A Generalisable Bottom-up Methodology for Deriving a Residential Stock Model From Large Empirical Databases

Specifying representative reference buildings as a prerequisite for calculating cost-optimal energy performance requirements for buildings and building elements. Appropriate characterisation is prerequisite data for an overall national building energy consumption model to produce valid outcomes. Energy Performance Certificates (EPCs) are issued in the EU, for dwellings whenever they are constructed, sold or leased. Where acquiring data for an EPC would be prohibitively costly, nationally applicable default-values are employed for the building envelope thermal transmittance coefficients. Significant levels of retrofits led to the default-values used now being higher than is typical in reality, leading to characterisations of reference dwellings based on these defaults lacking validity. A methodology is presented for the derivation of simplified default-free inputs to a bottom-up residential cost-optimality energy consumption model from an EPC dataset. 35 reference dwellings (RD’s) are employed to appropriately characterise 406,918 dwellings averaging one RD per 11,626 dwellings. The strong association of dwelling age and energy efficiency has been found to be diminishing as retrofits have been carried out. A view that the majority of dwellings in Ireland are thermally sub-standard may no longer be true