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User-friendly modelling environment where you can work (and play) with building models. It provides a range of environmental performance data such as: energy consumption, internal comfort data and HVAC component sizes. Output is based on detailed sub-hourly simulation time steps using the EnergyPlus simulation engine. DesignBuilder can be used for simulations of many common HVAC types, naturally ventilated buildings, buildings with daylighting control, double facades, advanced solar shading strategies etc. Screen Shots


Building energy simulation, visualisation, CO2 emissions, solar shading, natural ventilation, daylighting, comfort studies, CFD, HVAC simulation, pre-design, early-stage design, building energy code compliance checking, OpenGL EnergyPlus interface, building stock modelling, hourly weather data, heating and cooling equipment sizing


The EnergyPlus engine used within DesignBuilder has been tested against the IEA BESTest building load and HVAC tests. Results are available under Testing and Validation on the EnergyPlus web site. DesignBuilder-specific BESTest validation results will be available in June 2006.

Expertise Required

DesignBuilder has been specifically developed for ease of use and while basic understanding of building engineering is useful, DesignBuilder requires minimal expertise. The software is provided with free tutorials and training can be provided if necessary.


200+ (April 2006). The DesignBuilder user base is distributed around the world and growing fast.


Consulting engineers, architects, academic research and teaching departments. DesignBuilder is a very useful teaching tool. Its easy-to-use front-end allows students to focus on learning building energy simulation with minimal time wasted learning software.


OpenGL solid modeller, allows building models to be assembled simply by positioning, stretching and cutting 'blocks' in 3-D space. Realistic 3-D elements provide visual feedback of actual element thickness and room areas and volumes. There are no limitations on surface shape - surfaces having more than 4 vertices are triangulated (where necessary) to ensure compatibility with the EnergyPlus simulator. Building geometry can be imported from CAD data.

Data templates allow you to load common building constructions, activities, HVAC & lighting systems into your design by selecting from drop-down lists. You can also add your own templates if you often work on similar types of buildings. This, combined with data inheritance, allows global changes to be made at building, block or zone level. You can also control the level of detail in each building model allowing the tool to be used effectively at any stage of the design process.

Glazing and other openings in the fabric can either be defined parametrically by making simple model data settings or they can be drawn explicitly.


A comprehensive range of simulation data can be shown in annual, monthly, daily, hourly or sub-hourly intervals:

  • Energy consumption broken down by fuel and end-use.
  • Internal air, mean radiant and operative temperatures and humidity
  • Comfort output including temperature distribution curves, ASHRAE 55 comfort criteria, Fanger PMV, Pierce PMV ET, Pierce PMV SET, Pierce Discomfort Index (DISC), Pierce Thermal Sens. Index (TSENS), Kansas Uni TSV.
  • Site weather data
  • Heat transmission through building fabric including walls, roofs, infiltration, ventilation etc.
  • Heating and cooling loads.
  • CO2 generation.
  • Heating and cooling plant sizes can be calculated using design weather data.

Data can be displayed graphically or in tabular form and can be exported in a range of formats to spreadsheet and custom reports.

Computer Platform

Microsoft Windows XP and 2000

Programming Language

C++ (geometric engine), Visual Basic (dialogs) and Fortran (EnergyPlus simulation engine).


DesignBuilder is an excellent choice for early-stage modelling of building designs. The advanced OpenGL modeller provides an environment in which you can test out various design options for environmental comfort, energy consumption and visual appearance.

The DesignBuilder approach to natural ventilation allows detailed models of natural ventilation air flows with the minimum of effort.

DesignBuilder can be used with custom versions of EnergyPlus which allows researchers to combine GUI ease-of-use with �under the hood� modifications to the EnergyPlus source code.


A range of common HVAC systems is available from within the DesignBuilder user interface but users requiring a wider range of different HVAC types should consider exporting EnergyPlus IDF input files and working in the EnergyPlus IDF editor. An advanced HVAC interface to a wide range of EnergyPlus HVAC systems will be available early 2007.



DesignBuilder Software Ltd


Palace Chambers
41 London Road
Stroud, Gloucestershire
United Kingdom


+44 (1453) 755500


+44 (1453) 750507




Free fully functional evaluations can be downloaded from the website.

Version 1 software costs $1500 for a perpetual license. This includes EnergyPlus and visualisation modules, one-year priority support and all v.1.x software updates. Developed in UK, local support in US, UK, Italy, China.