Maintenance Cost Comparison:400 Watt Metal Halide vs.Fluorescent T5

Posted by Dave VanTol on Fri, Feb 03, 2012 @ 13:02 PM

Have You Calculated The Cost Of A 400 Watt Metal Halide Fixture vs A Fluorescent T5?....If not, you should....

I'm not going to talk about how efficient fluorescent T5 lighting is, or how terrible metal halide is, I don't have to! You already know that....or if you didn't find out, just click here.

What I would like to focus on is maintenance.

It's very common for this item to be overlooked when thinking when thinking about lighting, I mean if a light goes out you just put a new lamp in right?....no big deal.

How Often Do You Re-Lamp Your Facility?

Have you ever took time to think about how much it costs to re-lamp?

Not how much it costs when you flip the switch.....I'm talking about what it to maintain the light fixture once it has been installed.

Lets look at an example.

Let's say we have a medium sized manufacturing facility.  In the warehouse work area, there are 60 - 400 watt metal halide fixtures.  The lights are lit up about 4015 hours on an annual basis.

Rated lamp life:

400 watt metal halide lamp life = 18-20,000 hrs.

Fluorescent T5 lamp life = 35,000 hrs.

I need to mention right now that the 400 watt metal halide light output diminishes significantly with use. In fact, a 400 watt metal halide bulb will be 70% less bright in 3 years as the day you installed it. 

Sort of like a new car, drive it off the lot new and when you bring it back in 3 years, it is only worth 30%.  The light from a 400 watt metal halide will never be as bright as the day you put a new bulb in. 

At 8-9,000 hours, or roughly 50% of the rated life of the bulb, you are only getting about 60% of the light output when new.

Because of the reduction in lumen output, you realistically should replace the lamps every 2-3 years.....even though the lamp still works.  While it still works, in reality, the lamp is not as bright as it was on day one.  This is called lumen depreciation.

One important fact to consider: Even when the 400 watt metal halide is giving you 50% of the light due to lumen depreciation, you are still paying the same for the electricity powering the fixture. 

In other words your paying for full light output and in return getting 50%. If your going to pay for 400 watts of light at least my scenario will give you that most of the time.

What Is The Difference In Maintenance Savings?

bulb-life-expectancyLamp life expectancy for our example:

So with 4015 hrs of annual usage our fluorescent T5 lamps will go roughly 8 years before needing to be changed.

(35,000 hour lamp life/4,015 hours annual use = 8.7 years life expectancy)

Our 400 watt metal halide will last roughly 5 years

(20,000 hour lamp life/4,015 hours annual use = 4.98 years life expectancy)

But wait?

Isn't the light output diminished 60% at 9,000 hrs? Yep...sure is. So at 12,000 hrs I'm only getting 50% of the light I should?

If we replace the lamps every 12,000 hrs, thats every 3 years.

Let's Look At The Cost Of Re-Lamping

Cost of lamp and ballast:

400 watt metal halide lamp = $17.00metal halide lamp

400 watt metal halide ballast kit = $80.00

So every 3 years we will spend $1,020 on lamps.

(60 replacement lamps X $17 per light = $1020 for replacement bulbs)

We replace ballast and capacitor when re-lamping:

Ballasts usually last a long time.....the capacitors however seem to fail at around 3 to 3 1/2 yrs.

Yes you can replace just the capacitor, and I have before.....only to get called back 2 weeks later because the ballast died.

Funny thing is, customers never remember you saved them money by replacing the capacitor. 

What they remember is 2 weeks ago you said you fixed it and now your back because it's broke again.  We don't like unhappy customers, so as a rule I change out the ballast and capacitor at the same time. 

(60 fixtures X $80 per ballast kit = $4800 for ballast kit)

So the combined cost of the lamps and ballast kits equal:

($1020 for lamps + $4800 for ballast kits = $5,820.00 every 3-3 1/2 yrs)

The fluorescent T5 fixture will last almost 9 years at this usage.

How many times do you have to re-lamp 400WMH before400-watt-metal-halide-calculating-the-cost-versus-fluorescent-t5 re-lamp of T5?

You will go through lamps and ballasts 3 times before I need to think about touching the T5 fixture.

(9 years before maintenance fluorescent T5 / 3 years before maintenance of 400 watt metal halide = 3 times, you will have to maintain the 400 watt metal halide 3 times)

($5,820 materials X 3 years = $17,460.00 in materials)

What about labor and equipment?

I purposely did not include labor, this is just materials.  Business owners usually have someone to do the maintenance.  There is a cost to that.  We did the calculations separate, so you could make the choice.  

Some places have there own lifts and electricians, others hire it out.

For our example, I will use a very conservative cost for labor, $4,000.

We need to figure a lift for 1 week, $675

($4000 labor cost + $675 lift rental = $4865 for labor and equipment)

Assuming you want to maintain your lighting levels, you will have to do this 3 times with the 400 watt metal halide vs the fluorescent t5. 

($4865 x 3 times you will need to maintain the fixtures= $14,025 labor/equipment)

Lots of numbers, how do we put it together?

Well it took us awhile to get here, let's add up all the numbers to see how much it will cost you to maintain the 400 watt metal halide vs the fluorescent t5:

($17,460 in materials + $14,025 labor/equipment = $31,485 to maintain 60 fixtures over a 9 year period)

Cost to maintain each fixture

So if you maintain your 400 watt metal halide correctly, over a 9-10 year period, operating the lights at 4,015 hours per year here is what it will cost you per fixture:

Just Material;

($17,460 materials / 60 fixtures = $291 in materials to maintain the lights)

 or materials and labor;

($31,485 materials,labor/equipment / 60 fixtures = $524.75 each to maintain 60 400 watt metal halide)

Remember, $524.75 is the cost to MAINTAIN the fixture; this has nothing to do with the initial cost (if you are installing them new) or the cost of electricity to power these things. 

calculate-cost-of-400-watt-metal-halide-before-installingThere Is A Real Cost To Lighting Maintenance

The numbers above are not exact, but the you get the idea.  There is a cost of maintaining 400 watt metal halides.  Few businesses actually take the time to figure it out. 

Most businesses don't change the lamps when they need to, but if you are comparing the light output between the 2 fixtures, you have to factor in the change out every 3 years. 

Look Deeper, There Is A Reason Why 400 Watt Metal Halide Is Cheaper

Calculate all of the costs when making a lighting decision for your business. 

Architects, Engineers and Designers are STILL specifying the 400 watt metal halide fixture, so you need all the facts before you make the decision. 

Afterall, you will be the one paying for maintaining the fixtures, not the Architect, Engineers or Designers. 

There's a better solution

Contact us today and let us show you how you can cut maintenance, cut energy costs, and put more money into your business instead of giving it to the power company or to learn more about energy efficiency, download our Free E-book.  We cover all the benefits owners can achieve with energy efficiency.  Get your copy now.

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How much do you think it costs to maintain your lighting?

Who maintains your lighting for your business?

Hovey Electric provides energy efficicient lighting consulting, design, layout, construction,project management services and trains business owners how to do their own commercial energy audit. 

This article was written by Dave VanTol and edited by Jimmy Hovey, MBA

Topics: fluorescent t5, metal halide vs fluorescent, 400 watt metal halide