The article reviews how adding special materials to building walls and roofs can help save energy and reduce CO2 emissions. These materials, called phase change materials (PCMs), store and release heat more efficiently than regular building materials. By using PCMs in building components, like walls and roofs, energy consumption can be reduced, especially in lightweight construction. This method is effective for cooling and heating buildings without using a lot of energy. The research aims to help design energy-efficient buildings in different climates by analyzing how these materials can be integrated into building elements.