Recommended environment: 20–24 °C and 45%–55% RH; in servers, inlet 18–27 °C according to ASHRAE. Monitoring and alerts: sensors in aisles/racks, software tools and alerts. One of the primary considerations for energy efficiency in air-cooled data centre cooling is hot aisle/ cold aisle containment. New data centre builds, on the other hand, tend to take. Hot and cold aisle racks are the configurations used in data centers to optimize airflow and temperature control. Here's a brief overview of how this arrangement works: Cold Aisle: In the cold aisle, the fronts of all server racks face each other.