DOE2 is a set of programs for the analysis of energy consumption in buildings. Programs are included to calculate the heating and cooling loads for each space (zone) in the building for each hour of a year (LOADS), to simulate the operation and response of the equipment and systems that control temperature and humidity and distribute heating and cooling to the space (SYSTEMS), to model primary energy conversion equipment that uses fuel (e.g. oil, gas, or sun) to provide the required heating, cooling, and electricity (PLANT), and to compute the life-cycle cost for building operation based on economic parameters (ECONOMICS). A user-oriented building description language (BDL) facilitates the description of the building geometry, central plant equipment, HVAC systems, occupancy, equipment, and lighting schedules, and the selection of other problem parameters. In addition to the LSPE programs (LOADS, SYSTEMS, PLANT, and ECONOMICS), the system includes the BDL processor, two report generators, a weather data processor, and UPDATE, a code maintenance program. Standard output reports are produced by the RPTGEN program. Only the weather data for Chicago, which are required for execution of the sample problems, are included.