Passive solar design is an architectural approach that utilizes natural sunlight to heat and light buildings without relying on mechanical systems. This design focuses on strategic placement of windows, walls, and floors to capture and store solar energy. Key elements include orientation, thermal mass, and insulation, which work together to maintain comfortable indoor temperatures throughout the year. By maximizing sunlight exposure during winter and minimizing it during summer, passive solar design can significantly reduce energy consumption. This method not only lowers heating and cooling costs but also contributes to environmental sustainability by decreasing reliance on fossil fuels and reducing greenhouse gas emissions.