I am a General Manager for a company that has multiple large buildings. I have had it expressed to me by one of my investors that removing one of the two flourecent (32 Watt) bulbs from the unit will reduce cost by $30.00 a bulb a year! My simple understanding is that the ballast will run the same charge regardless if there are one or two bulbs in the unit? Is this correct? Will there be a marked cost improvement by reducing the unit by one bulb? Help me out with this one please.

Thanks

Remember, OSHA has lighting standards not to mention NEC Code requirements.

And in many cases, one bulb in a two bulb ballast won't even turn on.

Most electronic ballasts will start and operate on just one bulb. You won't cut the operating costs in half, since the ballast itself still consumes energy with or without the second bulb. But... can you afford the light loss by removing the bulb? Consider a retro-fit for the fixture that will center the bulb and install a reflector if light loss is an issue. Are these individual fixtures or strip lighting?

I suggest you do a search for "delamping".

Here are few for your review:

http://www.lightingdesignlab.com/ldlnews/delamping_ml.pdf

Lighting & wiring equipment engineering - Delamping & Ballast Damage (http://www.eng-tips.com/viewthread.cfm?qid=69045&page=2)

Saving Energy With Proper Fluorescent Lighting (http://ecmweb.com/mag/electric_saving_energy_proper/)

While delamping a 32 watt T8 fixture will save a very small amount of energy, I do not recommend it as a standard practice.

One reason Don refers to. Light levels will be affected. Depending on the task being performed, could affect production and/or the comfort level of the occupants.

Bi-level switching helps to save energy if the light levels are not critical.

Only certain T8 ballasts allow for 1 or 2 lamp operation, some do not. So there is a operational and UL issue if your do not allow for multiple lamp operation.

There are now on the market 25, 28 and 30 watt lamps designed to run on a 32 watt ballast. Consult with a lighting designer for the options open to you rather than just delamping.

And if you really want to save some energy switch to t8 LED lighting. T8 LED Fluorescent Tube, LED Tube, Fluorescent Replacement, LED Replacement Tube, EarthLED DirectLED FL Series, LED Fluorescent Tubes (http://www.earthled.com/DirectLED-t8-fluorescent-led-tube-replacement.html?gclid=CNzpicjv3J8CFQOfnAodGUUKGw)

I am having a difficult time selling $6.00 T5 fluorescent light bulbs, let alone $80.00 LED light bulbs in this economy, no matter how much energy they can save.

I have managed to sell a few LED specialty fixtures, floods and canopy type fixtures. I have yet to see a LED with a decent color temperature of 4100 Degree Kelvin CCT, let alone 35K. To illustrate, these are rated at 75 CRI, which is not very good, and I suspect a bit inflated at that.


None of the answers, including mine, really addressed the original question, so let me see what I can do.

Attached link is a data sheet for a very typical 120 volt 1 or 2 lamp T8 ballast.

http://www.advance.philips.com/eCatalog/out/6206896651.pdf

Assuming the typical 32 watt lamp, it lists the input wattage of two lamps at 58 watts, and one lamp at 38 watts, a savings of 20 watts per fixture if one lamp is removed.

Assuming the following variables to arrive at projected cost savings:

500- 2 lamp 32 watt T8 fixtures, one lamp removed saves 20 watts per fixture, for a total 10,000 watts saved.
12 hours per day, 5 days per week, 52 weeks per year= 3120 hours per year hours of operation
$0.10 per kilo-watthour cost of energy

Based on this data, removing 500 lamps would save $3,120.00 per year, or $6.24 per fixture/lamp per year.

While you may save $3,000 per year, you also lost half of the amount of lighting. I can tweak that amount by doing the BF and BEF calcs, but the amount of light lost would still be close to half.

And while I do agree that most spaces are overlighted, I doubt these spaces could function properly with half the light.

I need to caution you or anyone to just rely on delamping to save energy.

Proper lighting design is very complicated and will always consider proper light levels and energy costs. Of course, a lighting system with optimum light levels at the best energy savings will not always be the cheapest initial capitalized cost.

Once a reasonable light level is decided upon (usually guessed at), often the cheapest fixture is used often with mismatched lamp/ballast combinations, or the cheapest lamp or ballast available, most times more fixtures are added. Combined with too many fixtures of not the most efficient lamps/ballasts often results in higher energy costs.

I do hope I have convinced you to not just arbitrarily remove lamps to save energy, and to look for other more practical options.