In the article 'First Steps: What can be a passive house in your region with your climate?', Wolfgang Feist of the Passive Institute in Germany, advises that passive house details must be specific to individual climatic and geographical regions especially considering the local building traditions and climatic conditions. He highlights examples of applying Californian passive solar design principles to buildings in central Europe resulting in buildings which were designed for large solar gains that did not exist.
He proposes that the 'Zero Energy House' concept would add an unacceptable cost to a project as he sees no extra benefit being gained by increasing efficiencies beyond the 10W/m2 target. He maintains that the environmental impact is minimal even considering the use of fossil fuels including oil, gas or coal as the energy demand is so low throughout the lifespan of the project.