The invention combines systems and methods for heat containment and cold air isolation for managing airflow and temperature in data centers. The data center contains at least two rows of cabinets containing heat-generating equipment and arranged to form a cold aisle and a hot aisle. The data center system includes panels or doors at both ends of the cold aisle and an optional cover over the cold aisle to inhibit cooled air supplied by an air conditioning system from exiting the cold aisle and inhibit air warmed by the heat-generating components from entering the cold aisle. A chimney coupled to the top, rear, or top and rear of the cabinets is configured to exhaust the warmed air into a region above the rows of cabinets. The chimneys may be ducted to a plenum or suspended ceiling or to the intake of the air conditioning system. Baffles and/or fans may be included in the chimneys, ducts, and/or plenums to control the air pressure. The invention may also include one or more data center air conditioning units, and each air conditioning unit may be configured to service one or more rows of cabinets. Alternatively, or in addition, cool air may be supplied by the building's air conditioning system.