What is a benefit of higher ceilings in tropical passive cooling design?

• A. They increase energy use for cooling
• B. They create a larger volume for buoyant air, reducing stratification
• C. They increase glare
• D. They decrease airflow

Answer: (B)

In tropical passive cooling, the goal is to move heat out of the space using natural air flow created by buoyancy. Taller ceilings expand the vertical space for warm air to rise, which strengthens the stack effect. With more room for buoyant air, the hot layer can rise toward roof-level openings and exhaust, while cooler outside air can be drawn in at lower levels to replace it. This reduces stratification, meaning the temperature difference between the top and bottom of the room is less pronounced, so occupants feel cooler without mechanical cooling. That’s why higher ceilings are advantageous for passive cooling. The other options aren’t benefits: increasing cooling energy use conflicts with passive cooling, glare and airflow changes aren’t inherently improved by height alone and depend on other design details.