This paper summarises the results of a combined numerical, statistical and experimental study concerned with the use of dissimilar walling systems on the external parts of a given building envelope. The rational behind this “hybrid wall” concept, as opposed to conventional approaches where identical walls are used in a building envelope, is to achieve a more effective distribution of thermal mass across the envelope and, hence, improve the overall thermal performance of the building. The effectiveness of the “hybrid wall” concept was investigated using a series of hypothetical building modules of common Australian residential constructions, namely Light Weight (LW), Brick Veneer (BV), Reverse Brick Veneer (RBV) and Cavity Brick (CB). These designs were examined numerically using a commercial energy rating tool known as “AccuRate”, statistically using JMP software and experimentally using a novel bench-scale setup developed as part of this study. The performance of each design was evaluated by its energy consumption. The numerical predictions and experimental data highlighted that the east and west walls have the most impact on the energy consumption under Australian climatic conditions. It was found that considerable reductions in the energy consumption could be achieved in cases where the hybrid wall concept was implemented through the use of high thermal mass insulated walls on the east and west sides of the building envelope.