Application and limitations of regional and future predictive climate data in passivhaus design

According to the Passivhaus Institute (PHI) the verification of a Passivhaus design must be carried out using the Passivhaus Planning Package (PHPP). A number of methods are now available for designers to access climatic data for use in PHPP design predictions. The original climate data provided for design and certification in the UK was derived from the reverse engineering of TRY data from dynamic simulations, for a limited number of locations.  The following research examines the need for regional and, in some cases, micro-regional climatic data when designing ultra-low energy Passivhaus buildings in the UK. The paper proposes a new methodology for generating this data in PHPP format based on the UKCP09 climate projections. The data generated is compared to alternative sources, and the implications discussed in a case study of a certified Passivhaus dwelling in Wales.