A 7 star house has less artificial heating and cooling requirements and hence, emits less greenhouse gas emissions. Also, homeowners of a 7 star house pay less energy bills compared to a 6 star house. As a rule of thumb, a 7 Star house requires 19% less heating and cooling compared to a 6 Star house.
NCC 2022 requires all new dwellings to achieve a 7 star energy rating, succeeding the older version, which required a 6 star energy rating.