Cascadia Scorecard News
September 2005

As far as North American home buyers are concerned, the prevailing attitude seems to be bigger is better. The average size of a new single-family home in the US has more than doubled since the 1950s, from 1,100 square feet to 2,340. At the same time, families have gotten smaller: the average household now has 2.6 members, down from 3.7 at the height of the baby boom. Combining these two trends-larger houses and smaller families-new homes today have three times as much living space per person than did the homes our grandparents bought. Trends in Canada are similar, though less extreme.

Obviously, larger houses require more building materials than smaller ones, a problem compounded by trends towards higher ceilings and complex designs such as extra wings. Larger homes, along with patios and decks, also generate more storm water runoff, which can tax sewer capacity and harm streams. And not surprisingly, big houses also require more energy to heat and cool than smaller ones.

The homebuilding industry has become greener in some ways over time. Homebuilders and have learned to use building materials more sparingly; and the materials themselves require less energy and raw materials to manufacture than they did two generations ago. And more importantly, new heating and cooling systems have grown steadily more efficient; many new homes are better insulated than the ones from years past.

Still, these gains in energy efficiency are being overwhelmed by the trend towards supersized houses. A recent study estimated the heating and cooling costs for a small, poorly insulated house and a well-insulated house twice as large, finding that the small house still used almost a third less energy. Apparently, even a "green" home isn't green if it's too big.

Some "green building" certification programs do take size into account. Portland's Earth Advantage rating system for new homes awards extra points for houses less than 2,000 square feet, and even more for houses less than 1,500 square feet, in the categories of resource efficiency and environmental responsibility.

Building more green homes helps stimulate the market for more green materials and building techniques. But building smaller green homes can magnify that good, by using technology to significantly reduce our impact on the environment. And ultimately, it's up to us to build living spaces that are better, and not merely bigger.

Resources for building better spaces

The Not So Big House website
Northwest EcoBuilding Guild (US Northwest)
Earth Advantage (Portland)
Built Green (Seattle)
Built Green Washington (Washington State)
Canadian Green Building Council
US Green Building Council