Thinking green? It's not just black and white.

By Katherine Salant
Saturday, August 21, 2010

Can a big house be green?

Yes, but a smaller house will always be greener because fewer resources were used in its construction and less energy is needed to heat and cool it.

This critical distinction is little understood by the general public, but in the world of green building, prudent use of resources, also called "sustainability," is a cornerstone. It means using resources to meet our needs without compromising the ability of future generations to meet their needs. From a green perspective, the fewer resources and energy used the better.

The number of different resources tapped for homebuilding is relatively small, but their quantity is staggering, even for a modest-size house, said Dan Chiras, author, educator and director of the Evergreen Institute in Gerald, Mo. To build a 2,200-square-foot house, an acre of forest will be clear-cut somewhere on the globe and a huge hole in the earth, roughly equal in size to the volume of the house, will be excavated to provide the raw materials that go into copper, aluminum, steel and concrete. A house that's twice as big (4,400 square feet) will require about two acres of clear-cut forest, and a much bigger hole. Homeowners could more readily connect the dots between greenness and house size if this information were more widely available, but most green building programs do not provide a way to make comparisons between houses of differing sizes, said Michael Horowitz, a green building expert based in Marshfield, Vt. When size is addressed, it's usually done obliquely; to qualify as green and earn a higher rating, you have to do more things as the house size increases.

In programs that focus solely on energy consumption, such as the government's Energy Star Homes program, energy efficiency is calculated by comparing houses of the same size. A house gets the Energy Star rating if it is 15 percent more efficient than the same sized house built to the model energy code standard.

A better way to rate houses -- and one that would illuminate the gross differences in material and energy consumption between large and small houses -- would include occupancy in the formula, Horowitz said. He proposes a scoring system that rates the greenness of a house by the amount of material and energy used per occupant, which is assumed to be the number of bedrooms plus one.

Graphically describing what this might look like, Horowitz compared his own modestly sized, 1,800-square-foot, three- bedroom house with four occupants with another home that is three times as big, carrying a higher green rating and housing the same number of occupants. "First," he said, "divide all the materials used to build my house into four piles in my driveway and then added a visual to each pile that would show how much energy each of us used per year. The size of the piles would be impressive. But when you do the same thing for the bigger house, the size of its four piles would dwarf mine."

By this method of accounting, however, the bigger house would receive the same rating as Horowitz's if 12 people lived in it instead of four.

If the inherent greenness of smaller houses were well understood, would the American public opt for them? "Bigger is better is a sacred cow in the U.S.," Chiras said, and in our culture, nothing telegraphs personal success like a really big house.

Preaching the virtues of a smaller house is not impossible, however. Although the culture at large may be caught up in the "bigger is better" syndrome, individuals can be persuaded to downsize "if you catch them early on, before they have purchased land or become fixed on size," said architect and green building advocate Peter Pfeiffer. But, he added the winning argument is not greenness, it's lifestyle.

Many people who aspire to the simple life want to build a big house in the country, without realizing that it will actually make their life more complicated, Pfeiffer said. They don't factor in how much of their day will be spent in the car. A bigger house has other baggage as well. It will be more costly to furnish and maintain and more time-consuming to clean. In contrast, Pfeiffer said, a smaller house within city limits offers independence for the kids at an early age -- they can walk or bike to school. It's a 10-minute commute to work, and weekends and evenings can be spent socializing with family and friends, not housecleaning and looking after those four acres of rolling countryside.

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