The significance of Earth Hour isn't necessarily the amount of energy saved but more that it raised such a great level of awareness and participation. Though to be honest, I am not overly impressed with the savings of 7.7%. In general I think that homeowners are conscious of their energy use, particularly over the last few years with rising energy prices. I suspect that if Earth Hour was run 2, 5 or 10 years ago, the impact would have been much greater in energy savings. Homes are increasingly more energy efficient and there is a move away from the use of the incandescent light bulb. In fact, our household only uses energy efficient bulbs.
If an 8% savings means we live in the dark at home, it is apparent that while homes can have some positive impact, we need more attention on what the true energy hoarders are. What I would like to see is a breakdown of the other 92.3% energy consumption. I think everyone would find a few surprises; one being that homeowners are not the primary cause.
I'm not trying to put a downer on Earth Hour as I believe it was a great initiative, we just don't deserve a well-done 'pat on the back' quite yet.