flourescent replacement - LED's

dadgardensMay 24, 2011

I am hoping that someone can give me advice on replacing some fluorescent fixtures with LED's.

The fixtures use "Phillips F40T12DX bulbs at 40 watts"; the tubes and ballasts are at the end of their life cycle; tubes have been replaced twice/thrice, the ballasts - not at all. Yep, we're talking about 25+ year old fixtures.

I am looking for an LED replacement for the 2-tube/ballast system that I have now!

I am trying to match color rendering, color temperature, and Lumen output, with LED tubes.

If I can do that, without spending twice as much as ballast/tube replacement will cost - I will!

I don't like the buzz! From the ballasts - never did, still don't!


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The buzzing you hear is coming from the magnetic ballast which is typically used with older T12 tubes.

There are direct LED replacements such as

Search for T12 LED replaccements.

Alternatively, you could replace the T12 fixture with a T8 equivalent. The T8 fluorescent tubes are more efficient.

If the fixture is a fluorescent troffer, you may want to consider waiting for the latest CREE CR24 troffer.


Here is a link that might be useful: Cree CR24 description

    Bookmark   May 24, 2011 at 12:22PM
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Not sure the cr24 is available yet, but it looks great. I can't seem to get final pricing yet though my Cree rep.

    Bookmark   June 5, 2011 at 12:58PM
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It is available from the light bulb emporium

    Bookmark   June 5, 2011 at 2:00PM
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The Cree cr24 is? That's great.

    Bookmark   June 5, 2011 at 5:20PM
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Yes, I asked and was given a quote of $318 for a 2x4 troffer.

Apparently, the 2x4 troffers are shipping in June. The rest of the line will follow in the coming months.

    Bookmark   June 6, 2011 at 12:02PM
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Not a bad price for what you get. I like this for garage lighting and in office buildings. Thanks David.

    Bookmark   June 6, 2011 at 10:42PM
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I would like more information on the 2x4 'troffers' (two tube fixtures)(?) you mentioned. But $318.00 per fixture seems a bit high; since I have fixtures in place (re-wiring is not a problem)

Replacing both ballasts and four tubes won't cost me as much as 1 fixture would (even with electricity at $0.6146/ Kwh). I have not taken the time to compute the electrical cost 4 - 6 hours per day (5 days/week).

The price seems a bit too high.

    Bookmark   June 7, 2011 at 2:18AM
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The initial cost may be higher, but the savings over the long haul make it a no brainer. If you look at it like that, the troffer makes total sense.

    Bookmark   June 7, 2011 at 2:38AM
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The pricing of the CR24 is in the ballpark of what an equivalent fluorescent troffer (for commercial use) would cost.

Having said that,
If you don't need the entire troffer, it would be simpler to upgrade to electronic ballasts + T8 tubes. They last far longer than the CFLs.

I'm not 100% sold on the LED T12/ T8 replacements just yet as there is a wide range of claims, quality (and pricing) of the LED replacements. In the meantime, I still have spare T8 tubes.

I've included the link to the description of the CR24 again.

Here is a link that might be useful: CR24 description

    Bookmark   June 7, 2011 at 1:16PM
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Net summary - LED T8 replacement lamps not quite ready. NB - this study did not cover the CR24.

Here is a link that might be useful: Lab eval of LED T8 replacement lamps

    Bookmark   June 7, 2011 at 6:35PM
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Retrofitting F32T8 lamps with electronic ballasts will give you efficiency equivalent to the Cree, over 100 lumens per watt, at a fraction of the price.

The long-life LED troffers make a lot of sense in offices and other institutional settings, where lamp replacement is carried out by well paid labor. In other situations, fluorescent is still the way to go.

If lamp life is a factor and you expect to switch the lights on and off frequently, spring for a programmed-start ballast. This may cost more initially, but a T8 lamp driven by a programmed start ballast will typically last for 50,000 starts. An instant start electronic ballast will give you 10,000 to 20,000 starts.

If you want a totally silent ballast, get GE Ultramax. I have them in several fixtures, and they're completely inaudible in every case.

    Bookmark   June 7, 2011 at 8:15PM
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It looks like I should consider re-fitting my fixtures, with new ballasts and tubes with F32T8 lamps; at this time.

I am assuming that the change only involves ballasts and tubes. Are the bases of the tubes compatible - can I use T8 tubes in 25 year old T12 fixtures with the right ballast change. Or, will need to change the fixture, or its tube connections?

I am still trying to sort out "instant start" vs "programmed start" ballasts - technology always changes!
I let myself get complacent, my mistake (mumble-mumble)!

Thank you, (and my apologies for grumbling about the cost)

    Bookmark   June 8, 2011 at 1:57AM
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can I use T8 tubes in 25 year old T12 fixtures with the right ballast change

Sure can! The "tombstone" end connectors are the same. You may have to wire them differently, however. See the wiring diagram on the ballast.

I've done this with several old fixtures - kept the very solid old steel housings, replacing the ballasts with modern electronic ones and the lamps with T8s. In some cases, not all, I also repainted the housings.

Programmed start ballasts are an evolution from programmed rapid start ballasts. The latter provide slightly less lamp life but IIRC are about the same price these days.

PS ballasts are the way to go if you switch your lights on and off several times a day. If you turn them on in the morning and off 8 hours later, instant start will be fine and will cost less. The difference is that PS ballasts are "smarter" and thus gentler on the lamp when starting it.

    Bookmark   June 8, 2011 at 3:18AM
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Following a schematic is not a problem; the same 'tombstones' is good news for me!

Yes, I am working with solid steel housings (surface mounts that look good).

The PS ballasts sound good; how long do they take to get to full brightness (ballpark estimate)? I have too many CFL fixtures that take several minutes to 'warm up' to full brightness.

Can you give me some suggestions for replacing my F40T12DX twin tube fixtures; the ballasts and tubes?

Current usage is intermittent/sporadic (due to the economy), normal usage would be 'on' for 6=8 hours/day

What does "IIRC" mean/refer to?

Thanks for the help.


    Bookmark   June 9, 2011 at 1:58AM
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how long do they take to get to full brightness

The few that I've seen so far have come up to full brightness within a second of being switched on.

suggestions for replacing my F40T12DX twin tube fixtures

I have yet to install a programmed start ballast myself. (Haven't had any recent failures or conversions.) So I have no specific brand recommendation there, sorry. Someone else might.

For instant start ballasts, I generally use Advance Centium (now owned by Philips) for cellars, workshops, and garages. They hum slightly, but are fairly inexpensive.

In living areas, I prefer GE Ultramax ballasts. They cost a bit more, but are completely silent.

Assuming you want normal light output, choose a ballast with a ballast factor in the high 80s. Lower ballast factors reduce energy use, but the light is dimmer, and has a sort of greyish quality.

For the T8 lamps, it's usually not worth going to the big box stores. You'll find a better selection at a local lighting vendor, or an electrical shop that serves the pros. In my experience the price is similar and sometimes even cheaper than the big box stores'.

The lamp's color temperature is really a personal preference thing. A 3000K lamp is fairly warm, close to incandescent color. At 3500K, the light is whiter. The standard cool white color is 4100K. Above that you get into daylight simulations.

You'll find that all of these light colors are much more agreeable with a high CRI (color rendering index). The old cool white and warm white halophosphate-phosphor lamps had CRI in the 50-75 range. Modern T8 tri-phosphor lamps normally have CRIs in the 80s.

Somewhere in the lamp's number you will usually find a 3-digit code. This is typically 730, 735, 741, 750, 765, 830, 835, 841, 850, or 865. The first digit represents the CRI (76-78 range or 82-86 range), and the last two are the color temperature (3000, 3500, 4100, 5000, of 6500K). I mostly use 830 and 835 lamps.

What does "IIRC" mean/refer to?

"If I recall correctly."

Good luck, let us know how it comes out.

    Bookmark   June 9, 2011 at 8:15PM
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Thank you!

Now I just need to find a nearby local electrical/lighting vendor, 2HD's and Lo's nearby.

I did understand color temp and CRI - but did not know about the three digit code on the tubes.

CRI's in the high 80's for 'tri-phosphor' bulbs is better news. Yes, I knew I had 'older' lighting technology in my home office; I did not know how much better some of the newer tech could be.

The ballast factor is new to me, but I did a few quick searches, and found out that it deals with the ballast's effect on Lumen output, or tube longevity. GSTK

And, I actually thought that IIRC referred to some obscure/arcane electrical protocol.

I'll save money by buying two electronic (GE Ultramax (or similar), ballasts and four T8 tubes. The LED's can wait a bit.

Thanks again,

    Bookmark   June 10, 2011 at 1:46AM
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I replaced one of the magnetic ballasts, took a while to figure out the wiring.

Old style/school magnetic ballasts have b/w supply lines; two red lines, two blue lines, and two yellow lines. New school, electronic ballasts; lack the yellow lines; and have 2 blues and 1 red (2 reds and 1 blue?) it was hot, upstairs! I re-wired the fixture to fit; and got irritated by a defective tube - oops!(Added by the heat issue)! I thought that I made a mistake, bad tube - time/sweat wasted!

I went to HD! It was closer than the next lighting outlet by about 20 miles!

Quiet light, is different!

I will replace the second ballast - now that I know what is involved!

Question: Are magnetic ballasts banned/illegal in NY?

The conversion took some trial/error; but got done!

HD's tube recommendation was wrong! - 3,000 k Phillip's is not white light! Yellowish-orange (incandescent - at best)!

I will replace the second ballast; and, all 4 tubes with better tubes.

You wanted some feedback; the conversion involves some trial/error. Complicated by a bad tube!

Silence is unusual, and different!

The re-wire was a pain! It got done! HD falls short! As usual!

Schematics were helpful(?) - trial and error worked best!

Heck, I got it working!


    Bookmark   June 21, 2011 at 2:17AM
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One F32T8DX bulb from Phillips 'seems' to deliver as much light as two F40T12 CW PLUS tubes, is this possible/logical/rational?

Or, Am I mis-judging the output of new tubes versus 4 year old; older tech tubes?

BTW, you were right about big box stores - defective bulb/used bulb (I got one of each) - I should have driven a few miles more than I did!

One 32W tube seems/appears to be brighter than two 40 watt (DX) tubes on magnetic ballasts! Is this possible!

I used to be play around with photography! Natural light was important!

I used to get a true white - DX has a blue light! Is there a white tube , that is not 'warm'; or blue?


    Bookmark   June 25, 2011 at 2:00AM
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Yes, this is possible since the T8 tube + electronic ballast is more efficient than the T12 + magnetic ballast.

    Bookmark   June 25, 2011 at 12:43PM
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The power input lines are the same: black to black, white to white; the ballast's outputs are different! Blue to blue; second blue to red; and, red to yellow (on the tombstones). (For other DIY'ers!)

The conversion went - okay, HD was the problem (?) Maybe(?) One tube was much brighter than the second tube! Hmmm! Used tube, repackaged or a defective tube.

Anyway, 3 32W tubes are better than 4 40W tubes!

Thank You!

    Bookmark   July 3, 2011 at 1:50AM
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Hey Dadgardens,

I was going about doing this in my home as a DIYer, and I realize this is now a few months past your post, but did you SHUNT your tombstone connections? Or did you buy new tombstones for that were already shunted for the instant-start ballast?

For the sake of others coming to this post via search (like I did): The wiring for the ballasts was different b/c you had a Rapid-Start ballast (just like mine) and replaced it with an electronic Instant Start ballast which is wired differently (old one heated up the ends of bulbs on starts & new one doesn't, there's more to it in the link). That was obvious with the fewer wires in the ballast diagrams. What wasn't obvious was shunting.

Anyway, if you didn't shunt, that may be what happened with your "bad" bulb from HD. Supposedly, you'll get intermittent bulb failure if the shunting was skipped. Shunting involves cross-wiring the white wires at one end of the tombstone and the blue/red at the other end (in short, you can snip the existing wires and put wire nuts on them).

Alternatively, if you buy a Programmed Start Ballast, for those frequently on/off locations per the helpful instructions by DavidR earlier in the post, you do NOT need to shunt and the wiring would've looked the same with the blues/reds/yellows as the old magnetic ballast.

I've seen several instructions online: "to upgrade from T12 to T8, you just need to replace the ballast per wiring diagram & put in new bulbs!" Which is not entirely correct. In some cases it might be true, but certainly not all.

I came to this forum asking for confirmation on the wiring for shunting, so just thought I'd share.

    Bookmark   October 18, 2011 at 5:06AM
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Forgot to include the link.

And also forgot to ask: perhaps you bypassed shunting by connecting each single wire from the ballast to both wires from the older tombstone.

I'm only asking to offer friendly advice, not to criticize your work, and to help any others that come across your post.

Here is a link that might be useful: GE Link

    Bookmark   October 18, 2011 at 5:52AM
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Wow, I wish I had found this thread a few months ago. I have pretty much decided that retrofitting good-quality, 4-foot, T12 luminaires with new, programed-start T8 ballasts and tubes is the way to go. That is especially true if you can find a good price on ballasts. (I am still grinding my teeth on what to do with about 15, 8-foot fixtures that I own.)

IMHO, it borders on criminal to market the "residential grade" ballasts to people that will install them in residences. The kind of frequent switching that they see will trash the tubes in a relative jiffy while a ballast rated for occupancy sensor use is most appropriate. Then there is the power factor thing. An individual will not pay for the extra volt-amps used by a cheap ballast in a residential situation, but everyone will.

The ballasts can be tough to find on the shelf at mass market stores. If you have enough conversions to do, you can find good enough deals on case quantities so that you will spend less and have some spared left over for less than buying them off the shelf. Good tubes can be hard to find in consumer-oriented stores as well.

    Bookmark   May 14, 2012 at 11:36AM
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