Go for CFL when you need Light! Why?
Take a look at the below chart. It explains various types of lights and their efficacies.
|T12 tube 4', magnetic ballast||60|
|T8 tube 4', electronic ballast||80-100|
|T5 tube 4'||70-104.2|
T5, T8, T12 are various types of "tube lights". In most households, T12 is used. Number in this notation tells you the diameter of the tube. i.e, T5 tube has a diameter of 5 * (1/8th of inch) = 5/8 inches.
Having electronic ballast (aka chalk) instead of magnetic ballast increases the overall ballast-lamp efficiency by 15-20%. 
What matters ultimately is the light output you get and the month end electricity bill. We'll consider 1200 lumen output, i.e. light output of 1200 lumen and the associated costs. It explains why you should opt for CFL.
- If you are planning to replace your old T12 lamps in your house, choose T8 lamp.
- If you are replacing Incandescent lamps, choose CFL or T8. T8 has a higher efficiency than CFL, but may not be suitable for every location.
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Choose your light wisely. It saves you money and protect environment.