The Hot Air Containment Systems (HACS) is usually recommended if you use the InRow cooling system. InRow cooling itself is an extremely effective solution. By closing the hot aisle, complete separation of the hot and cold air is achieved, and thus complete absorption of all hot air into the InRow cooling units, which further increases the efficiency, capacity (cooling power) and predictability of the cooling system’s operation in the data center.

The Cold Air Containment Systems (CACS) is recommended in case of room cooling solutions (CRAC units) with cold air distribution under the modular raised floor. By closing the cold aisle, the air that is blown vertically out of the raised floor grilles does not escape from the cold aisle, thus fully used by ICT equipment. Part of the downside of closing a cold aisle is that the temperature in the res tof the data center space is quite high (depending on ICT equipment load) and can present a somewhat uneasy feeling when staff enter the data center.