The Daylighting module provides Spacial Daylight Autonomy, Annual Sunlight Hours, Useful Daylight Illuminance, Daylight Illuminance, Daylight Factor and Uniformity results for each zone using the state of the art Radiance daylight simulation engine.

Daylighting key features

  • Calculate daylight credits for LEED, BREEAM, WELL and Green Star certification schemes.
  • Generate high-quality contour plots to illustrate daylight availability and glare within each zone, block or slice through the whole building.
  • Summary daylight performance data can be shown in tabular reports.
  • Accurate multi-zone daylight simulation, including light transmission through exterior and interior windows and reflection from all surfaces.

Technical specifications

  • Reports on eligibility for LEED v4 and v4.1 BD+C (Options 1 and 2), BREEAM HEA 01 and Green Star IEQ4 daylighting credits.
  • Annual daylighting metrics Spacial Daylight Autonomy (sDA), Annual Sunlight Hours (ASE), Useful Daylight Illuminance (UDI) are all calculated by the Radiance engine.
  • Daylight Illuminance, Daylight Factor and Uniformity results and related reports are also calculated by the Radiance engine.
  • Internal and external shading obstructions and daylighting features such as light shelves and window frames can easily be included in the model using component blocks or assemblies at building or block level.
  • All calculations are based on the accurate physics-based Radiance simulation engine, which is one of the most widely respected daylighting tools in use today.
  • The Daylighting module is fully integrated with the core DesignBuilder thermal simulation feature, so no extra data needs to be added following previous energy simulation or certification project work. In particular, building geometry, zone layouts, surface reflection and glazing visible transmission properties from the thermal model are used in the daylighting calculations.
  • The DesignBuilder 3-D Modeller includes the thickness of floors and walls, reveals, window frames etc, so it can generate highly accurate results. Using 2-D surfaces can cause significant errors in daylighting calculations.
  • Calculations can be made for various sky types, including the CIE overcast sky required for most daylight factor calculations.
  • The grid of calculation points can be edited through a maximum and minimum grid size allowing full coverage of zones of complex shape.
  • Default calculation options provide reliable and accurate results. More detailed parameters to gain full control of the daylighting simulation process can be accessed if required.

If you are looking to simulate how reduced electric lighting use can lead to energy and carbon savings, please check out our EnergyPlus Simulation module.


Daylighting is included in Energy Assessor Plus and all Architectural and Engineering packages.

"We decided to go out and measure some natural light levels in buildings that we have access to.... One building was our own office, and the other was a green building we worked on which will be tenanted in 2 weeks so we had a chance to take readings in the same environment for which we simulated. I am happy to say that the DesignBuilder results are very close to what we measured... What impresses me is that if we measure a value of 250 lux at 3m from the facade, DB returns similar values. This means that if we say that 40% of a building's usable area will have lux levels of 250 or above, then the measured results correlate with that. ... It certainly makes us confident in the results we give to clients."
Warren Gray, Mechanical Engineer
Solid Green Consulting, ZA

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