Fluorescent vs. Metal Halide Lamps for High Bay Lighting

Hello Donald,

The marketing guys at the fluorescent lighting makers are pushing operating costs ($ per lumen) over maintenance/replacement costs. They are not real interested in making them easier to install unless you want to go with a more expensive lamp (i.e. High Output). After all, if all 4 pins of a fluorescent lamp do not make good contact with the socket then the resultant short life is the fault of the installer. Single pin Instant Start lamps are easier to install correctly but they have a slightly shorter life expectancy. Any way you look at it, the linear fluorescent lamps are still a bit more cumbersome to install because they are so bulky in at least one dimension.

As for marketing, they are promising long life expectancies on the order of 30,000+ hours. When you calculate the replacement cost (including labor) divided by the life expectancy, guess who wins! You have to remember that bean counters are in charge of financial (not logical) decisions. Most of those guys will have new jobs anyway by the time those lamps are gone. And the bean counters almost never get involved in the finer details of claims. But if you look closer at the manufacturers claims, you will notice that they only expect half of any population of lamps to make it to 30,000 hours. So, it begs the question, who in their right mind is going to let half of their lamps burn out when it so negatively affects the appearance in a "store or office"?

Finally, it comes down to numbers and who can deliver the best line of BS. I find it kind of convenient to have some inherent failure modes built in due to improper installation. What better way to increase repeat customer sales and blame the failures on customer error at the same time??? So many suckers, and so little time...

Thanks for that "Broader Spectrum" of understanding.. I figured as much...

What I see happening is actually a Good thing, for my business, as we are stressing LED as much as possible, as even in this down market, we are doing pretty well with those sales..

For instance:

We just did a wax museum with 100 pcs of our 3X1 watt par16 120v 5000K screw in lamps.

I haven't been down there since they installed them, but I guess the owner loves them.

They say it makes O'Bamas eyes shine that glowing brown, and of course doesn't change his wax skin tint, as NO ultra violtet..

Not to mention they consume only 3 watts. (Instead of the Par20 Halogen 5o watts) and are ECO friendly NO Mercury.

Oh well, let the bean counters rule on this fluorescent deal, I'll just wait until the really high Power LED's get cheaper, then sell the hell out out em.. :o)

Donald

GA Odd Joe

clearly another case of buyer beware... most people forget that the salesman they are talking to is in the business of making money. They do this firstly by selling you a product and secondly by providing you with replacement parts for that product, the more frequently you have to replace lamps or ballasts the more frequently you're going to stop in and pay that salesman's salary... Why would you listen to anything they have to say?

People understand the concept of getting a second opinion when their doctor tells them they need an expensive procedure, but whatever the salesman working the lighting aisle at home depot says must be true, they had a 4 hour training session on the subject which clearly makes them an expert...

"

LED Lighting Costs

When considering a new technology, cost is naturally the main topic of interest. Not only should one consider up-front costs, but also the accumulative operational costs associated with powering a lighting system. It is very important for business owners to understand that investing in LED lighting does not result in immediate savings, but does promote significant savings over time. A specific metal halide bulb, commonly used in gas station canopy lighting, dissipates 400 watts of total power. A custom LED product designed to substitute this metal halide, dissipates an amazing 60 watts of total power. Over an extended period, it is obvious how the 60 watt LED product will result in dramatic energy savings.

Metal Halide Operation

Metal halides contain a mixture of gasses within the bulb. As the device operates, the internal temperature and pressure begins to increase. Unlike metal halides, LED lights do not feature a gas, operating under extreme pressures, at very high temperatures. Instead, the LED lights contain a solid state lighting element, eliminating several risk factors associated with high pressure gases. Solid state lighting has advanced dramatically over the past several years, and has become the industry standard for a variety of lighting applications.

Lighting Start-Up and Cool-Down

During initial start-up, the metal halide will fail to operate at the maximum luminous output. The pressure and temperature within the interior arc chamber may require up to five minutes to achieve the necessary state for optimal performance. During this warm-up period, the metal halide may exhibit numerous colors as a result of vaporization occurring within the arc chamber. In the event of a brief power failure, the arc will extinguish. A cooling period as long as 12 minutes may be required prior to restart. Unlike the metal halide, LED lights respond instantly, and do not require a warm-up period. In the event of a momentary power failure, the LEDs will resume normal operation the moment that power is restored.

Metal Halide and LED Life Span

A specific metal halide features a 20,000 hour life, according to the manufacturer's data sheets. Improper bulb orientation can actually reduce the life by 5,000 hours. Near the end of life, the bulb will begin to exhibit "cycling". As the lamp ages, the required voltage increases beyond the available source voltage. With increasing internal temperature, the lamp will fail. After a brief cooling period, the lamp will re-start. This process will then repeat on a continuing basis. Aging LED lights do not exhibit similar behavior! An LED fixture designed to replace metal halides in gas station canopies, can provide up to, or in excess of 50,000 hours of life. The LED lights may remain operational for as long as 100,000 hours, at a decreased luminous output.

LED Lighting Heat Dissipation

LED lights generate significantly less heat when compared to the metal halide bulb. Not only do the LEDs generate less heat, but they also dissipate their thermal energy back into the mounting fixture. Most traditional light bulbs tend to dissipate heat from the front of the bulb, and out into the surrounding atmosphere. This can make thermal management a challenge in certain applications where the direction of heat dissipation becomes critical.

LED Beam Angle

Due to the directional characteristics of traditional metal halides, the bulb produces mass amounts of wasted light from the top and sides of the lens. Not only does this result in a lower system efficiency, but also contributes to environmental "light pollution". In rural areas, metal halides can illuminate the night sky, causing an eye-sore for nearby residents. However, LED lights feature superior directional characteristics, and can dramatically reduce night sky pollution. The narrow beam angle featured on many LED lights provides illumination within the intended areas only. Not only does this reduce light pollution, but also promotes higher overall system efficiency." (referrenced from http://www.lunaraccents.com/applications-metal-halide-lights.html)

Most flourescent bulbs that I have seen installed in manufacturing facilities have an average 50,000 hour life span, based on manufacturer data sheets. Both types of lighting go through the same testing techniques to determine life span.

Going with your converting to 10, 6 lamp T8 flourescent fixtures (my spreadsheet doesn't have the 8 lamp), a company would save $30,848 per year over 10, 400W metal halide fixtures and the project would have a payback period of 0.9 years. This assumes $0.08 per kWh and $75 per hour labor for installation. This is in Indiana which has one of the lowest electricity rates in the US.

I don't see why they wouldn't switch. The stores that you have visited may have just installed the wrong light fixtures for their purpose or don't maintain them properly.

You said:

Going with your converting to 10, 6 lamp T8 flourescent fixtures (my spreadsheet doesn't have the 8 lamp), a company would save $30,848 per year over 10, 400W metal halide fixtures and the project would have a payback period of 0.9 years. This assumes $0.08 per kWh and $75 per hour labor for installation. This is in Indiana which has one of the lowest electricity rates in the US.

Kindly prove to me how you came up with this figure.

Donald

I have a spreadsheet that calculates it for me. It is on loan from Granger lighting.

You did catch a mistake. The spreadsheet was set up for two buildings and I forgot to remove the other building.

$1,713.25 is certainly not anywhere near $30,848, thank you for the clarification.. That is exactly what I figured as well with my calculator..but I didn't want to insult you.

Also, believe it or not, LED's DO generate quite a bit of heat. That's why all the newer High power bulbs all have monster heat sinks around them, to dissipate it.. Also, the brighter the LED product, the hotter it is, and the shorter the life expectancy. Forget 100,000 hours, as that is just a myth.

Also, just like every other light source, LED's begin to lose light the minute you begin to use them.. So, if a 5mm 60 pc LED Light bulb is rated at 100,000 hours, most of your useful light from it, will be gone at approx 50,000 hours..

I have even seen some figures of only 10,000 hours on some LED.

However, it does appear that great energy savings can be had by using LED, and we are all waiting for the Big Boys to mass produce so we can afford to purchase them in quantity..

Also, in your line of work, they should make you happy, as the heavy metals are mostly non-existent, and at worst, in very small amounts.

Cheers,

Donald

You said,

"Most fluorescent bulbs that I have seen installed in manufacturing facilities have an average 50,000 hour life span, based on manufacturer data sheets. "

I've only been out of the R&D world of fluorescent lighting for a couple of years, but I can hardly believe a claim of 50,000 hours. I think you may be referring to a marketing scheme of selling a promise that includes a "free" replacement of the lamps about half way through the 50,000 hour period. Of course, nothing is really "free". You have to pay a premium for this extended life, and you may be required to leave these lamps on 24 hours a day.

The fluorescent industry feels very threatened, as they should, by the LED industry. The thing that limits how long a fluorescent lamp will last is retention of an emitter compound on the electrode (usually a tungsten coil). And, as in most lamp products, the longer they operate, the dimmer they become due to deposits of various materials near the electrodes, commonly referred to as end darkening. All of this is a function of the interaction of plasma and temperature at the interface between gas and solid materials inside the lamp. Operating stability is your friend when it comes to questions about life. The challenge is to stay above the operating zone where sputtering occurs (due to cold emitter) but below the zone where evaporation occurs (due to excessive emitter and electrode heating). Starting a fluorescent lamp drives the temperature from ambient to about 1000°C in about 100 mSec unless it fails to start. Then it does it several times. Thermal cycling is tough on everything in nature.

Lastly, it takes so long to get real life expectancy results that many of these numbers are estimated. And where I worked they failed to really analyze the cause of "end of life" failures to determine a true cause and effect. The types of failures included glass failures, electrode failures, emitter depletion, ballast failures, and other sources of contamination. So, there are lots of excuses and lots of promises. But the predictions include the eventual elimination of many of the common forms of lighting products in favor of LED or other solid state lighting. It's just a matter of time.

I work with manufacturer's making all types of products. Almost every single one does have their lights on 24/7. In those facilities that I have visited (over 25 in the last year alone), I have seen more metal halide lights either out or not operating properly than I have seen with the flourescents. The companies that had already switched to flourescents were very happy with them and the reduced maintenance required for the lights.

By the way, my specialty is not lighting. It is pollution prevention. I look at all aspects of every change that I suggest. If someone can produce some actual numbers from their plant to include disposal costs and show that it is not an adverse environment that shortens the lifespan of the lights (chrome platers with indoor air quality problems are a prime example), I would be able to adjust my calcs.