At BulbsDepot.com we get this question all of the time (and we never mind answering it!) but we thought it might be good to put the answer in our blog so our customers can refer to it from time to time.  In addition to knowing the difference between them people also want to know which one is better, more efficient, etc.  Let’s try to shed some light on the subject (pardon the obvious pun!).

The main difference is in size…the T8 is one inch in diameter and everything else is divisible by that number:  T5 = 5/8 inch, T6 = 6/8 inch, T8 = 1 inch, T10 = 1.25 inches (10/8), T12 = 1.5 inches in diameter (12/8).  While the size is the main difference there are other differences that are worth mentioning.    

We also get the question – what is the “T” for in all the lighting jargon?  The “T” is for “tubular”.  It’s that simple.

The questions of which one is better is a tricky one – there are different sizes so the lighting can be applied for different application, so there really is not a better choice than another without understanding the lighting application for which it is intended to be used.  The lighting efficiency goes up with the thinner bulbs, providing more lumens per watt.  That difference is what makes each configuration unique when comparing the fixture, lamps and ballasts.  They all must align to provide the most efficient environment for the lighting application. 

The higher output lamps (HO – High Output and VHO – Very High Output) require higher wattages and special ballasts to control the flow and help to start the lamps.  While these lamps do produce more lumens, they are not as efficient with electricity and tend to run hotter because of the increased wattage.  

We also get asked which type of lighting is the most efficient lighting.  That question can be mathematically answered but again, you have to consider the lighting application.

Generally speaking and using T12’s as the baseline, a T8 is 40% more efficient than a T12.  A T5 is more than 50% efficient than a T12. 

The environment also plays a big factor in selecting the right fixture, lamp and ballast for your lighting application.  The most common 32 watt, T8 lamp with an electronic ballast is the standard in the lighting industry for proven applications.  This configuration has withstood the test of time in very frigid environments, factory settings and even parking garages. 

While the T5 is superior in efficiency it needs to be used in the right lighting applications.   A T5 does not fit well into the applications listed above.

Talk to us – we will help you to determine the best technology for your lighting application and will help you to consider the cost savings associated with upgrading the lighting applications the next time a replacement is necessary.