaining your lighting
the cost of the lights and ballasts
the labor cost associated with changing the lights
the equipment cost, if any, to perform the maintenance
LEDs lifespan is typically longer than traditional light sources. And in some cases much longer. But lets discuss real life span versus another measurement you’ve seen, L70.
What is L70?
L70 is a measurement of lumen degradation. It indicates how long a LED product will run until it achieves 70% of the initial lumen output. What this is not is lifespan of the LED product, or the life of the LED Driver. The light will still continue to work after L70. Therefore, L70 hours is not a good indicator of real life or time between maintenance.
What is real LED Life?
Real life is an indication of how long the LEDs will stay lit or how long the LED driver will operate before it stops operating. Assuming a normal operating environment, a LED driver will last upwards of 50,000 to 65,000 hours. If you run your lights 12 hours a day, every day of the year, that is well over 10 years of expected life.
If the L70 for your LEDs is 100,000 hours, you can expect the LED driver to fail before the LEDs have lost 30% of its initial lumens.
If the LED driver stops operating, you can replace it just like you would a metal halide ballast.
Comparing LEDs to Metal Halide Bulbs
If the LED diodes have a L70 of 100,000 hours, its safe to say it will be a long time before you replace the LEDs.
Metal Halide bulbs are not so lucky. Their lifespan is around 15,000 hours. In fact, their L50 is about at 1/2 life. So you could even debate the useful period of a Metal Halide bulb ends well before the bulb stops operating. But lets say you only replace bulbs when they completely stop working. During the life of the LED fixture (or operating life of the LED driver), you will have performed 4 bulb changes and maybe 1 ballast change. Maybe you do the ballast change at the same time as one of the ballast changes.
Let’s add up the costs of maintenance costs of Metal Halide versus LED
The cost of 4 metal halide bulbs and possibly 1 Metal Halide Ballast
The cost of labor associated with these bulb and ballast changes. These costs go up when the bulbs are mounted above the height that can be reached safely with a step ladder
The cost of equipment if the lights are installed above the height of a step ladder
3. The intrinsic value of higher quality light
LED light is thought of as high quality light. But what is high quality light and how can you measure the quality?
Color Rendering Index, or CRI, is a measurement of the quality of any light source. Its a scale of 0 to 100. Sunlight is considered the best light source, and it has a score of 100. CRI is a reflection of how accurately colors are represented under a light source.
So what will people notice under a high CRI light source versus a lesser quality CRI light source? The colors will be appear brighter, more vibrant and less gray. Colors will “pop”.
There are real world examples of low quality lights in our world today. High Pressure Sodium lights, those “yellow” lights we see lighting up our neighborhood streets, have a very low CRI, typically around 25. You can see it for yourself. Everything appears to be brown or yellow under High Pressure Sodium lights. Its why you will never see one at a car dealership.
So high quality lighting is synonymous to retail environments. Retailers want to put their best foot forward at all times, to make their products look amazing. So high CRI lights are imperative – because good looking products sell. And if you owned a car dealership, wouldn’t you want your product to shine?
LEDs typically are offered at 70 CRI, but you can actually purchase 98 CRI if that is important to you. These options make LED a good option for retail and commercial lighting.
4. High Quality LED Light creates a safe environment
Retailers and commercial customers know that if their parking lot is bright and well lit, customers feel safe and are more likely to stop there are night. And customer traffic = customer sales.
LEDs are bright. They can be as bright as any metal halide bulb on the market today. They also maintain their brightness much longer than Metal Halide. To maintain a safe bright environment with Metal Halide, you might be changing out bulbs well before end of life.
That is why High Quality shopping centers have well lit parking lots. And you will never find High Pressure Sodium in these environments.
With LED, you get a combination of
bright high lumen lighting
high quality light starting at 70 CRI and higher
well distributed light with the addition of lighting optics
What’s the cost of having your customers shop at your competitors store?
5. Cost of Recycling Old HID and Fluorescent bulbs
The problem with old bulb technology is they need mercury to function. The mercury is in the form of a powder. In most places in the USA, it is against the law to throw away dead fluorescent and HID bulbs in the garbage. It is an environmental as well as health risk.
Having mercury released from broken bulbs enter our ground water contaminates the water supply. It poisons fish. This is the food we eat and drink.
And if you’re still not convinced this is a serious issue, here’s what the EPA says to do if you’re in a building and a light bulb containing mercury breaks
Get people and pets out of the room.
Air out the room for at least 10 minutes, and preferably several hours.
Shut off the air-conditioning or heating system.
Wipe up the broken glass and powder, seal them in a container and dispose of them.
Check with your local government about disposal requirements. Some communities require that trashed fluorescent bulbs (broken or unbroken) be taken to a local recycling center.
Recycling bulbs is not free. But it is necessary.
The good news? There is no mercury in LED. So there are no costs associated to recycling a LED product after end of life.
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.