The University of New South Wales has analyzed the use of surplus rooftop solar for residential pre-cooling and pre-heating across four Australian cities. Using hourly data from 450 households and AccuRate simulations of nine building types, the study evaluated the impact of solar pre-conditioning on electricity demand and emissions. AccuRate, developed by CSIRO, simulates hourly thermal behavior and estimate heating and cooling loads, assigning efficiency ratings from 0 to 10 stars. Findings showed that solar pre-conditioning reduced minimum daytime demand by up to 4 kW and evening peak demand by up to 0.8 kW per building without compromising thermal comfort. In Brisbane, a 6-star rated home achieved annual CO2 reductions exceeding 600 kg. Seasonal analysis revealed up to 30% emission cuts during summer and spring, especially in grids with high solar penetration.