Since its inception, the US population has progressively migrated westward. And more recently, thanks to the advent of air conditioning, we’ve moved southward. These trends, according to new data from the U.S. Energy Information Administration (EIA), have decisively shaped residential energy consumption patterns in recent decades.
The EIA’s data release suggests that our geographic shifts have been associated with a relocation toward warmer conditions, which has in turn meant lower demand for energy-intensive home heating. This phenomenon has been an important factor in dampening per capita energy consumption over the past 50 years – even as the average home’s square footage has been increasing.
The map below gives a sense of Americans’ westward and southward migration over time: in 1790, the country’s so-called “mean center of population” was in Maryland; in 2010, it was situated in southern Missouri.
While in 1960, only 31.2% of the U.S. population lived in the warmest states (as defined by a temperature measurement called degree days), this share of the population rose to 43.4% by 2010. On the other hand, the share of the population living in cooler states declined from 59.7% in 1960 to 48.3% in 2010.
The shift toward warmer climates has naturally entailed greater demand for air-conditioning. But because space heating generally requires more energy than space cooling, the total residential energy load from heating and A/C has actually gone down since 1960, as heating needs have decreased relative to cooling needs.
This isn’t to say that warmer is necessarily better for the world’s energy future. The recent spike in air-conditioning load in the US and internationally—due to a combination of intense summer temperatures and a greater ability of developing-nation households to afford air conditioners—has the potential to put strong upward pressure on residential energy demand in the coming years.