Charlie Komanoff, one of the smartest people I know, has written an excellent post on how to think about energy efficiency:
On the face of it, doubling the efficiency of clothes washers and dryers shouldn’t cause the amount of laundering to rise more than slightly. But consider: 30 years ago, an urban family of four would have used the washer-dryer in the basement or at the laundromat, forcing it to “conserve” drying to save not just quarters but time traipsing back and forth. Since then, however, efficiency gains have enabled manufacturers to make washer-dryers in apartment sizes. We own one, and find ourselves using it for “spot” situations — emergencies that aren’t really emergencies, small loads for the item we “need” for tomorrow — that add more than a little to our total usage. And who’s to say that the advent of cheap and rapid laundering hasn’t contributed to the long-term rise in fashion-consumption, with all it implies for increased energy use through more manufacturing, freight hauling, retailing, and advertising?
I imagine Jim Manzi will object to Charlie’s conclusion:
The antidote to the Jevon paradox, then, is energy taxes.
But the post is well worth your time regardless of where you come down on the carbon tax question.