What do dieting and energy policy have in common? The SnackWell effect. The name comes from those tasty little cookies that are advertised as being lower in fat and sugar. And they are--which often leads dieters to eat more of them than regular cookies and then wonder why they're not losing weight.
It turns out there's a SnackWell effect for energy use too--and it may make it tougher for us to cut back on carbon. When environmentally conscious consumers buy an energy-efficient dishwasher, for example, they may feel less guilty about running the machine more often and as a result may not end up saving much on their utility bills. Likewise, studies indicate that people who install more-energy-efficient lights lose 5% to 12% of the expected savings by leaving them on longer.
Much like dieters eating too many SnackWell's, we can hamstring our attempts to save energy and money. So resist the urge to raise your thermostat after you buy a more efficient furnace; lower the temperature by a degree and shave another 1% off your heating bill.
But even if we do what Jimmy Carter did and wear a stylin' '70s sweater all winter, we may end up spending those energy savings somewhere else--like on a plane ride to Bermuda. Although studies are scant, a 2007 report by the UK Energy Research Centre estimated that globally, this rebound effect could reduce the savings from energy efficiency by 10% or more.
That doesn't mean energy-efficiency measures are useless--or that we should never go on vacation. But it does mean that cutting back on energy consumption, like dieting, is not an excuse to gorge ourselves on less guilty pleasures.