During the last 15 years, mechanical rooms have seen dramatic changes. The rooms have become smaller with fewer pumps and valves, the equipment has become more effi cient, and more attention is paid to intricacies of connections. The quest is for solutions that are less expensive to build, less expensive to operate and easier to maintain than traditional (or previous) arrangements. This article covers the improvements in chiller plant design, the reasons why each variation was made, the challenges and opportunities that were presented, and the results achieved.