According to the container recycling institute, nearly a million plastic beverage bottles are sold every minute around the world. Plastic bottles are considered as an urban junk, however, it has shape characteristics which make them usable in construction in lieu of conventional bricks. This research promotes the use of recycled plastic bottles as eco-bricks by substituting it with the typical construction bricks. It evaluates the thermal performance of sand filled plastic bottle-walls in a comparative analysis with traditional composite brick walls.  The thermal performance of the plastic bottle walls was evaluated through COMSOL® Multi-physics and the results are noted.