EnergyPlus is a building simulation program written in a
modular fashion using the Fortran 90 programming language.
Most programs have progenitors: EnergyPlus is no exception. It
is built upon the DOE-2 and iBLAST building simulation
programs. Both of these programs were written in Fortran 77
without any consistent style or structure. Consequently, both
programs had become difficult to understand, maintain and
extend.
The EnergyPlus Programming Standard is intended to be a
coding guideline for EnergyPlus software developers. The rules
and standards described in this document are intended to
impose a consistent structure and style on all code written
for EnergyPlus. This consistency should aid all present and
future developers in understanding, maintaining, and adding to
EnergyPlus.
All Fortran code will be separated from text and formatted
using the following notation to distinguish it from other
information:
SUBROUTINE ReportZoneConditions ! EnergyPlus Subroutine
INTEGER ZoneNum
DO ZoneNum=1,MaxNumZones
Introduction[LINK]
EnergyPlus is a building simulation program written in a modular fashion using the Fortran 90 programming language. Most programs have progenitors: EnergyPlus is no exception. It is built upon the DOE-2 and iBLAST building simulation programs. Both of these programs were written in Fortran 77 without any consistent style or structure. Consequently, both programs had become difficult to understand, maintain and extend.
The EnergyPlus Programming Standard is intended to be a coding guideline for EnergyPlus software developers. The rules and standards described in this document are intended to impose a consistent structure and style on all code written for EnergyPlus. This consistency should aid all present and future developers in understanding, maintaining, and adding to EnergyPlus.
All Fortran code will be separated from text and formatted using the following notation to distinguish it from other information:
Documentation content copyright © 1996-2026 The Board of Trustees of the University of Illinois and the Regents of the University of California through the Ernest Orlando Lawrence Berkeley National Laboratory. All rights reserved. EnergyPlus is a trademark of the US Department of Energy.
This documentation is made available under the EnergyPlus Open Source License v1.0.