Fluorescent lighting has multiple types of bulbs. I am only going to talk about two types, The double pronged T8 and T12. Since these are the most common among us do it yourselfers I will explain the differences.
The first difference you will notice is the physical difference in diameter. The T12 lamps are 1-1/2″ in diameter the T8 lamps are 1″ in diameter. The designation of T8 or T12 describes the physical diameter of the lamp in 8ths of an inch. For example T8 = 8/8ths of an inch T12= 12/8ths of an inch.
T8s use 50% – 80% less energy than the T12s and provide the same amount of light.
Another difference is the types of ballasts used on the bulbs. T8 use an electronic or solid state ballast and T12 lamps use the old magnetic ballast.
If you want to use T8 bulbs and have the old style ballast, the old magnetic ballast will need to be swapped out for the new electronic style ballast.
If saving money on utility bills isn’t enough, there are many more benefits to converting. Using the electronic ballast and T8 bulbs will reduce the buzzing noise generated compared to the old style T12 and magnetic ballasts. Upgrading the bulbs to T8 Daylight (full spectrum) bulbs makes the space more inviting and isn’t as harsh as some other lighting choices and makes taking video or pictures look more professionally done.
With the price being $80 for a box of 30 (32w Sylvania daylight bulbs), I am slowly but surely getting rid of the T12s in my shop, and plan to have it completely converted by 2016 (I am waiting for the rest of my T12s to burn out).