Stack Effect occurs when the air inside a building is heated and becomes less dense than the air outside. The taller the building, the

Stack Effect occurs when the air inside a building is heated and becomes less dense than the air outside. The taller the building, the

• A. weaker the effect becomes
• B. it diminishes
• C. the stronger the effect becomes
• D. no effect

Answer: (C)

Stack effect is the buoyant rise of warmer indoor air and the pull of outdoor air to replace it. When indoor air is heated, it becomes less dense and moves upward, escaping at the top while cooler outdoor air is drawn in at lower levels to take its place. The driving force behind this flow is a pressure difference that grows with height—the weight of the air above creates more pressure difference as you go higher. Because of this, the taller the building, the greater that pressure difference and the stronger the stack effect. In practical terms, taller buildings tend to have more air movement: more infiltration at the lower floors and more exfiltration at the upper floors, leading to greater energy loss and potential comfort issues unless addressed with sealing and proper ventilation strategies.

Stack effect is the buoyant rise of warmer indoor air and the pull of outdoor air to replace it. When indoor air is heated, it becomes less dense and moves upward, escaping at the top while cooler outdoor air is drawn in at lower levels to take its place. The driving force behind this flow is a pressure difference that grows with height—the weight of the air above creates more pressure difference as you go higher. Because of this, the taller the building, the greater that pressure difference and the stronger the stack effect. In practical terms, taller buildings tend to have more air movement: more infiltration at the lower floors and more exfiltration at the upper floors, leading to greater energy loss and potential comfort issues unless addressed with sealing and proper ventilation strategies.