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Thread: Led tubes

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    Led tubes

    Is there much energy savings in just changing the tubes in a fluorescent fixture to LED? Unlike the fixtures that are straight line voltage (120-277) LED, the ballast is still functioning in the old fixture.

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    Quote Originally Posted by nizak View Post
    Is there much energy savings in just changing the tubes in a fluorescent fixture to LED? Unlike the fixtures that are straight line voltage (120-277) LED, the ballast is still functioning in the old fixture.
    Ive had a fair bit of trouble with this method. Did over 100 fixtures this way cause that's what the customer wanted in his office cause he didn't want to pay for new fixtures. Problems were -

    1) a lot of the LED tubes will only work with newer electric ballasts, we ended up having to upgrade a lot of them.

    2) we're still going back to replace ballasts.

    Bottom line is it might save some money now, but you still have the hassles of a fixture with a ballst

    And as for energy savings, there is some. You'll have to know which bulb you're going to use to figure out just how much you will save. But you still have the loss from the ballast

    Sent from my SM-G950U using Tapatalk

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    I always recommend bypassing ballasts when switching to LED tubes.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

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    Quote Originally Posted by LarryFine View Post
    I always recommend bypassing ballasts when switching to LED tubes.
    Which can make a difference in which tubes you will purchase. Some are designed to operate on the existing ballast, some must have line volts directly applied and there are some "hybrids" that can work either way. I can't tell anyone what the advantages/disadvantages of any of them are, other than I have had a couple clients request not to utilize existing ballasts for a changeout - part of why they are considering change is the fact they seem to change a lot of ballasts already and are afraid they will continue to have to change ballasts after the switch to the LED's. Makes sense to be concerned about that, I don't know if LED's will give same kind of failures on ballast as higher watt lamps they were designed for do.
    I live for today, I'm just a day behind.

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    Quote Originally Posted by nizak View Post
    Is there much energy savings in just changing the tubes in a fluorescent fixture to LED? Unlike the fixtures that are straight line voltage (120-277) LED, the ballast is still functioning in the old fixture.
    There is energy savings. Question is whether financially it is worth investment to change, unless changing when old unit fails. If you have say 10 hour operation per day that energy difference pays for itself much faster than if you only have 10 hours of operation per week and might not be worth the investment at all if you only have 10 hours of operation per month or more, change it when the fluorescent fails, which could be a very long time if you don't normally have much operation time.

    If you get rebates from POCO or other entities for installing such energy efficient lighting that can make it more worthwhile also, but still may not be worth investment for some areas that see little usage. If payback in energy saved will occur in 3-5 years or even less it is well worth it.
    Remember that payback also has to cover cost of installation/conversion.
    I live for today, I'm just a day behind.

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    Quote Originally Posted by nizak View Post
    Is there much energy savings in just changing the tubes in a fluorescent fixture to LED? Unlike the fixtures that are straight line voltage (120-277) LED, the ballast is still functioning in the old fixture.
    Percentage-wise, yes, LED bulbs use about 30 to 40% of their fluorescent counterparts for the same output.

    How long this will take to pay back is going to depend on how often those lights are on.

    If the labor cost to install the bulbs is high, there is more incentive to bypass the ballast so you don't have to go back up there and change it or bypass it later when it fails before the bulbs do.

    in a newer office building with 8-foot ceilings, the lights are on maybe 10 hours a day, the existing ballast are likely original to the fixtures and fairly new, and you can work after office hours, drop-in replacements are a good choice.

    In a 24-hour supermarket, where the lights are much higher, and replacing single ballasts here and there would be a monumental pain in the butt after the fact, I would go ahead and rewire all of the existing lights to bypass the ballast.

    Recently I calculated the time for 100% ROI for replacing 400W MH parking light lamps with a 120W ballast bypass corn cob style LED. It was right at 2 years.

    A single LED replacement in a electrical room or other seldomly occupied place may never pay for itself over a fluorescent tube.

    In real estate they say location location location.

    Choosing an ideal LED replacement is all about application.
    Electricians do it until it Hertz!

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    This is related to the LED power and the number of LEDs you use, circuit routing and other issues to analyze

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    Quote Originally Posted by nizak View Post
    Is there much energy savings in just changing the tubes in a fluorescent fixture to LED? Unlike the fixtures that are straight line voltage (120-277) LED, the ballast is still functioning in the old fixture.
    No. I wouldn't even bother. If there are any energy savings, its probably going to be because you are getting less light in the space. I've seen some of these retrofits that look terrible.

    One big advantage of LED is the light can be aimed, and the optics in fluorescent fixtures just weren't designed to work with the directional LED sources. So you just don't get the same savings you would have by installing a new LED fixture. And you will still have some unnecessary ballast losses if the ballasts are left in the circuit.

    On the other hand, retrofit kits that eliminate the ballast and replace the reflector/optics might be worthwhile if you really don't want to change the entire fixture.

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