We hope this helps. When you go to the store to buy light bulbs you check to see the number of Watts on the package. You know that a 75 Watt bulb will let you see comfortably and a 150 Watt bulb might be better for reading. Unfortunately, the Watt is a poor measure of how bright a bulb is. Watt refers to how much electric power goes into the bulb, not how much light comes out of it.
Some bulbs are much more efficient at making light from the same amount of electricity.
You can t compare watts directly and know much about brightness, only if it will burn out your lamp fixture. Light Bulb manufacturers have been struggling with this as they have begun to sell more efficient bulbs. You will notice that bulbs now have rating in Lumens. A lumen is a measure of how much light energy a bulb emits. You can see why energy conservationists promote the use of flourescent lights - they are very efficient.