I’ve been a bit grouchy since losing an hour of sleep last weekend for daylight savings time. (Apparently I need my sleep.) But I figured that it was a small price to pay. Not only do I like sunshine more than I like sleep, but the extra hour of evening daylight at night pares back on power bills, right?
Not so fast. A recent study just found that “springing forward” an hour actually increases overall
household energy use. Sure, you might save on evening lighting costs, but you make up for it with higher heating costs in the early morning. And apparently—though I don’t exactly understand the dynamics—shifting the day forward increases the demand for summertime cooling.
The study compared before-and-after energy consumption in Indiana, where until recently daylight savings time was observed only in part of the state. After the whole state started shifting its clocks forward in spring, the authors found clear evidence of a jump in energy use. Studies from the 1970s had suggested that daylight savings time saved on lighting bills—but the authors suggest that, as air conditioners have become more common, any savings on lighting are more than offset by increases in cooling bills.
Perhaps what’s true in Indiana isn’t true in the Pacific Northwest. Still, it shouldn’t be too hard for Northwest utilities to model how changing the clocks affects energy bills in our neck of the woods.
(And by the way, studies also find that changing the clocks on Sunday boosts accidents on Monday. Apparently I’m not the only one who feels groggy after the clocks change.)