A new Pew report looks at how the growing size of American homes affects energy efficiency:

U.S. homes have become considerably more energy-efficient over the past four decades, according to government data. But homes also are a lot bigger than they used to be, and their growing girth wipes out nearly all the efficiency gains.

According to preliminary figures from the Department of Energy’s Office of Energy Efficiency and Renewable Energy, the average U.S. home used 101,800 British thermal units (Btu) of energy per square foot in 2012, the most recent year with available data. That’s 31% less than in 1970, after adjusting for weather effects and efficiency improvements in electricity generation…

While some homeowners do add onto their existing structures, the trend is driven largely by new construction. According to the Census Bureau, the average new single-family house completed last year was 2,657 square feet – 57% larger than four decades earlier. While the biggest new homes are being built in the South (an average of 2,711 square feet last year), home sizes have grown the most in the Northeast: a 64% increase in average new-home size over the past four decades…

What all of this means is that, after dropping sharply during the 1970s, the overall energy intensity of U.S. homes has changed little over the past three decades. Energy intensity is a metric that compares the amount of energy used against some unit of economic activity – households, in the case of the residential sector.

A logical question at the end of this is to ask what should be done in response. One line of argument would suggest Americans should cut their home size. When they build and purchase larger homes, they use more energy than they probably need to consume. (This is in addition to other arguments against building larger houses.) On the other hand, I imagine some would argue that we will continue to see gains in energy efficiency through technology and this will soon reduce energy use even in spite of larger homes. This second argument may be more appealing to many as then Americans could get even bigger homes and we get to utilize the benefits of technological progress.