iDbuild is a combined daylight and thermal simulation tool for climate-based daylight and energy performance simulation of rooms in buildings. The program algorithm is simplified yet precise compared to more sophisticated tools available. Furthermore, iDbuild holds a range of unique features not found in any other currently available simulation tools.

The tool is developed by researchers and students at Aarhus University, Dept. of Engineering and Technical University of Denmark, Dept. of Civil Engineering.

For any questions, please contact Associate Professor at Aarhus University, Steffen Petersen at This email address is being protected from spambots. You need JavaScript enabled to view it.

The tool can be downloaded for free right here:

MATLAB version              

STAND ALONE version        



Updated: 30-07-17 Updated: 30-07-17

Regarding the MATLAB version, we cannot guarantee that it works in MATLAB versions which are older that MATLAB 2017a. 

You can also download a weather file converter (.epw to iDbuild format) right here

You may find the .epw file you need right here: EnergyPlus weather data

The algorithms in the program package is well-described and carefully validated. Documentation can be found in the following scientific papers:

Thermal algorithm 
Nielsen T.R. Simple tool to evaluate energy demand and indoor environment in the early stages of building design. Sol. Energy 78 (2005) 73–83

Daylight/lighting algorithm
Hviid C.A., Nielsen T.R. and Svendsen S. Simple tool to evaluate the impact of daylight on building energy consumption. Sol. Energy 82 (2008) 787–798

Petersen S., Momme A.J. and Hviid C.A. A simple tool to evaluate the effect of the urban canyon on daylight level and energy demand in the early stages of building design. Sol. Energy 108 (2014) 61–68

Petersen S. Combined Daylight and Thermal Calculation Tool for Annual Energy Performance Simulation of Rooms with Advanced Daylight-Controlled Lighting Systems. Building Simulation 2017, San Francisco, California, USA

Parameter variation algorithm
Petersen S. and Svendsen S. Method and simulation program for informed decisions in the early stages of building design. Energy and Buildings 42 (7) (2010) 1113-1119

Petersen S. Simulation-based support for integrated design of new low-energy office buildings. PhD thesis, Technical University of Denmark, 2011.

Predictive algorithms
Petersen S. and Svendsen S. Method for simulating predictive control of building systems operation in the early stages of building design. Applied Energy 88 (2011) 4597–4606

Petersen S. and Bundgaard BW. The effect of weather forecast uncertainty on a predictive control concept for building systems operation. Applied Energy 116 (2014) 311–321