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T12 vs T8 vs T5: "T-12"...As Outdated As Your Granparents Bingo Game?


T12 vs T8 vs T5 ...  Are We Playing Bingo?t12 vs t8 vs t5 is this our grandparents bingo

But of Course, Bingo doesn't have the T, so we must be talking about lighting.

While the T has no place on bingo night with our grandparents, the old T12 lighting will have no part in the discussion of energy efficiency or even fluorescent lighting in general. 

The old T12 technology is likely what it lighting the bingo hall right now!  (.....someone needs to talk to them about efficiency!) 

But just like the old bingo halls, T-12's are disappearing.  After 2012, they will no longer be manufactured.  In fact, most of the utility rebate programs are eliminating the incentives for T-12 replacement very soon.  So....what do you do now?

Understanding The "T"?

Quite simply, "T" is the diameter of the tube in the lamp.  A T12 bulb will have a diameter of 12/8". (1 1/2" for those of you who prefer the simplest form)  That would then make the T8 smaller, and the T5 smaller yet.  Typically the more narrow the lamp, the more efficient it will be.

So We have:

  • T12 = old and inefficient
  • T8 = higher efficiency
  • T5 = highest

Is There A Cost Difference Between T5 vs. T8?

Here is the cost breakdown between T5 and T8 assuming we are talking about the standard 4 foot lamp:

  • T8 = $3.00 - $5.00
  • T5 = $5.50 - $12.00

All lamps have a general life expectancy of around 36,000 hrs. at 12 hrs. per day burn time.

T5 costs significantly more than T8 but does not outperform it by the same margin. In fact, in many low level interior applications, the performance differences are negligible.

In Comparison to the T12:

This isn't really relevant unless you are stocking up on the old T-12 bulbs, you may want to take the cost comparison into consideration. As the manufacturing of the bulbs cease, the cost of T12 bulbs will continue to increase due to declining supply.

  • T8 = roughly 20% more expensive than T12
  • T5 = 2-3 times the cost of T8

Comparing "Brightness"  T8 vs. T5

The Department of Energy calls it "Brightness" (as does my 6 year old) but it is actually lumen output.  This, among other factors is an important part of determining different levels of efficiency. 

Two characteristics of light that we like to look at are Quality and Quantity.  They are measured as follows:

  • Quality:  CRI = Color Rendering Index
  • Quantity:  LPW = Lumen's per Watt

So, what is the best light to use if the ceiling is lower than 12'?

Here's an average scenario:

CRI Levels:

T12=62 CRI

T8=85 CRI

T5=85 CRI

LPW Levels:

T12=78 LPW

T8=90 LPW

T5=99 LPW

 In this scenario, the T5 would be the exact same quality and the increase in quantity would be insignificant.  It would not be worth the money to invest in the T5 lighting when you consider having to replace the fixture, lamp and ballast.

Where SHOULD We Use The T5 Then?

As you can see in the above scenario, it is not always recommended that you switch from T8 to T5, but if you have the old T12 and must replace them with something, it would be best to go with the T5.  

Learn More About Energy Efficient Solutions For Your Business

Knowing what energy efficient technology makes the most sense for your facility can be an overwhelming task to figure out.  You may think, "but it's just not worth it!". 

You may be right, but how will you ever know without doing some research and planning?

We created a FREE ebook to help you understand the benefits of an energy efficient solution for your business.  Download by clicking on the book cover below, it's FREE:


Other Articles Related To Fluorescent Lighting You Might Like:

T5 Lighting: 5 Reasons Why T5 Lighting Puts T12 Lighting In The Dark

T5 vs. T8: How Do You Know If You Really Need T5 Lighting?

T8 vs. T5: How To Determine Which Light Is The Right Light

T8 Lighting: Energy Efficient Applications And Uses For T8 Fixtures

Energy Efficient Solutions: How To Transform Existing T12 To T8




I'm building a new wood working shop. The size is 26'x40'. the cieling is 9'6" high. How many fixtures would you reccommend and at what spacing. What type of bulb  
how many K?  
Thank you. Ben Snapp
Posted @ Friday, December 28, 2012 7:34 PM by Ben Snapp
You need a total of 8 T8 8' 4 bulb fixtures. 2 rows of 4. Along the 40' way start the first row 4' from the end of the building and you will end up 4' from the other end of the building with a space of 8' between each fixture. From the wall go 8' to the first row 10' from that row to the next row and you will end up 8' from the other wall. That should light you adequately. Dean
Posted @ Monday, March 25, 2013 4:11 PM by Martin's Electric
Dean your math is a little off...You suggest a row of four 8' fixtures w/ 8' between fixtures and 4' on each end that equals 64' not 40'. Ben I have a 50x36 pole barn (1800sq ft) vs your 40X24 (1040sq ft) I have seven 8' T8 and its adequent lighting. I believe you'd be alright with six 8' T8's
Posted @ Sunday, May 19, 2013 6:02 AM by Andy
The only facts in this article about T12 seem to be:  
+ They are less expensive to buy T8 or T5 
+ Their lifespan equals that of T8 or T12 
How are they actually different? How are they less efficient? Wikipedia says T8 technology is from the 1930s, just like T12.  
So why are T12s bad?
Posted @ Friday, June 07, 2013 1:40 PM by Brian
Andy must have good eyes for only 7 eight footers. I have a 48x32 and I have 12 8 footers and 6 4 footers along where the garage doors open so I can turn them off when they are opne.
Posted @ Sunday, June 16, 2013 10:37 AM by steve
Updating my garage lighting. We need to replace the ballaster, I think? Maybe John can point us, really you in the right direction, thanks!
Posted @ Thursday, December 26, 2013 2:18 PM by Tony
apparently nobody knows that there are t5 HO (high output 240 VAC) I have a 50' x 50' shop which I have wired using t5 HO's...the lighting is at lest twice that of t8's and by far more efficient...
Posted @ Saturday, April 26, 2014 12:18 AM by CHD
>So why are T12s bad?< 
Yes, I don't get that either, unless they are talking about using way behind the times ballasts. I just get my fixtures at Menards. If the ballast cares if it T8, T12, HO, or VHO, it's old technology, and it will probably flicker if you use them in a cold garage too. They still sell old and new technology electronic ballasts. I just checked them with with a kill-a-watt. With one bulb removed from the fixture, the whole shebang uses 26 watts, and with both in it uses 50 watts even. CRI has nothing to do with diameter, it is a function of the coating inside. The bulbs I get are the Phillips, 6500 Kelvin, 2500 Lumens, 90 CRI from Home Depot. I used to get a pair for about $6.00, but I paid $4.32 for my last pair. There is far more available for T12 and they are cheaper as well. It's just a coated tube. So why pay MORE for a T5 or T8, and get less of everything?
Posted @ Tuesday, July 01, 2014 2:35 PM by IT_Architect
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