Upgrading Fluorescent Shop Lighting

      Shop owners discuss the pros, cons, and practicalities of swapping out T12 fluorescent light units for T8 fixtures and lamps. October 26, 2013

Question (WOODWEB Member)


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I'm planning to convert my T12 florescent fixtures to T8 fixtures. I don't know if I should go with the conversion kits or all new fixtures. Has anyone done this? Are there any pro or cons either way? Did the conversion make any noticeable difference in you electric bill?

Forum Responses
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From Contributor B

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I made the switch last year with new fixtures. After the fact I looked at each new fixture and realized there was as much wattage being drawn by the new T8ís as was from the old T12ís. Just add the wattage of four T8 4' tubes vs. two T12ís at 8'. It was basically the same if not a bit higher on the T8ís.

What you do get though is additional light for the same amount of wattage. What you also get is the eventual lower cost of T8ís as T12ís are phased out and the tubes become more expensive. I also paid more for the fixtures with the top reflector shields. That seems to help reflect more light downward.



From contributor D:
If you have four footers you can just change out the ballast and put in the T8 bulbs. Go to the electrical wholesale house and get to know the person in charge on the counter. He can guide you on what parts to get. In South GA we can get a ballast for about $17, and bulbs for about $2 each. If changing the fixture look into the T8 fixtures that have six bulbs in them. They put out a lot of light.

Depending on how many fixtures you have you want to investigate T5. Again theyíre brighter than T8 as T8 is to T12. Itís more expensive but there are retro kits by Lithonia to go into four footers and theyíre easy to install. I helped a Library swap out about 330 T12 fixtures to T5. We followed up on electrical usage and once we were done we'd reduced consumption by 20%. This is for a 25,000 square foot building with 350 or so fixtures (I didn't work on all of them). That's an impressive figure to me. Retro-fit kits were about $175 if I recall correctly, bought in batches of 100 or so. Either way it's a good fix. You'll be glad you did it. Use your head, if you don't know how to wire then hire an electrician.


From Contributor M

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I recommend you go to T5 if you can.


From contributor F:
So are the 8' bulbs altogether being replaced? Or is there a new version that allows you to keep the old fixtures? I'm not looking forward to swapping out my fixtures since I only put them in about eight years ago.


From contributor D:
T12 is being phased out. Have you ever held a T8 or T5 bulb? Imagine it being eight feet long. There may be 8' T8 or T5 but I haven't seen them and I wouldnít want to change them. I can't imagine them not breaking. For starters, go to Home Depot and look at their fixtures. They have 8 foot fixtures which are essentially two four-footers put together. Next go to the electrical wholesale house and get to know the man on the counter who can help you.

If these are simple shop lights hanging from ceiling you're in pretty good shape. If they are inset into a suspended ceiling it's a different deal but not bad, just a retro kit of some kind, which must come from a wholesale company probably. If it were me I'd buy four footers and hang. You'll get as much light out of a four foot T5 as you did an 8' T12, more actually.

Don't get the least expensive bulbs you can get. Be aware there are different color bulbs so look for a 3800k color, also called 825 I think. Thatís a good question for your wholesale man. Wrong color light is annoying. You ought to change your bulbs out after about two years probably, or at 50% of their life expectancy in hours as they dim considerably after that.

Just get on with it - you'll be glad you did. I echo the comment above about going to T5 if you have to change fixture. The main advantage of T8 besides lower upfront cost is you can retro into existing four foot T12 fixture and still use the existing tombstones to insert bulbs. If you have eight footers this doesnít apply. T5 uses different tombstones so not worth redoing all that, just get a different fixture.



From contributor F:
Mine are all eight foot fixtures hardwired, fixed to the ceiling, and only about eight years old. So now I'd be looking at throwing those away and buying roughly 14 new fixtures. Four footers - so roughly 28 new fixtures, plus a day or so with a helper to replace them all in a building I don't own. I think I'm going to have to stock up on T12 bulbs.

From the original questioner

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I'm leaning toward the conversion kits that turn the 8' two lamp T12 lights into 8' four lamp T8 fixtures. It seems like the least expensive and fastest solution. The kits change the ballast and add bulb holders to make a two light into a four light fixture. Maybe I'll try a run and see how it goes.


From contributor J:
I'm in California, and a PG&E rep came by and offered a subsidized lamp replacement program. It was less than $2k to retrofit all lighting in a 6,000 foot building. Check with your utility company.


From contributor L:
Check with your utility for help on the cost of replacing the T12's. Several years ago we started replacing magnetic ballasts with electronic. When we heard that they were going to ban T12's we started replacing them with T8 ballasts and lamps. Ours are all 8' fixtures and we had been using watt saver T12 lamps so only one watt gain in T8's but they are brighter. I figured out we are spending about $350 a month in electricity for lighting out of a total electric bill of about $1,400.

I've talked to our electric wholesale supply house and they will calculate the lighting levels provided by the various options and help me with the paperwork for the utility rebates. Not all areas of the shop need the same level of lighting. Most of the shop currently has two tube 8' T12's on 10' centers end to end. I'd like to keep the 10' CC distance and not have to redo everything. I found out that the 8' T8 lamps cost a lot more per foot than the 4' ones. To keep long term lamp replacement cost down I'll either end up converting the 8' fixtures to 4' or have to pay a lot more for an electrician to hang all new.



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