It's summer. It's hot outside! And timely new stats from the DOE reveal how one household appliance has blown electricity use through the roof - it's the air conditioner humming quietly in the background, supplying cold air and relief during sweltering afternoons. While that's (duh) common sense, the agency's big news is that the South, abandoning ceiling fans and probably cutting back on iced tea, now relies on the comfort of central air conditioning in a very big way. So much so, that it's become more beloved than NASCAR and zealously "liked" on countless regional Facebook pages.
Rising incomes and central air conditioning
According to the US Energy Information Agency, over the past 20 years air conditioning has increased in all regions of the United States, but it's grown much faster in the South, where, since 1993, electricity "just to cool" sun-baked homes has increased 43% and accounts for (here's the stunning part) 21% of all power used. That's compared to national statistics, where it's increased 39% but accounts for only 14% of all power consumed.
Several factors are responsible, including population growth (the starter chicken that laid this jumbo-sized egg), larger houses, home electronics, and increased reliance on central "air."
Obviously, population and housing are the prime factors. Over the last two decades, as workers relocated from North to South, chasing new industries and jobs, the South added the most new housing, 8.6 million units. But house size can't be overlooked. While floor plans and square footage have gone steroidal across the US for 20 years, Southern homes have bulked up even faster. The average US home may be 5% larger than in 1993, but its beefier Southern neighbor is 9% larger. (There's a science prize, or at least a TedTalk, waiting for the first study that correlates Big hair to Big homes, with blown air as the common thread.)
Since family size has dropped across the US, increasing incomes and architectural fashion have caused new Southern homes to be 11% larger than in the 90's, and 42% larger than in the 80's. This insures that, like up North, McMansions have sprouted up over former shotgun shacks and post World War Two starter homes in suburbs below the Mason Dixon line.
The energy hog
Now this is where the EIA's data drill-down pays off: the increase in "cooled area" has grown at the same rate as size, 14% and 50%, since almost all new homes in the South have central air conditioning.
And that sets up the bad news: central air conditioners usually consume more energy because they cool more area in the home (pets are most thankful for this). In 2009, homes in the South with central air conditioning used an average of 3,382 kilowatthours per year (kWh/year), and nearby homes with room units only used an average of 1,882 kWh/year for air conditioning. That's a convenience-spread so big you could drive a Zamboni through it.
Because differences in income determine air conditioning use, in the South, 8% of households with the lowest incomes do not use air conditioning and 25% use only room air conditioning.
By contrast, only 1% of southern McMansion owners eschew air conditioning, and only 3% settle for room air conditioning. So although most households in the South use central air conditioning, the households not using it are largely those with the lowest incomes, living in much smaller homes. So remember, when boosters say that everything is bigger in Texas, that may be true, but unfortunately, it also includes bigger air conditioning bills too.