By combining biochar's insulation properties with phase-changing materials' (PCMs) energy storage capabilities, these systems aim to revolutionize energy consumption and indoor climate regulation. Biochar, derived from organic materials through pyrolysis, offers multifaceted benefits, including waste reduction, carbon sequestration, and improved soil conditioning. The impregnation of PCMs into biochar enhances thermal properties, energy storage efficiency, and temperature regulation in buildings and agricultural soils. These composites contribute to a circular economy by repurposing waste products and aligning with sustainable principles. Overall, PCM-biochar composites show promise in addressing challenges in sustainable energy and environmental management, offering versatile solutions across various sectors. This review explores the integration of PCMs with biochar for sustainable and energy-efficient building solutions.