An introduction to EnergyPlus

EnergyPlus is a program for analysing spaces in buildings for various qualities such as occupant comfort and energy consumption. The program itself seems to have no GUI and interacts using command prompts and text input and output files, but it is intrinsically designed to interact with third party programs in all aspects including input, output and data manipulation. This makes it a great candidate for acting as a core for innovative building design methods. E+ is produced by the US Department of Energy and is free to use.

EnergyPlus website

The fact that EnergyPlus is not an all-in-one packaged solution in the way that IES gives it a steeper learning curve, and thus less desirable for newcomers, or people already used to such programs. However, after speaking with many people, it seems that once you are used to this program, you are well rewarded with a very powerful and flexible tool. This page is an attempt to figure out how to get started with E+ and how to get it doing something useful.

EnergyPlus is not an analysis solution in itself

If we use EnergyPlus as it is for our analysis, the only way to interact with it is to manually type the geometry data as a text file. The results we get are also a text file – a list of numbers. This is obviously not very good.

In reality, we use software to treat EnergyPlus as a core calculation engine, and wrap it with more user-friendly tools that help us to create models we want to analyse, and to make sense of the results.

Common plugins for EnergyPlus

I still haven’t tried any of these – but after some browsing, these are things I’d like to try… Note that this is also a growing list as I find more interesting stuff. More can be found on the E+ site.

OpenStudio seems to be an attempt at an all-in-one solution that handles geometry manipulation, results viewer and parametric design. It also has a link directly into SketchUp for geometry.

Legacy OpenStudio Plugin for SketchUp is the historic equivalent of the SketchUp plugin within OpenStudio.

DesignBuilder, like OpenStudio, attempts to be an all-in-one design environment. It seems to be built at least partly upon EnergyPlus. Not free and not cheap either!

More interesting plugins

GenOpt (Generic Optimization) is a platform-neutral optimisation tool that can interact with any text input/output files, of which EnergyPlus is one.

Ladybug is a GH plugin for EnergyPlus

Competition to EnergyPlus

Related programs which attempt to analyse comfort and energy performance at a building scale include:


Green Building Studio / Ecotect


Misc (tidy up later)

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