Cleanroom production is energy- and CO2-intensive. It is worthwhile to incorporate energy efficiency into the planning process at an early stage. For the necessary overview, a holistic optimisation approach should be pursued that includes all trades in and around the cleanroom. VDI 2083 Part 4.2 describes important principles for the energy-efficient design and operation of cleanrooms. This presentation takes up selected structural and organisational measures and presents them in a practical and vivid manner. The outlook addresses the topic of subsidies for energy-saving measures.