How much energy do lights use?
The diagram below shows a picture of a slankey diagram. Energy is weighed in kj (kilo joules). the electrical energy represents how much energy you started with. The light energy represents how much energy you used for the lights. The heat energy represents how much energy you did not use for the lights but you used it for heat.
Turning off the lights does not actually save energy; energy not burned by the lights is simply run into the ground. It will save you $$, but not save energy. However, turning off the lights does send a market signal to electricity producers, informing them that current electricity production is too high (because it is being wasted) and decreasing future loads. Conserve energy? It completely stops the use of it. How much more can you conserve? update: Hopefully the person above is taking their own advice and not voting or reproducing :-) "It completely stops the use of [energy]?" No, it stops your use of it, but the energy company still burns it if you don't use it. Only when we stop using it on a large scale does the energy company not produce as much, and we then save. Turning off that light right now? Earth hour? Not saving the planet or any energy. Only if we do it ALL THE TIME.