EFEN 1.3 was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The actual developer of the software is DesignBuilder Software. The most popular version of the software is 1.3.
Commonly, this program's installer has the following filename: EFEN.exe. According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. The program lies within Photo & Graphics Tools, more precisely 3D Design.
From the developer:
DesignBuilder Software is pleased to announce the release of a new, easy to use energy analysis program for evaluating fenestration options in commercial buildings EFEN. EFEN is a next generation energy analysis tool using EnergyPlus simulation engine and intelligent building generator.
You may want to check out more software, such as Plate 'n' Sheet Development Pro., CAD To DMC or TachyCAD, which might be related to EFEN.