The document compares the building materials and embodied energy consumption of an old 150-year-old Kolkata Municipal Corporation building and a modern Technopolis office building in Kolkata. It finds that the old building used lime mortar and lime concrete instead of cement and iron beams instead of steel. It calculates the quantities of bricks, lime, iron, and glass used in the old building and estimates their embodied energy. A similar analysis is done for the modern Technopolis building which extensively uses cement, steel, bricks, and glass. It is found that the embodied energy of iron/steel is 3.18 times more and of cement is 5.47 times less in the modern building compared to the old building per square meter