In the U.S., green building can mean a lot of things — recycled greywater, roof gardens, solar panels and the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) certification all come to mind. But in Europe, many green builders focus laser-like on the amount of energy a building consumes, half of which typically comes from heating and cooling. Twenty years ago, German physicists erected a home that demonstrated how little energy a building would need if built with, among other things, thick insulation and airtight walls. The so-called “Passive House” (or “Passivhaus” in German) was soon replicated throughout the continent. I learned about the concept when I met building scientist Henry Gifford — a persistent critic of LEED certification and noted leader of the New York City “Boiler Tour” — while researching a story on green building in Manhattan’s East Village. In the same way that I feel the ‘organic’ label doesn’t necessarily mean a food was produced in the most sustainable manner, it seemed the term “green” was often misleading when applied to buildings. But Gifford’s Passive House projects seemed like the real deal – no bells and whistles, just slashing energy use with some simple principles. I embarked on a documentary project to show how far Europeans have taken the concept and to show the pioneering American builders who are bringing the movement across the Atlantic. The result was “Passive Passion,” a documentary selected for the 2011 Architecture and Design Film Festival. See clips from Charles Hoxie’s documentary, “Passive Passion.” Today, there are tens of thousands of Passive Houses in Europe, mostly in Germany and Austria. To attain the label, buildings must hit benchmarks for energy use and air tightness, and Europeans apply the standard to just about every construction imaginable – homes, apartment complexes, schools, gymnasiums and others. These buildings share one trait: they use about 90 percent less energy for heating and cooling than a traditional structure. But virtue isn’t the main selling point, according to Wolfgang Feist, the physicist who founded the Passivhaus Institut in Darmstadt, Germany. “You really get a very comfortable home,” says Feist. “With no noise, with no drafts… and with a very high indoor air quality. This is I think the most important thing. And you get all of this with a very low consumption.” A Passive House is quiet because thick walls and windows cancel out the din of the city and the late-night guitar noodling of neighbors. But perhaps even more noticeable is the difference in air quality. Although they are designed to be airtight, Passive Houses typically have advanced ventilation systems that constantly pump in fresh filtered air. And unlike traditional homes, which are like Swiss cheese by comparison with the airtight Passive Homes, all of the air coming in gets filtered. The stale air transfers its heat or cool to the fresh air, further increasing the home’s efficiency by avoiding thermal losses. All of this results in an indoor air quality akin to stepping out of your car after driving from the city into the country. “It’s like being outside, but inside,” says Katrin Klingenberg, the founder of the Passive House Institute of the United States. Fresher air also could mean healthier lungs. The filters remove particulates and pollen, as well as other potentially hazardous pollutants, like off-gassing from carpets or furniture. In the U.S., Passive House building is still the domain of enthusiastic “true green” builders, but increased demand could lead to cheaper components, pushing the price tag down and amplifying interest even further. And that might improve the planet’s health as well as our own. Top image: The Hudson Passive House designed by Dennis Wedlick Architect. Courtesy Flickr user BASF Subscribe to Txchnologist’s daily email. Charlie Hoxie is a documentary filmmaker based in Brooklyn, NY. For more information on the documentary ‘Passive Passion’ visit www.charliehoxie.com.