magnetic vs. electronic balast.

[wasabiian]

Question: If I replace a fixture that has 2-13 watt CFL's and a magnetic balast with a like fixture (2-13 watt CFL's) but with an electronic balast. how much energy will I save the customer in watts. I have been pouring over catalogs and the internet and im not getting a good answer. apparently the electronic ballasted fixture is energy star rated but the magnetic balasted ones are not?

I have 26 exit lights that have 1-9w cfl magnetic balast, if I replace them with a 2w led exit light, they would save 80% right?

and there are 21 button style fixtures with 2-9w cfl mag bal, if I change them out with an electronic balast is there any savings? how much?

I would appreciate some knowledgable help.

 

[broadgage]

At a very rough guide, the smaller electronic ballasts will save two or three watts per lamp, possibly four watts.
Exact figures can only be obtained from the supplier.

Lamps are slightly more efficient on electronic ballasts, and therefore some such ballasts slightly under run the lamp in order to give the same light output, as would have been achieved on a magnetic ballast.

For example a 13 watt lamp on a magnetic ballast may drive the lamp at exactly 13 watts, and have 3 watts loss in the ballast, for a total use of 16 watts.

An electronic ballast might drive the lamp at 12 watts, with losses of 1 watt, giving a total of 13 watts, and a saving of 3 watts.

If a twin electronic ballast is used the savings may be greater, for example it might drive each lamp at 12 watts, have losses still of only 1 watt, for a total of 25 watts. Thats a saving of 7 watts over a pair of single magnetic ballasts.

Be aware though that twin lamp luminaires are sometimes specified for reliability, to avoid darkness if a lamp fails.
With some twin electronic ballasts, failure of one lamp will extinguish both, thereby rendering a twin lamp luminare a bit pointless.

Lamp life is normally increased by use of electronic ballasts.

If the existing installation is in good working order, then I doubt that the capital cost of renewal would be justified by the relativly small savings.

If however ballasts or the complete fixture requires replacement in any case, then I would urge the use of electronic ballasts.

 

[wasabiian]

Thanks for the reply,
A 13w cfl w/ mag ballast draws 15watts, while a 13w cfl w/ an electronic ballast draws 13 watts. According to my PUD changing out cfl's to LED's doesnt meet thier cost/benefit ratio. even though we would be saving in excess of 80%.

 

[drive1968]

I had to do a similar change in a building I was working on. I ran a test by changing out just one of the fixtures before I decided to change out all the rest. I then tested the watts being drawn compared to the old fixture. It saved about 40% of the energy, so we decided to go ahead and do the rest.