There are a lot of reasons why green building is _suddenly_ a big deal Sustainable building isn’t exactly a new phenomenon, but it has certainly taken root in a way that earlier efforts to change residential construction did not. Chalk it up to the coalescence of many things.

Energy costs are one key. The frenzy in passive solar design that began with the energy crunch of the 1970s fizzled when fuel prices declined. We lost a powerful incentive to build more-efficient houses that were cheaper to heat and cool. Building energy efficient houses was pushed to a side rail and forgotten. But now that energy prices have gone back up, we have a much better understanding of how tenuous our foreign supplies of fossil fuels have become. Global climate change is another factor. Melting glaciers, disappearing Arctic ice, droughts and fierce storms—we’ve all read about them, and many of us have experienced them firsthand. Researchers attribute at least some of these phenomena to a gradual increase in greenhouse gases, which is causing the planet to warm up. Houses are part of the climate-change equation because they consume a great deal of energy. So when scientists talk about our “carbon footprint,” we now have a direct correlation between what we do and the world around us. We know more about how houses work than we used to. Building scientists who study the mechanics of why houses behave the way they do have helped promote designs that are more durable, more comfortable and healthier than conventional houses. This increased technical prowess has made it possible to apply sensible building practices to all kinds of architectural styles. Finally, the time was right for a shift in thinking. Just as Sarah Susanka struck a nerve with her “Not So Big” approach to residential design, proponents of sustainable building have made their case at just the right time. Homebuyers are apparently ready for a change, and the building industry is ready to follow. The fact that green-built houses last longer, have fewer problems, are cheaper to live in and keep their owners more comfortable—well, that doesn’t hurt.