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Old 12-24-17, 09:47 AM   #1
oil pan 4
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Default LED versus T5 efficiency

I went to look up LED versus T5 efficiency. It turns out LED beats up older technology like T12 and T8 and takes its lunch money. That's comparing 120v powered LED to T8, not ballast powered T8 LED replacements (these things add together the inefficiency of a ballast plus the inefficiency of LED power supply running off ludicrous high voltage). Turns out stepping up 120v AC power to a few hundred volts to power a tube, then stepping it back down to low voltage DC to power an LED isn't that efficient.
That shouldn't really surprise anyone.

After reading around I found that LEDs don't really offer any efficiency gain over T5. For overall system efficiency LED comes in anywhere from 70 to 100 lumens per watt.
T5 is consistantly 96 to 111 lumens per watt depending on the tube length and ballast.
A big part of the problem is all the junk coming over from china. The LEDs have cheap inefficient power supplies and their lumen output number is what ever they decide to stamp on the box to move product. LED light fixtures should easily exceed T5 efficiency by a lot but no one wants to pay for the newest generation of super efficient white LEDs and high efficiency power supplies, so only cheap junk gets manufactured.

I became interested in the subject when I got ahold of a bunch of free industrial grade, wash down rated high output T5 fixtures. I just assumed that LED light fixtures were super high efficiency and that even the new generation of T5 were outdated and inefficient. Boy was I surprised to find recent data saying in a lot cases LED can be less efficient than T5.

Also any advance in tech that improves efficiency of a power supply for a LED, would also in theory be able improve efficiency of a florescent ballast too. So that playing field is pretty much even, any improvements would be on the LED tech it's self.

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