DOE2

DOE2, commonly written DOE-2, is a building energy simulation program developed by the U.S. Department of Energy for estimating annual energy use and costs of buildings on an hourly basis. It is used for design optimization, energy performance assessment, and code compliance studies across commercial and residential sectors.

The program originated in the 1970s as part of federal energy efficiency research. It has undergone several revisions, with widely used variants such as DOE-2.1E and DOE-2.2, and was maintained and expanded by Lawrence Berkeley National Laboratory and the broader research community. The tool has influenced the development of later energy modeling software and remains a reference in the field.

DOE-2 uses a detailed hour-by-hour simulation that models building envelope heat transfer, solar gains, internal heat sources (occupants, lighting, equipment), and central and packaged HVAC systems. It supports a variety of glazing types, shading devices, and ventilation options, and relies on climate data files (such as typical meteorological year) to drive the simulations. Outputs include both annual energy use and costs, as well as hourly or monthly data for end-uses and peak demands.

Users define zones with geometry, envelope properties, schedules, equipment and lighting loads, and HVAC system types. The program then provides results such as total energy consumption, energy costs, and end-use breakdowns, enabling comparisons across design options and operating strategies.

DOE-2 has been influential in building energy analysis, serving as a standard tool for energy code compliance and design evaluation for decades. While newer tools with graphical interfaces have become common, DOE-2 remains in use because of its detailed models and enduring legacy data. The software was released by the Department of Energy and later distributed through research laboratories, with various ports and third-party front-ends to run on modern systems.