What benefit does keeping cold aisle doors closed provide in data center cooling?

• A. Maintains pressure/airflow, improves cooling efficiency, and protects thermal budget.
• B. Increases energy consumption.
• C. Reduces the need for cable labeling.
• D. Seals the rack against dust.

Answer: (A)

Closing the cold aisle doors creates a contained, defined path for cold supply air and hot exhaust. This containment keeps the cold air from mixing with hot air and preserves the pressure differential that drives the intended airflow, so cold air reaches server intakes efficiently while hot air exits through the hot aisle. With this separation, cooling devices operate more effectively, allowing heat to be removed with less energy and maintaining temperatures within the targeted range—the thermal budget. In short, the doors help maintain airflow efficiency and cooling performance.

The other options don’t reflect the main benefit: closing doors does not inherently increase energy usage, it doesn’t relate to cable labeling, and while it can reduce dust ingress, that’s not the primary cooling advantage described.