Where to save energy

This article about the savings from compact fluorescents is pretty good. It's really about the interaction between all your electrical appliances and the rest of your energy consumption.

The basic message is that electrical appliances heat your home; all the energy you "consume" running appliances and lighting is really converted into heat that gets dumped into your home. If you want to heat your home, this is a side benefit—so reducing your electricity consumption under those circumstances doesn't save as much in fossil fuel consumption, greenhouse gas emissions, energy costs, etc. as you might think, because you'll be running the furnace a little more. It does probably save some, because electric resistive heating is not the most efficient way to heat your house; but less than a naive calculation would imply.

On the other hand, if it's hot and you're running the air conditioner, the analysis turns upside down, and there's a large multiplier attached to any energy savings from more efficient (or less-used) appliances and lighting, because you'll have to work to pump that heat back out of your house. In that case, switching to fluorescents could save you a lot, and reduce your carbon footprint correspondingly.

And in either case, making your home more efficient at retaining the temperature you want is a big, big win.