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Update on EnergyPlus Releases
Posted by Michael J. Witte on 23 April 2014 05:16 PM

For the past several years there have been two annual releases of DOE’s energy simulation engine EnergyPlus, in April and October. In 2014, we are skipping the April release. EnergyPlus has recently been translated from FORTRAN to C++ (see announcement at, and additional time was needed to complete the transition which included not only the program itself but also its development environment and processes. The transition is expected to be fully complete in the summer. The next EnergyPlus release will be in the fall of 2014, and we hope to announce a firm date—as well as new features—in the next month or two.

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EnergyPlus 8.1 Updated
Posted by Edwin Lee on 24 January 2014 04:22 PM

EnergyPlus Helpdesk Subscribers:

The EnergyPlus Development Team has released an updated version of EnergyPlus 8.1.  The new build (009) features bug fixes that were addressed in the period following the original October 2013 release of 8.1.  If you are using EP-Launch, the tool should also inform you of the available update shortly.  The download is available at the EnergyPlus home page (

Thank you!

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ASHRAE Design Conditions posted on EnergyPlus helpdesk
Posted by Linda Lawrie on 27 November 2012 03:24 PM

EnergyPlus SizingPeriod:Designday object definitions have been posted on the EnergyPlus helpdesk.

The ASHRAE Handbook of Fundamentals specifies design conditions for 5500+ locations.  These zip files have "macro defined" sets for each in EnergyPlus V7.1 (and later) format. Included in the articles are the "keys" to finding the location in the larger .imf files.

Climatic Design Conditions are discussed in the ASHRAE Handbook of Fundamentals, Chapter 14, 2009 edition.

Annual Design Conditions are (represented by the attachments in EnergyPlus SizingPeriod:Designday form) also discussed in this chapter.

Monthly Design Conditions (represented by the attachments in EnergyPlus SizingPeriod:Designday form) and how they are to be used are also discussed in this chapter. Monthly design conditions for dry bulb temperature (with mean coincident wet bulb temperature) and wet bulb temperature (with mean coincident dry bulb temperature) for .4% and 2% are included.

The links to the postings are:

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Important Weather Converter files missing from install
Posted by Linda Lawrie on 09 June 2012 04:32 PM

Two important files missing from the install for the weather converter program.  Without them, the full set of statistics will not be produced.

Download and instructions:


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Multiple version update programs posted for all platforms.
Posted by Linda Lawrie on 05 June 2012 11:32 PM

Attachments to three knowledgebase articles allow you to download the multiple version programs to convert your older IDFs to current release (or any release in between).

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EnergyPlus Helpdesk Transition Complete
Posted by Michael J. Witte (Import) on 26 April 2012 05:02 PM
The EnergyPlus helpdesk was moved to new servers and new software on April 26, 2012.  If you encounter any problems with the helpdesk, please contact
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