Analysis from EIA's most recent Residential Energy Consumption Survey (RECS) shows that U.S. homes built in 2000 and later consume only 2% more energy on average than homes built prior to 2000, despite being on average 30% larger.
Homes built in the 2000s accounted for about 14% of all occupied housing units in 2009. These new homes consumed 21% less energy for space heating on average than older homes (see graph), which is mainly because of increased efficiency in the form of heating equipment and better building shells built to more demanding energy codes. Geography has played a role too. About 53% of newer homes are in the more temperate South, compared with only 35% of older homes. Read more.