And sometime, the difference may be neglictible but the whole idea behind is more important.
Yeah, sorry, that's stupid. If we're supposed to be optimizing stuff, why are we wasting energy doing something for the "idea" of it if the numbers don't work out? Isn't that the exact opposite of the whole point?
ok then, leaving the lights on when you dont need it is a big deal so, lets do it. Do you shut it off to save few pennies? When you say "don't work out" you mean "not enough to bother" or "result is the oposite of what I think it should be"?
Both. You're forgetting that everything has a cost. Comfort, time, etc.
I turn the lights off when I leave the room. Over a year, or a month, it can add up. I don't turn the lights off when I'm going to be back in the room in a minute or two, because the switches are really inconvenient. The 30* seconds extra to go turn off the lights and then turn them on when I get back is not worth it for me; I just leave them on. That would add up to probably a dollar a year saved on my electric bill with the lights that I use (currently all CFL in that room), so I don't turn them off if I'll be back in that room within 5 minutes.
Similarly, for me (and probably Chris) the cost of having the AC on at a stoplight was for me maybe an extra half gallon a tank. If that. $2 a month for 3 months for added comfort and not showing up to my destination covered in sweat? Yeah, that is worth it, and the result is the opposite of what I expected--it costs me more to have the AC off than on. I value my comfort pretty highly once my clothes are on the verge of getting wet.
*It really is 30** seconds to turn on/off the lights in my bedroom right now. That is a temporary thing; I am moving into the place and the room is a mess of boxes around a bed. I can't get to the light switch.
**Ok, probably only about 10 or 15. Still, really annoying.