And of course, the 5-7% differential comes down to economies of scale:Using ultrathick insulation and complex doors and windows, the architect engineers a home encased in an airtight shell, so that barely any heat escapes and barely any cold seeps in. That means a passive house can be warmed not only by the sun, but also by the heat from appliances and even from occupants' bodies. And in Germany, passive houses cost only about 5 to 7 percent more to build than conventional houses.
Germany and Denmark jump started their green industries with government subsidies and high gasoline taxes. The world will go to Germany for heat exchangers as it does to Denmark for windmills. Meanwhile, our traditional strengths of innovation and entrepreneurship are being bled away thanks to short-sighted thinking.In Germany the added construction costs of passive houses are modest and, because of their growing popularity and an ever larger array of attractive off-the-shelf components, are shrinking. But the sophisticated windows and heat-exchange ventilation systems needed to make passive houses work properly are not readily available in the United States. So the construction of passive houses in the United States, at least initially, is likely to entail a higher price differential.