Natural ventilation is the process of using outdoor air to improve indoor air quality and regulate temperature without relying on mechanical systems. It occurs through openings like windows, doors, and vents, allowing fresh air to flow in while stale air exits. This method can help reduce energy costs and create a more comfortable living environment. This technique is often enhanced by building design elements such as cross ventilation and stack effect. Cross ventilation occurs when air flows through a space from one side to another, while the stack effect utilizes temperature differences to draw air upward, promoting circulation.