Meeting the 2011 zero carbon buildings target for Wales using the Passivhaus standard

The Welsh Assembly Government has stated that from 2011 all new buildings in Wales must be ‘zero carbon,’ five years ahead of the 2016 deadline set for homes in England. When policy makers and politicians set such goals they are often unaware of the technical, social and economic difficulties in achieving them. If the Welsh construction industry is to deliver on these promises, it urgently requires low or zero carbon standards and solutions that can be scaled up to meet increasing demand for new housing. The Passivhaus standard is enjoying a growing popularity on continental Europe, particularly in Germany and Austria, and although it does not satisfy zero carbon definitions, it could provide a useful starting point from which to develop low or zero carbon buildings. Its main premise—that “design heat load is limited to the load that can be transported by the minimum required ventilation air”—captures the essence of the approach in a way that is tangible and easily grasped by the imagination. This paper reports on research on the Passivhaus standard as a basis for new low carbon housing in Wales by examining the standard for its appropriateness in the milder Welsh climate, considering the construction technologies required to satisfy the standard, and considering the implications of applying the standard in Wales. The research concludes that Passivhaus offers a useful starting point but there is uncertainty about its dynamic thermal stability, the demands it places on occupant operation and requirements for high standards of construction skills