Version 25.2.0
30 September 2025 EnergyPlus is a trademark of the US Department of Energy.
EnergyPlus is a simulation program designed for modeling buildings with all their associated heating,
cooling, lighting, ventilating, and other energy flows. EnergyPlus is a stand-alone simulation engine
without a 'user-friendly' graphical interface. EnergyPlus reads input and writes output as text files,
although as of 9.3, EnergyPlus became a library.
Utilities and tools for creating, editing, and running input files that come with EnergyPlus include IDF Editor
and EP-Launch. Many graphical user interfaces for EnergyPlus are available or under development. For the latest
tools, please see
this website for third party interfaces. A completely new cross-platform version of EP-Launch has been developed and is available separate from the
EnergyPlus install; see the
documentation
for more information. Some tools may produce out of date IDF files; you can then use the IDFVersionUpdater
program to convert older files to current EnergyPlus version (you may need to use the Multiple Version
Conversions set – see below).
* Python Ecosystem *
The EnergyPlus-Python connections continue to grow. The Python-focused deployment via PyPi is still coming, but
will remain on the
test server on PyPi for now. The
pip install energyplus
experience will bring EnergyPlus native libraries plus the Python API bindings, ready to be used by the user's
desired Python environment. This should make setting up EnergyPlus much easier for many Python-facing use cases!
In addition to the Pip Install work coming along, we are also working to improve our Python integration for
traditional EnergyPlus use cases. When a user downloads the installer package onto their machine, they will get
the new cross-platform Python-based EP-Launch and Version Updater utilities. The classic tools are still
packaged for now, but will likely be deprecated in favor of the Python tools soon. There are a couple ways to
launch the tools, that slightly differ between platforms.
For Windows, there are shortcut files right inside the EnergyPlus install folder called
EPLaunch_Python and VersionUpdater_Python that will launch the tools:
For Windows, there are also start menu items added for both new tools. Note that the classic
tools still exist in the start menu as well:
For Mac, there are now new .app bundles right in the EnergyPlus Applications install folder
that can be launched to execute both of the new EP Launch and Version Updater tools. Once launched these tools
can also be pinned to the Dock for easy access.
For Ubuntu, there are shortcuts in the installation folder called EPLaunch and
VersionUpdater. These are executable shell scripts that launch the Python-based tools with a very native feel.
In addition, as of 25.1, EnergyPlus will install a .desktop folder onto the user's system which enables
integration with the desktop environment. Once installed, launch the applications view (press the Windows
key), and start searching for "EnergyPlus". A new shortcut should be available. By clicking on this shortcut,
EP Launch will be launched. You can also drag this shortcut to the dock. Once in the dock, you can right click
to access either EPLaunch or the VersionUpdater tool:
We are excited for users to give these tools a try and let us know how it goes. As always, we appreciate issue
reports on our
GitHub repository. We will be addressing any issues
identified from user feedback, and at some point deprecating some of these classic tools. We are also planning
to add more tools to this integration, such as a new EpJSON editor.
For a majority of users, EnergyPlus is still basically the same tool, but with some great new features,
bug fixes, and runtime performance improvements. Running EnergyPlus can still be accomplished the same
way, by creating an input file in IDF or EpJSON syntax, running the EnergyPlus(.exe) binary, and
gathering results of interest. All this power is still available. 👍
As of EnergyPlus 9.3, EnergyPlus started becoming a bit more flexible thanks to the addition of a formal
C API with Python Bindings, as well as the ability to execute user-defined Python "plugins" in lieu of
writing user-defined Erl code. In the library mode, a client can make function calls to set up and
execute a simulation, as well as interact with simulation results during a simulation. 👍
👍 👍
A key effort completed with 9.5 was making EnergyPlus "thread-safe" by removing all global and static
data from the program. Now each running thread of EnergyPlus has a complete simulation state, and no
data is shared, so multiple runs can happen within a single process, opening the door for interesting
new workflows and applications.
See the full
ChangeLog
for a complete list of new features added in this and previous versions.
There are a few key changes in the V25.2 IDD. For best results,
use the transition program to transfer from the earlier V.
files. Use the IDFVersionUpdater program for best results.
There have been changes in the following objects which require conversion. Either read and follow the
"Rules" document or use the IDFVersionUpdater utility. The "INSTALL
DIRECTORY\PreProcess\IDFVersionUpdater\Rules25-1-0-to-25-2-0.md" document contains information on exact
object changes that you can do by hand. The updater program is described more fully in the Auxiliary
Programs document.
For output variable changes, check the output rules file and the "INSTALL
DIRECTORY\PreProcess\IDFVersionUpdater\Report Variables 25-1-0-to-25-2-0.csv" document for details, or
just let the transition program run to automatically update them in your input file.
With every EnergyPlus release, there are new checks on user input. Even if your file ran in an earlier
version, it may not run in the newer version after conversion due to newer checks on the validity of
input.
Multiple Version Conversions
The installer includes the IDFVersionUpdater program (see Python section above!) and the necessary programs to
convert from the previous version (including .rvi and .mvi files) to the current version. The installer also
includes the necessary programs to convert from older versions back to v9.0.0. For versions older than that,
first we applaud your dedication to EnergyPlus that stretches for quite some time, and second you will need to
visit the
Helpdesk
to download multiple conversion set of programs.
Documentation
The EnergyPlus documentation is included in pdf form in the installer. The pdfs are also available
online. As of 25.1.0, we began moving a few of our PDFs over
to ReadTheDocs. This includes the Essentials guide
for new users, the auxiliary programs reference, the EMS application guide, and our notices and acknowledgments
listing. Big Ladder Software is also hosting html versions of the EnergyPlus Documentation
online.
There are some other documents of interest available on the EnergyPlus website including:
In addition, we are working to make our API documentation dynamic and hosted on ReadTheDocs. The
README
on our GitHub Repo will be kept up to date with links to our documentation sources as we get things settled
there.
Weather Data
A small subset of weather files that are available on the website are also installed in the WeatherData folder.
EnergyPlus uses these files directly for annual simulations. The Weather Converter program that is part of
EnergyPlus can read these weather files and provide .csv (comma separated variable) as well as statistics
reports about the included (or other) files. Weather data for more than 3000 locations in more than 100
countries can be downloaded on the
EnergyPlus Weather Page.
The full changelog is no longer packaged with EnergyPlus, but can be found on the
release page.
Platforms
We test and develop on Windows 11, and currently produce 64 bit builds on Windows. For Linux, we provide
packages for Ubuntu 22.04 and 24.04. On Mac, we are releasing an installer for OSX on both Intel and ARM
architectures.
Windows 11
Linux (Ubuntu 22.04 and 24.04) 64 bit versions
Mac OSX 12 x64 and 13 arm64
EnergyPlus V25.2 has been tested on all of these platforms
EnergyPlus does intensive computations, and based on configuration, can write massive amounts of data to
disk. For best performance, computers should have a substantial amount of memory and high speed hard
drives.
Installation contents
The installation creates a program folder with icons/shortcuts for the programs/files in EnergyPlus that can be
accessed from Windows menus, including removing EnergyPlus from your system. In Windows OS, these will be
available from the “Programs” area in the Start Menu. Note that only a few of the programs will store anything
in your Windows\System directory (IDFEditor, EPLaunch, WeatherConverter).
Known problems
While every effort has been made to clean up all the “defects” that have occurred during our testing, quite a
few known (and even more unknown) probably remain. Specifics on the remaining known problems can be found on the
GitHub repository
issues page. If you are interested in what has been
addressed, the issues resolved in this release are listed in the
release details.
Additional steps you may want to consider:
Download additional
Weather Data for use in running example files or your files.
The UnmetHours forum allows users to search for answers, ask
new questions about their building simulation models to other users, and generally get quick feedback.
Members of the EnergyPlus development team are also on the forum answering when possible.
The EnergyPlus helpdesk (energyplushelp.freshdesk.com)
requires a login via self-registration or via sending a problem/question to the email address
EnergyPlus-Support@gard.com. In addition to having support
tickets and responses from helpdesk personnel, there are knowledgebase articles.
BLDG-SIM: A free e-mail list for all building energy simulation program users to ask general building
simulation questions to other users and to post announcements (for events, training, job postings, etc.).
See
lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org
for information on joining this email list.
Open-Source License (or distribution license): Licenses for the source code and distribution are available
from the website:
Licensing Info
Thanks for downloading EnergyPlus. Special thanks to our early testers for this release. If you did not
download the previous version, we welcome you. If you are a returning customer, we hope you find the
latest release exceeding your expectations. We look forward to serving you!
EnergyPlus
