Just notice it here in California, right at midnight. Whew! Very dramatic.
Also to be considered...
The hardware stores here (in California) have been selling compact fluorescent bulbs for less than a dollar apiece for a while now. They're far better than fluorescent bulbs were a few years ago, and I'm putting them in wherever I can. Try them... you'll like them.
I also turn off my computer at night, something I didn't used to do.