Traditional clay bricks are the most prevalent filler material used in construction in India. The materials used in building have a considerable impact on the built environment as well as the final cost of the project. The use of autoclaved aerated concrete (AAC) as a feasible alternative to clay and fly ash bricks has lately gained popularity. A comparison of clay bricks and AAC blocks is investigated in this paper. Even though AAC blocks have been used in construction since 1924, they today account for just 16-18% of total construction in India. Because of its low bulk density, superior thermal and acoustic characteristics, lightweight, and simplicity of installation, AAC blocks are an apparent replacement for traditional clay bricks. The goal of this research is to show that AAC blocks have the potential to replace clay bricks as an infill material and to encourage their use in construction to generate more energy-efficient and sustainable constructions. The potential of AAC blocks as an infill material in hilly terrain is examined.