When it comes to containment strategies, the most common confusion is usually regarding whether it’s better to contain the hot aisle or the cold aisle. Assuming a computer room is configured in such a way that either is viable, hot aisle containment may be seen as the better option because it has some working environment and ride-through advantages. However, because every computer room is unique, there is no one definitive solution. For this reason, it is important to understand all the differences between hot aisle containment and cold aisle containment so you can make a decision appropriate to a particular architectural environment and business strategy.
For clarification, cold aisle containment involves doors on the ends of the cold aisles and some form of partitions, baffles, or roof over the cold aisle. Hot aisle containment includes doors on the ends of the hot aisle and a configuration of baffles or ductwork from the hot aisle to the returns of the cooling units. Drop ceiling plenums are often used as the means to duct the return air back to the cooling units. Both strategies have their benefits as well as their challenges.