You used to be able to predict how much energy a home would use, just based on how big it was. Either heating or cooling took more energy to change the temperature of a larger space.
We can’t do that anymore. Homes increased in size from 1,800 square feet when built in the 1980s to 2,465 square feet when built in the 2000s (remember when we built houses?)
Not only did they get bigger, but the ceilings got higher as well, meaning there was more air to condition. Just 17% of homes built in the 1970s had ceilings higher than 8 feet, but 52% of homes built in the past decade did.
So what happened to energy consumption? It dropped–dramatically, from 127 million BTUs per household annually to 90 million.
It’s not because everybody moved back in with mom and dad, either. The largest segment of households had 2 people only.
What’s happening is that energy consumed per square foot has dropped as house size has grown. Small and older houses use a lot of energy–sometimes three times as much per square foot as larger, more modern houses.
Energy efficiency is being incorporated into new buildings and it is working. We’ve grown from 80 million houses to 117 million and are using the same amount of energy. We’ve grown from 226.5 million souls in 1980 to 308 million in 2009–and it isn’t taking any more energy to house us.
Good for us.