# Lighting: Help me understand the difference between T8 and T12



## LeeBarker (Aug 6, 2010)

Visited a friend's shop this week and he has a new, 4 tube 4' T8 light fixture, hung directly over his workbench (but safely above it).

It is uncanny, this desire to want to be in that light. It is magnetic, in a sense. That's a visceral response; the intellectual one is, boy, I can really see everything very clearly here.

Once the electrician had installed the light and turned it on, the owner said, "Put me on your schedule to come back and do two more."

I'd like some good information on the difference, both functional and investment (installation and operating cost) and anything else that would help those of us who are in the dark make an incremental improvement in that state of affairs.

Kindly,

Lee


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## TravisH (Feb 6, 2013)

A lot of what you describe is the K rating of the bulb. Cost between t8 and t12 is virtually the same unless we get into lighting building the size of stadiums (becomes more about the ballasts used).


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## JustJoe (Oct 26, 2012)

T12 are phased out, no longer being produced, obsolete. 
That should make it a bit easier to pick T8 or T5.

The T means tube, the number is the diameter in 1/8 (T12 is 1.25", T8 is 1" diameter).
The smaller the diameter, the more efficient to an extent.
For the 48", a T12 is 78 lumens (brightness) perwatt, and a T8 is 90 an T5, if you have the $, is 99.
And the color rendering index (CRI - wavelengths covered, bigger makes it look more natural) is better too.
For T12 it was low 60s, for T8/T5 it is mid 80s.

Because of the new regulations phasing out T12 and incandescents I'm sure the internet is full of sites that can explain it better than that if you try googling "difference between fluorescent lights" or "T12 vs T8 vs T5" might get you something better.

My workshop is full of 8' T12s. I hope they don't burn out before I die.


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## tefinn (Sep 23, 2011)

Hey Lee, there's not a lot really to say about them. The T8's use less electricity than T12's and put out brighter light. The T12's are no longer made in the US, so the cost of the T8 fixtures has dropped and is now comparable to what the T12's were. They install exactly the same as T12's. If you have T12 fixtures, you can even convert them to T8 (the pins and length for both types are the same) by changing the ballast and installing new T8 tubes. The ballasts cost the about the same as the old T12's did. I bought mine at HD for about $15 each.

As far as operating cost, they do save money on the electric bill. I grow tropical plants/orchids (my other hobby) under lights and have six, three shelf stands with a two light fixture on each shelf. That's 24 light fixtures with 48 bulbs that run for 12hrs a day. After converting them all from T12 to T8 my electric bill dropped over $40 a month.


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## JustJoe (Oct 26, 2012)

Tom - please explain (maybe in another post or an instructional blog) how to do that ballast changeover. I've got 4 of the 2-tube 8' fixtures and a couple of the smaller ones and only one T12 spare bulb left.

Edit: Thanks.


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## TravisH (Feb 6, 2013)

Wood… Best-Ever Home Shop Ideas 2013 (Displayed until December) has a 4 page article on shop lighting.


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## patron (Apr 2, 2009)

i had a slew of t-12 fixtures i got on sale years ago
put 12 of them up in my spray booth
(so i don't have to bend over and move around 
to see the actual work surface)
got a bunch of t-12 tubes for them
but only a few worked the rest flikered or didn't light at all
returned them and got other boxes
(one turned out to be some guys old ones
he had taken back and got his money back 
as if they were new in the same box)

well it turns out the ballasts were no good in my fixtures
and they don't even sell them on ballast sites either
(cheap stuff works that way)
so now i am looking for enough money to get the t-8 fixtures
as i have 24 brand new t-8 tubes

i will 'watch' this page
for more info on this too

thanks lee for this post


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## BillWhite (Jul 23, 2007)

I have 8 two tube T-8 fixtures in my shop. 9 foot ceilings painted a slight off-white. Very pleased with the lighting though I do use some task lighting for the lathe, drill press, and bench grinder.
Bill


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## JayT (May 6, 2012)

T12's are still being produced, but there had to be a change in the phosphors used (the white powder that glows under electric current, producing the light) and the CRI. The effects of that change are 1) new T12's are not as quite as bright as previously and 2) they jumped dramatically in price.

The biggest difference, as Joe mentions is efficiency. Overall, T8's use electricity about 25% more efficiently than T12's, so you get a lot more light for the same energy or the same amount of light for less energy. Additionally, this efficiency allows lower heat levels in both the bulb and ballast, so T8's last much longer-up to 40,000 hours in some commercial bulbs. The real key to the longer life, though, is degradation. All fluorescent bulbs become less efficient over their life, but the drop off for T8's is much slower. For instance after 10,000 hours a T12 might only be putting out 65-75% of its original light, while a T8 will probably still be in the 85-90% range.

In general, switching from magnetic ballasted T12 fixtures to electronic ballasted T8's will pay for itself in energy savings in around two years. Bulb replacement costs will also be much less, both because of price and longevity. Add the broader choice of light colors and T8 gives the most choices at the moment for good, efficient light.

T5's are even more efficient, but pricing and readily available bulb options doesn't make them feasible for most consumers, yet.

Color temperature is another area that you will want to address. These are measured in degrees Kelvin and basically the higher the number, the closer to color is to natural sunlight. Additionally, the higher the number the greater perceived light output, even though the actual lumen output doesn't change. For a basic rundown.

2900K is soft white-a yellowish light that is easy on the eyes for tasks such as reading, but gives very poor results for determing color.
3500K & 4100K are considered to be cool white. These are the most frequently used color temperatures in office environment. 3500 is a bit more pink and 4100 more blue. Again these temps will not give accurate results for color.
5000K & higher are considerd to be daylight bulbs. 6500K is probably the closest to sunlight that is readily available. Color accuracy is excellent, but the light can be harsh on the eyes and tiring.

In an ideal world, I would have 4100K bulbs over my working areas as the best combination of light output vs eye strain and 6500K in the finishing areas so that colors are seen accurately.

I understand there is a lot of information to try and digest, I deal with it almost daily, but I would really recommend anyone switch to T8 when possible. It pays for itself in very short time.


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## tefinn (Sep 23, 2011)

Joe - It's very easy. All you need to do is cut the wires on the old ballast (after you turn the power off of course) and connect the wires to the new one using the diagram that comes with the ballast. Blk to Blk, Wht to Wht, One Blue to one tube end, the second Blue to one end of the second tube and Red to the opposite end of both tubes. The new ballast's have no Yellow wire. Now each tube is wired independent of the other, so if one goes out or is removed, the other stays lit.


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## bbc557ci (Sep 20, 2012)

Couple of weeks ago I finished putting up the lighting in my new shop/garage. 36' x 26' with 12 foot ceilings. I painted the entire inside a light colored antique white in semigloss, ceiling included. Then hung/screwed nine - 8 foot T-8 fixtures directly to the ceiling. Each of the nine fixtures takes 4 bulbs. Lighting in the shop is really great, seems just like being outside light wise. Plenty of fixtures/lights evenly distributed and the semi paint is great for light reflection so zip/nada for shadows )

Before addressing the lighting I had read here on LJs that T-12s would soon be or are/were getting phased out and or harder to buy. Building the shop got me about broke, so price was more of a consideration than the latest wiz bang in lighting. T-8 was cheaper than the T-5 so that's the way I went. I' m real happy with the results.

Just hope the progressives/socialists in our government don't phase out the T-8s too soon ;o)


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## patron (Apr 2, 2009)

in my 30'x60' old shop
i had 3 rows of lighting every 10'
alternate t-12 tubes and 300 watt incandescent pool table fixtures
each row switched independently
(i had read somewhere that tube lighting alone was not enough)

this was before Al Gore invented the internet
and at that time just regular tubes were available
(at least at the big box stores)

thanks everyone for clearing this up

*JayT*
you mentioned hd as a source for the ballasts to swith over to

do you have a code # or brand to look for there


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## TravisH (Feb 6, 2013)

There are a lot of aspects that effect comparisons. You see the common ones from wood working sites mentioned here. Get into aquariums and you see a lot of other variables. I have some t5HO systems over my reef tanks that easily throw more usable light because of the reflectors, ballasts, and fans to cool the bulbs/ballasts than units from big box stores (would have to run more bulbs on the box stores) but we are in a totally different price ballgame with these units (550 for the fixture and mid 20s for a light bulb).

A lot depends on the shop size and how long you will have the lights on. My small shop we are talking chump change between the different lighting options. I like the highest CRI rated bulbs I can get. Currently running screw in flourescents over my work bench that are a 6500k "full spectrum". Nice white crisp light with accurate color representation.


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## JayT (May 6, 2012)

Actually, that was tefinn that mentioned HD. The company I work for is a competitor to them, so I definitely wouldn't be buying at big orange 

Regardless, there are several manufacturers and all the models will be different. Any good hardware store or home center will have ballasts. All you need to know is how many bulbs and what length/size, the ballasts will be labelled that way. For instance, in Joe's case, he just needs to find a ballast that is for 2 F96 bulbs and he is good to go. The new electronic ballasts are all rated for T8 or T12, and as tefinn mentioned, the ends are identical.

Edit: If you take the bulb information in to a store and they don't know what you are talking about or can't immediately help you find the right ballast, RUN, don't walk, away and go somewhere where the staff in the electrical department actually has some training.

The most common configurations for T8 are either two or four bulb F32 fixtures, which use 4' long bulbs and two F96 bulbs, which are 8' long.


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## TheDane (May 15, 2008)

Lee-When I built my new shop in 2012, I had the electrician install T8 fixtures … 4 4-tube fixtures in the shop itself and 3 4-tube fixtures in the adjacent garage. We used the 5000K Full Spectrum bulbs. With bright white walls and ceilings they do a fine job.


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## TravisH (Feb 6, 2013)

Amazing what some white paint will do. I painted some of the panels this last time and it made a difference for sure.

I have replaced several ballasts on fixtures with Fulham Work Horse Ballasts. Never had any complaints with them and they have about every possible wiring combination on the website if one wants to make sure.


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## KMTSilvitech (Feb 10, 2011)

I am just in the finishing stages of my new to me shops interior. Having completely stripped the wiring throughout. There were wires pigtailed together outside of boxes everywhere. It had 8 4×4 t12 lights in it, no ceiling, just attached to the trusses. I put unfinished osb board on the ceiling ( I bought it at an auction, 30 sheets right out of the osb plant for $60.00 ) I am installing 12 2 light x 4ft T8 lamps with diffusers directly mounted on the ceiling with 5000k bulbs. The lighting difference is astounding from the old ones. Now maybe the bulbs of the T12's were quite aged, not sure. The biggest difference for me is the electronic ballasts, I can walk in and hit the switch and not wait for 15 minutes to see where I'm going. Have 4 more to install today.


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## patron (Apr 2, 2009)

sorry *JayT*

HD is an hour and a half away from me anyway
so lowes it is for me 
good to know all this stuff

(i did look on-line at ballasts
totally overwhelming the stuff they had)

with your input i can look again if needed
this time for specific ballasts
based on the tube requirements


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## BArnold (May 20, 2013)

Operationally, there's has been a tremendous difference in my experience.

For many years, I bought the usual "shop" fixtures because they were inexpensive. In reality, they were simply "cheap". They worked - for a while - but I had to replace the entire fixture every year or two. All of them used T12 bulbs.

Fast-forward to 2006 when I started building my new shop. I wanted something more reliable so, after some research, I settled on some T8 fixtures that were more of a commercial design and cost several times what the cheaper ones had cost. BUT, in seven (7) years of operation, I have yet to replace a single bulb! I have never had any flickering. When I flip the light switch on, ALL fixtures come on at the same time - none of the "maybe I will or maybe I won't" garbage of the T12 shop lights.


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## teejk (Jan 19, 2011)

I switched to T8's years ago mostly because of the ability to handle cold weather (0F start because of the ballast). I think the bulbs last much longer. And I have to question whether it makes sense to swap ballasts (the ballasts I have looked at cost a lot more than the entire fixture). Menards sells a nice fixture using 4 4'foot tubes and I prefer hauling them over 8' tubes.


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## JayT (May 6, 2012)

teejk, I usually recommend either replacing the ballast or going with a commercial grade fixture. The replacement ballasts you can buy are generally a lot better quality than those that come in the promotional and entry priced fixtures. Just like a lot of things, those inexpensive fixtures had to have some cost reductions to manufacture that cheaply and the ballast is the one area they can cut that most affects performance.

BArnold shows the difference in his post above. That experience isn't T12 vs T8 as much as the quality of the ballasts in the fixtures.

*patron*, I glanced at Lowe's website and they carry Phillips/Advance ballasts. They, along with GE, are probably the two most common manufacturers of good quality ballasts. If your local store has the commercial ballasts in the size you need, I would recommend going that way instead of the residential line, because of the reasons above. The extra upfront cost will be worth it.


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## JayT (May 6, 2012)

Back to the OP. Lee, what is the ceiling height you are working with? If the lights are or can be mounted at least 12' off the floor, you might want to look at high bay pod fixtures similar to these. While not inexpensive, this type of fixture gives very even spread and great quality of light for an entire area. These high bay fixtures in various configurations are extremely popular in all kinds of commercial shop, warehouse and retail environments. There are quite a few manufacturers and an electrical contractor should have easy access to a quality brand.


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## longgone (May 5, 2009)

I have T8 fixtures in my shop since I built it early 2008. The lighting is excellent but the most noticeable improvement came when I changed all the T8 bulbs to the daylight T8 bulbs.


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## RogerInColorado (Jan 18, 2013)

I had a cheapie shop T12 light that I had been given crap out. I replaced it with a 4 bulb T8. I believe that in addition to being less expensive to operate and providing much more and better light, that it made me smarter, taller and better looking. It has not, however caused my hair to grow back. I can't wait for the rest of my T12s to fail.


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## tefinn (Sep 23, 2011)

I'm with JayT, the replacement ballasts are much better than the ones that come in the cheaper fixtures. In the case of my plant stands, the special fixtures needed would have run nearly $200 each vs. $15 each for the ballasts and the tubes. I replaced all the ballasts and tubes about six years ago and have not had to replace anything since.


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## shawnmasterson (Jan 24, 2013)

if you look at your ballast some of them can run t12 or t8.


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