This position paper introduces a methodology for the novel application of post-occupancy evaluation (POE) data with the aim of proactively reducing operational performance errors in sustainable domestic construction through better materials selection. The theory is based on the premise that a significant gap exists between the actual physical performance characteristics and the design predictions of sustainable dwellings. This gap is quantifiable through POE, such as co-heating tests which measure the heat loss coefficient of an entire dwelling, post-construction allowing comparison against the UK’s Standard Assessment Procedure (SAP) design values. The proposed methodology suggests that this gap is proportionally different for housing constructed using different materials and different fabrication methods, given a standard air tightness. A proportionally smaller gap between design and actual performance of housing built using a particular fabrication method would indicate a more accurate method of construction. Subsequently if one construction method is found to have a proportionally smaller gap, it would suggest that future developments should possibly use the more accurate material as the basis for their construction in order to achieve compliance.