Buying Guide

Types of Tube Lights

Types of Tube Light Bulbs
A diagram shows the size difference between T5, T8 and T12 tube lights.

While there are multiple types of LED and fluorescent tube lights, the three most common are T12, T8 and T5. The terminology comes from “T” for “tubular” and the diameter of the bulb in eighths of an inch, so “T8” represents a tube of 8/8ths of an inch, or 1 inch.


Tube lights can also be compared by such factors as the power in watts and the amount of light given off, measured in lumen output. The color-rendering index, or CRI, represents the quality of light output, with 100 being equivalent to natural sunlight. 


T12 lights have a regular width compared to the other lights. 

  • Diameter is 1.5 inches 
  • Length is 48 inches 
  • Energy to emit 2,500 lumens is 40 watts 
  • Durability is 10,000 hours 
  • CRI is 62 


T8 lights have a thin width 

  • Diameter is 1 inch 
  • Length is 48 inches 
  • Energy to emit 2,500 lumens is 36 watts 
  • Durability is 10,000 hours 
  • CRI is 85 


T5 lights have an ultrathin width 

  • Diameter is 0.62 inches 
  • Length is 45.2 inches 
  • Energy to emit 2,500 lumens is 28 watts 
  • Durability is 15,000 hours 
  • CRI is 85 
Fluorescent vs. LED Tube Lights
At least, fluorescent tube lights hang in a workshop. At right. LED tube lights hang in the same work shop.

Fluorescent tube lights are low-pressure mercury-vapor gas discharge lamps that use fluorescence to produce visible light. Fluorescent tubes require an electronic ballast to regulate the flow of electricity.


LED tube lights, which use light-emitting diodes to provide illumination, are increasingly used to replace fluorescent lights. Compared to fluorescents, LED lighting lasts longer, is more energy efficient and uses no mercury. Instead of a ballast, they regulate the electrical flow with electronic components that make up the LED driver. 

Switching from Fluorescent to LED Tube Lights
A person stands on a step ladder to switch fluorescent tube lights with LED lights.

LED tube lights not only offer energy efficiency, but bulbs and ballasts for T12 fittings are becoming increasingly rare and T8 bulbs and electronic ballasts may become similarly scarce in the near future. There may be limited options to replace fluorescent bulbs with LED bulbs.


Different types of LED tube lights have different requirements for replacing fluorescent tube lights. 

  • Direct fit or “plug-and-play” LED tube lights can be directly swapped out for fluorescent tube lights with no additional adjustments. They are easy to install but the approach requires continued ballast maintenance. 
  • Ballast-bypass LED tube lights must be retrofit by the removal of the original fluorescent ballast. This option uses less energy but requires rewiring the fixture. 
  • “LED lamp and driver” tube lights must be retrofit by replacing the ballast with an LED driver. This option sees better energy savings and reduced maintenance but higher initial materials and labor costs. 

Just as fluorescent lamps replaced incandescent and cfl bulbs in many lighting applications, LED tube lights are frequently replacing fluorescents. This can require short-term costs but show the benefits of less energy consumption over time. Your power bills may see a brighter future.