The Earthizenz residence–office demonstrates the use of Hydraform interlocking block technology for sustainable housing. Blocks were manufactured on-site using locally excavated soil and later fly ash sourced from a nearby coal-based power plant. The house provides excellent thermal comfort, reduced energy consumption, minimal maintenance, and an aesthetically pleasing natural finish, showcasing the potential of fly ash-based interlocking masonry for energy-efficient and environmentally sustainable homes.