We supported the transition to low carbon domestic heating by quantifying the thermal behaviour of a representative dwelling and the effects of fabric measures and emitter and control strategies. Computational fluid dynamics and targeted experiments were combined to characterise infiltration pathways, internal convective plumes and room to room coupling under realistic occupancy and operating schedules. Scenarios included heat pump compatible flow temperatures, radiator sizing and placement, underfloor heating alternatives and insulation upgrades. Metrics included room temperature uniformity, warm up and recovery times, surface temperatures for comfort and condensation risk and energy use proxies. Verification and sensitivity checks on mesh resolution, turbulence near walls and infiltration assumptions provided robust relative comparisons. The results distilled practical measures to cut heat demand and to enable efficient low temperature operation, with clear next step guidance for demonstration and monitoring at the Salford Energy House facility.