Third-Party Graphical User Interfaces

Many graphical user interfaces for EnergyPlus are available or under development, including DesignBuilder, EFEN, AECOsim Energy Simulator, Hevacomp Simulator V8i, COMFEN, Solar Shoe Box, N++, gEnergy, Simergy, Beopt™, Sefaira, Archsim, FineGREEN, and EBEST.

Interfaces for older versions of EnergyPlus include CYPE, MC4 SUITE, SMART ENERGY and EPlusInterface.


DesignBuilder (DesignBuilder USA) is a fully featured EnergyPlus user interface suitable for
use at any stage of the design process. First released in 2005, DesignBuilder allows a wide range of building types to be simulated using the latest version of EnergyPlus. Advanced design options
such as natural ventilation, daylight control, double facades, chilled beams, and heated floors can be assessed for their impact on the building environmental performance, comfort, cost, and daylight availability.

Screen shot from DesignBuilder HVAC design.

DesignBuilder is widely used in both commercial design and education sectors. Applications include:

  • Building design analysis from early architectural stages through to HVAC design
  • LEED EA and EQ prerequisite and credit assessment
  • BREEAM credit assessment. DesignBuilder complies with the
    requirements set out in A10 of the BREEAM documentation. It can be used for carbon, comfort and daylighting credits.
  • Calculating Commercial Building Tax Deductions under the IRS tax code Section 179D
  • Detailed design through CFD with links to load EnergyPlus temperatures and airflow as CFD boundary conditions.
  • Assess daylight illuminance effectiveness through Radiance ray tracing simulation.

DesignBuilder also offers a full-featured user interface to EnergyPlus HVAC. Both air and water sides can be treated by placing and connecting components in a graphical environment.
The HVAC interface is integrated with the building model and provides access to most HVAC component types.
All of the ASHRAE 90.1 baseline system types are included.

BIM models created in Revit, ArchiCAD or Microstation can be loaded into DesignBuilder through a gbXML import process.
Revit users can access DesignBuilder while working on their BIM models through a plugin, which allows the model to be checked and analysed without leaving Revit.

Screen shot of an example DesignBuilder 3-D modler.

Alternatively building models can be assembled quickly and easily within the DesignBuilder modeler by drawing and positioning 3-D blocks. Blocks once drawn can be cut, stretched,
merged with other blocks etc then partitioned into zones. Realistic 3-D elements allow correct room areas and volumes to be used in daylighting and CFD simulations and add to realism in rendered views.

A 30 day trial version of DesignBuilder is available.
You can find out more about DesignBuilder on the website or download a brochure.


Screen shot of EFEN interface.
Screen shot of EFEN interface.

EFEN is an energy simulation program designed for analyzing energy impacts and cost effectiveness of fenestration systems in various commercial and high-rise residential buildings. The program incorporates a user-friendly graphical user interface (GUI) and enables quick and effective parametric analysis of different fenestration systems. EFEN utilizes the EnergyPlus simulation engine to perform building energy consumption analysis. The main feature of the program is that it incorporates several pre-defined default commercial building types with typical construction, interior loads, operating schedules, and HVAC system configurations, such that users can quickly develop an energy models of a building.

The EFEN program has an interface to the WINDOW computer tool to assist in the accurate specification of fenestration systems. Users can simply select from the library of WINDOW products, specify dimensions, shading devices, location within the building and orientation schedule. The inner structure of the program is based on number of predefined EnergyPlus files representing various building types and characteristics, which are accessed by EFEN and utilized to simulate the energy consumption of the building.

Annual energy consumption and cost results are produced by the program and organized in intuitive output tables and graphs enabling users to quickly evaluate comparative results (i.e., parametric runs). EFEN also provides options for customizing report generation. In addition to energy and economic analysis of various fenestration options for non-residential buildings, future version of EFEN program will incorporate module for code compliance and other voluntary criteria, like Energy Star, ASHRAE 90.1, etc. The first version of EFEN was released in November 2007.

Main characteristics of the program

  • Simple and intuitive user interface limits the time spent preparing an energy simulation.
  • EnergyPlus simulation engine ensures high-level of accuracy and reliability in comparative energy simulation.
  • Pre-defined default building types and configurations have already been incorporated using well researched building characteristics.
  • Pre-existing database with weather, operating schedules, HVAC system details, and constructions
  • Direct link for fenestration input with industry standard WINDOW program.
  • Intuitive output tables and graphs so that users can effectively evaluate results.
  • Customized versions of program with links to manufacturers' window product database available.

AECOsim Energy Simulator

Screen shot of the AECOsim Energy Simulator.
Screen shot of the AECOsim Energy Simulator.

Bentley Systems released the second version of its new building performance simulation product, AECOsim Energy Simulator, in May 2013. Energy Simulator incorporates the EnergyPlus V7.2 simulation engine for building performance calculations, and also includes steady state design methods such as ASHRAE RTS, ASHRAE heat loss, and CIBSE Heat Gain/Heat Loss. Built on top of Bentley's BIM platform, Energy Simulator allows users to work seamlessly between industry CAD, BIM, and AEC applications such as MicroStation, AutoCAD, Revit, and others and supports standard file formats such as gbXML, DXF, DGN, DWG, PDF, BMP, JPG, and PNG.

Energy Simulator is available now through the Bentley website, as a 30-day trial. You can also read more about Energy Simulator.

Energy Simulator features comprehensive HVAC systems capabilities — exposing all the inputs for EnergyPlus HVAC components and systems, but also provides more than 29 preconfigured HVAC systems that require few user inputs. The HVAC designer also displays the loops and connections for the systems. Energy Simulator automatically creates the baseline and budget buildings for ASHRAE Standard 90.1 (2004, 2007, and 2010) and creates energy performance data for use in AECOsim Compliance Manager for LEED 3.0 documentation. Space type data from ASHRAE Standards 90.1 and 62.1 (2004, 2007, and 2010) are also available.

Check out the EnergySimulator YouTube Channel for video demos of Energy Simulator.

Hevacomp Simulator V8i

Screen shot of Hevacomp Simulator V8i

Hevacomp Simulator V8i is Bentley’s easy-to-use graphical interface for EnergyPlus. Hevacomp Simulator V8i provides designers, building engineers, and consultants with the tools they need to meet the challenges of creating energy-efficient buildings that are tuned to their environment, perform for their occupants, and provide ROI for their owners.

Hevacomp Simulator V8i allows users to set up 3-D by tracing the internal perimeters of rooms and and the perimeters of floors and roofs from 2-D DXF files. Simulator V8i automatically detects adjacent surfaces as partitions and trims walls vertically to fit the roof. Flow paths and window opening can be defined to facilitate analysis of complex natural and mixed mode ventilation systems to be examined, including controlled opening of windows.

Simulator V8i’s detailed profiling and scheduling module allows users to set up plant, gains, occupancy, and temperature schedules. Typical schedules for a range of buildings are provided. A plant module allows engineers define HVAC systems such as radiators, warm air, constant volume A/C, VAV, fan coils, as room A/C units as well as plant equipment such as boilers, chillers and cooling towers. Simulator V8i includes a database of common equipment as well as templates for common system configurations.

Hevacomp V8i contains a large database of ASHRAE, CIBSE, and Meteonorm design day and annual weather files. It supports sizing of HVAC systems as well as annual energy analysis to examine room heat losses and gains, summer overheating, overheating frequency, energy consumption, fuel cost, and carbon emissions.

Simulator V8i is part of Bentley Hevacomp’s suite of tools for building energy analysis, mechanical design and load calculation, and code compliance and documentation for U.K. Part L, Australia Section J, and the U.S. Green Building Council's LEED program. Simulator V8i can use the same project data that was set up for simple load calculations, providing engineers with a low-overhead path to simulation. Find out more about the Hevacomp suite of tools here.


Screen shot of N++ Program

N++ is a building energy modeling interface from ExpertApp based on the latest version of the EnergyPlus whole-building energy simulation engine (V8.0). N++ is built on the principle that building energy modeling should be intuitive, fast, flexible, and most importantly visual, with a CAD-like environment that fits in the conventional design process. N++ allows architects, engineers and energy professionals develop and manage building energy models in a timely fashion, to analyze multiple design scenarios through either desktop or cloud-based simulation, and to inform project decisions.

Currently available for download, the main features of N++ are:

  • Model creation in CAD-like environment
  • 3D orbit view and editing of model geometry
  • Drag and drop of the main Energy Plus objects
  • Import of raster and dxf drawings for fast zone tracing
  • EnergyPlus model import and export
  • Enhanced parametric analysis and optimization through jEPlus (link)
  • Parallel simulation on desktop computer, local network or cloud services (currently via JESS server)
  • Case tagging of the objects that allows multiple model versions in the project (Proposed design, LEED baseline, Code compliance …)
  • Lighting and electric equipment count
  • Graphical representation of the simulation results
  • SVG viewer for model diagrams
  • Enhanced HTML report viewer


Screen shot of gEnergy Program

greenspaceLive’s gEnergy is a cloud-based building information modeling (BIM) platform that leverages the EnergyPlus whole-building energy simulation engine. gEnergy enables architects, engineers and building owners to design and operate energy- and resource- efficient buildings.

gEnergy graphical web interface enables the creation of new EnergyPlus models using over 600 types of building objects, including constructions and HVAC equipment. It also imports existing EnergyPlus models as well as 3D BIM models from SketchUp, Revit, as well as gbXML.

gEnergy is built for project management and collaboration. Its cloud infrastructure makes models accessible from anywhere at any time and facilitates sharing and collaboration with colleagues, consultants, and clients. State-of the-art web collaboration technologies facilitate development of robust models and dissemination of simulation skill and knowhow. It also reduces IT costs with elastic computing capacity, secure project data storage, and transparent software updates.

gEnergy has a large number of training examples and is free for trial use.


Simergy is a free comprehensive graphical user interface for EnergyPlus. Funded by a public-private partnership and designed with input from architects and engineers, Simergy has a full set of features that support rapid model construction along with deep energy analysis. Simergy’s main feature groups include:

Screen shot of Simergy Program

  • Multiple geometry creation and import paths. Simergy supports rapid creation of parameterized geometry using extruded standard floorplate shapes. Fenestration—including horizontal and vertical shading—can also be created quickly using paramerized inputs. Simergy can also import geometry from CAD programs using either IFC or gbXML.
  • Powerful zoning and zone grouping features. With geometry in place, Simergy supports both automatic or manual zoning, as well as grouping of zones with the same internal conditions and—independently—zones with the same HVAC equipment. Editing zones in groups rather than individually saves time and reduces error. Simergy also includes a graphical schedule editor.
  • Graphical HVAC editing and a large number of system templates. Simergy includes a drag-and-drop HVAC editor and comes pre-loaded with templates for a large number of standard systems including all ASHRAE 90.1-2010 baseline systems. As users customize their designs, Simergy can validate the different HVAC configurations without actually running EnergyPlus, saving time and providing insight.
  • A rich library of standard schedules, construction assemblies, HVAC equipment, and weather files. Simulation data sets—thermal properties, efficiencies, capacities, etc.—for building components of all kinds are available in searchable libraries, facilitating the creation of a complete thermal model.
  • Standard reports and flexible result navigation, along with support for multiple design alternatives. In addition to standard reports like zone temperature and unmet load profiles, and monthly electricity and gas end-use breakdowns, Simergy gives the user structured access to all of the EnergyPlus outputs for diagnosis of performance. By supporting multiple side-by-side design alternatives in a single session, Simergy lets users focus on the key performance differences between designs.

Simergy is available for the Windows operating system and currently supports EnergyPlus V7.2. The website links to reference documentation, workflow guides, and short, task-oriented training videos.


Screen shot of BEopt Program

The BEopt™ (Building Energy Optimization) software provides capabilities to evaluate residential building designs and identify cost-optimal efficiency packages at various levels of whole-house energy savings along the path to zero net energy.

BEopt can be used to analyze both new construction and existing home retrofits, through evaluation of single building designs, parametric sweeps, and cost-based optimizations.

BEopt provides detailed simulation-based analysis based on specific house characteristics, such as size, architecture, occupancy, vintage, location, and utility rates. Discrete envelope and equipment options, reflecting realistic construction materials and practices, are evaluated.

BEopt has been developed by the National Renewable Energy Laboratory in support of the U.S. Department of Energy Building America program goal to develop market-ready energy solutions for new and existing homes.


Screen shot of Sefaira comparison

Sefaira allows architects to focus on building performance from the beginning of the design process and to use performance feedback to influence their design, as opposed to evaluating the performance of the final design at the end of the process. Architects can use Sefaira to study form and façade options, find the most effective passive strategies and bundles, and optimize design parameters such as orientation, shading length, and glazing ratios. All analysis is done in the cloud and results are delivered within seconds, making iterative design and parametric calculations possible.

Sefaira can directly analyze SketchUp and Revit files, plugging seamlessly into popular workflows. Architects can begin an analysis by specifying only two additional inputs: space use and location. Other parameters are set to standard values, which can be manually overridden by the user at any time. No specific expertise is required. Sefaira provides training for new users as part of the subscription.

Screen shot of Sefaira grid

    Sefaira analysis includes:
  • Building energy and water use
  • Carbon emissions
  • Utility costs
  • Renewable energy potential
  • Heating and cooling capacity
  • Thermal comfort / overheating

Sefaira leverages two engines for different types of analyses. Sefaira’s proprietary implementation based on ASHRAE’s Radiant Time Series method is used for energy calculations. The second engine is EnergyPlus is used for thermal comfort calculations.

Find out more about Sefaira at


Screen shot of FineGreen interface.
Screen shot of FineGreen interface.

FineGREEN is a BIM simulation environment that combines the Building Information Modeling power and user friendliness of the 3D Building interface, with the reliability and accuracy of the EnergyPlus calculation engine. FineGREEN embeds the latest version of EnergyPlus and allows the easy determination of the best energy-efficient building design solutions from the initial architectural concept through the HVAC design and the entire project completion.

FineGREEN generates the input data for EnergyPlus regarding both, a) the building envelope (geometry parameters of the building elements, building location and orientation, shading model automatically updated by the neighbouring buildings and other outdoor objects), and b) all the necessary complementary data (climate data, systems’ parameters regarding HVAC and lighting, zone parameters such as the density of occupants, operating schedules and behavioural pattern).

FineGREEN’s high efficiency is due to its Smart 3D BIM building model, being composed by intelligent building entities/objects with their own specific properties (i.e. U-Values, types following Ashrae etc). On this 3D BIM model, the user can easily define intelligent building properties (i.e. visual definition of building zones, non-conditioned spaces, shading from adjacent buildings, etc). Its easy-to-use (Autocad®-like) BIM interface is full DWG compatible and at the same time full IFC compatible to ensure the close collaboration with any other BIM application, such as Revit, Archicad, Allplan, IDEA etc. FineGREEN enables the designer to study effectively alternative design scenarios in order to reach the optimal solutions for any type of a new construction, as well as to identify the most interesting retrofit design alternatives.

FineGREEN incorporates Energyplus within a seamlessly integrated BIM environment. It uses energy performance and consumption indicators, precisely calculated for alternative design scenarios and permits the real time extraction of the building annual energy consumption along with costs and other outcomes. Simulation results are organized in detailed output tables, charts and graphical representation forms, to make easy the comparative evaluation of the alternatives.

FineGREEN contains rich libraries open to the user, including building components, construction assemblies and materials, weather files and climate data, HVAC and lighting equipment, as well as ready to use templates with structure and system profiles, operating schedules etc.

FineGREEN collaborates seamlessly with FineMEP and FineHVAC to support the detailed sizing of the HVAC systems, by providing detailed calculations according to the specific standard/norm selected, plus complete drawings with construction details.

You can find out more on FineGREEN at:


Screen shot of Archsim work environment

Archsim Energy Modeling is a plugin that brings fully featured EnergyPlus simulations to Rhino/Grasshopper and thus links the EnergyPlus simulation engine with a powerful parametric design and CAD modeling environment.

Archsim allows you to effortlessly create complex multi-zone energy models, simulate them and visualize results without ever switching between tools. Archsim supports advanced daylighting and shading controls, ventilation modules such as wind and stack natural ventilation, airflow-networks, simple HVAC, photovoltaics, and phase changing materials. It is typically used for rapid early design exploration where building shape, window to wall ratios, facade and glazing systems and passive approaches such as shading and natural ventilation potential are tested for their impact on the building environmental performance and comfort.

Screen shot of Archsim Energy Modeling for Grasshopper

Simulation inputs such as model geometry, materiality, constructions and zone usage profiles are fully parametric and can be coupled with optimization algorithms within Grasshopper.

Archsim is a young tool under heavy development and new features are added frequently. Archsim exports native IDF files that are fully customizable. Besides EnergyPlus version 8-1-0 IDF files, the same workflow can also produce TRNSYS B17 files.

Documentation and example files, community support and most importantly a copy of Archsim are available under