Conversely, the cold aisle is where cool air is supplied, creating a controlled environment for servers to operate optimally. Server racks are arranged in rows so that the fronts of the racks face each other, forming a corridor known as the cold aisle. Cold air is delivered into this aisle through: Servers pull this cold air into their front. Assuming a computer room is configured in such a way that either is an option, hot aisle containment may be seen as the better option because it has some thermal efficiency and ride-through advantages. However, because every computer room is unique, there is no one definitive solution. Cold. Hot aisle containment (HAC) and cold aisle containment (CAC) are the most efficient ways of preventing your servers from overheating and these systems are currently being used in data centers all around the world.