Step 1 - determine Your form of Fluorescent Fixture


In bespeak to calculation your full fixture wattage, you need to know what the wattage is that the existing mechanism you have in place. Over there are many variables, however typically we watch T-12 fluorescent bright in many places. Even if girlfriend are mindful of the you use T-12"s, knowing what form of T-12 fixture is very important. Here are the 3 that we run right into most

Step 2 - What dimension are the Fluorescent Fixtures?

There are mostly 3 sizes of fluorescent fixtures; they are:

2" x 2" - frequently a square form of fixture. Found most regularly in office situations. This layout fixture has actually a U-shape bulb. 2" x 4" - rectangular fixtures the are generally used as drop in"s in office situations. They are occasionally used in manufacturing atmospheres as direct lighting over a particular area.These fixtures have 4" bulbs and also most have actually 3-4 bulbs per fixture. 8" - Long and also narrow is the best description the these varieties of fixtures. Typically seen in 2 - 8" pear configurations. (Quick Tip: If you room unsure of what kind of fixture you have, T-12, T-8 or T-5, take a look in your storage room, look at the pear or box, or ask her maintenance employee what form of bulbs they room using)

Step 3 - recognize the quantity of every Fluorescent Fixture

Once girlfriend have figured out the type of fixture you have in your facility(you might have countless types) total up the variety of each type in each area. If you have a the majority of fixtures come count, obtain some help. Friend can quickly get lost in your count walking approximately looking increase in the ceiling (oh ya, don"t trip on noþeles either!)

Now that you have your fixture count, girlfriend are all set to calculation your full wattage.

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Step 4 - determine the Wattage for Each form of Fluorescent Fixture

There are a couple of different ways to number out the wattage the the fixtures in your facility. One is facility and the various other is not so complicated.


If girlfriend really want to be exact and also have numerous time on your hands, then you could theoretically go to each and every fixture to discover out what type of ballast you have. This would be much more exact together then you could determine your ballast factor, form of ballast and also other appropriate information.

This way would require a remarkable amount the time and also effort i beg your pardon isn"t necessary because companies like general Electric and also most utilities take on averages because that calculations.

Not therefore Complicated:

You don"t need to be specific when determining your fixture wattage. Girlfriend should be able to determine indigenous a street what the form of fixture is and also then identify the wattage. From over there you can use averages like the ones that us use once doing one energy efficiency assessment.

Here room the fixture wattages the we commonly use:

89 watt - 2"x2" -U-shape Lamp

140 watt - 2"x4"(3 Lamp)

178 watt - 2"x4"(4 Lamp)

158 watts - 8"(2 Lamp)

178 watts - 8"(4 - 4" Lamps)

By using the averages, we room able to acquire a an excellent comparison against newer technologies with reduced fixture wattages.

Step 5 - main point Your quantity of Fixtures by the Wattage of her Existing Fixture.

Let"s say you have actually 100 fixtures and they space 8" - 2 bulb T-12"s:

100 fixtures x 158 watts = 15,800 full System watts (Assuming this is the only kind of fixture girlfriend have...)

Want one an ext complicated?

Okay, how about you have actually an office v (20) 2" x 4" 4 bulb T-12"s, a job-related area through (78) 8" - 2 pear T-12"s:

20 fixtures x 178 watt = 3,560 complete System Watts

78 fixtures x 158 watts = 12,234 complete System Watts

3,560 watt + 12,234 watt = 15,884 total System Watts

Step 6- Forget the Calculations and also Call Hovey Electric.....

If her still confused about all the this, here are some resources for you to consider:

See my article "Watts" a Watt? If you want to see exactly how to take this calculation further and calculate your power savings from a brand-new system upgrade...or...


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If friend would prefer to learn an ext about the benefits of energy performance for her business, justdownload our ebook, by clicking on the book below. It"s complimentary and available right away, acquire your copy....

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Topics: t5 retrofit, t5 vs. T8, power savings, calculate energy savings, energy efficiency, t8 vs. T5, calculating wattage, t8 fixtures, wattage