51 Ways to Save the Environment 6. Ditch the Mansion

Oversize houses aren't just architecturally offensive; they also generally require more energy to heat and cool than smaller ones, even with efficient appliances. And in the U.S., big houses are becoming the norm, even though a relatively inefficient small house consumes less energy than a greener large house and uses fewer building materials, which expand the carbon footprint. A typical new single-family home in the U.S. is nearly 2,500 square feet today, up from about 1,000 square feet in 1950, even as the average household has shrunk from 3.4 to 2.6 people.