Where the electricity in your home goes
The Pew Center on Global Climate Change has just published a few interesting charts on energy use in residential buildings. Here, for instance, is what we tend to use electricity (and, in some places, gas) for in our homes:
And how has energy use changed over time? As the second chart below illustrates, our appliances have become more efficient over the past 20 years. Air conditioners, for instance, which account for a particularly large fraction of summer electricity bills, are getting sleeker. Overall, we’re using less energy per square foot. But that’s been counteracted by the fact that houses and apartments in the United States have kept getting bigger, which means that overall energy use continues to climb:
One hypothesis, advanced by David Owens in The New Yorker last year, is that this is the Jevons paradox in action. As appliances get more efficient, electricity becomes cheaper, and, the theory goes, we then tend to use more of it. If better insulation and more advanced A/C means it costs less and less to heat and cool a given sized home, then why not take the savings to buy a bigger home? On the other hand, economist James Barrett has argued that this paradox is probably overstated—people are getting richer over time, and would be buying bigger homes and using more energy regardless of whether A/C efficiency was improving. That means energy use would be even higher right now if those A/C units and water heaters weren’t getting more efficient.
Either way, those are the trends. As Barrett notes, “The even more interesting question is whether efficiency growth can ever overpower the effect of income growth and start reducing energy consumption in absolute terms.” So far, it hasn’t happened.