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DesignBuilder Daylighting

DesignBuilder provides 3 types of daylighting calculations:

  1. Daylight contour plots and average daylight factor and uniformity outputs for each zone calculated using the Radiance daylighting simulation engine. Standard reports detailing eligibility for LEED EQ8.1, BREEAM HW1 and Green Star IEQ4 daylighting credits are provided.
  2. Reduced electric lighting and consequent energy and carbon savings due to daylighting through EnergyPlus simulations.
  3. Photo-realistic rendered images generated using Radiance.



Contour plot showing daylight availability across a floorplan
Daylight distribution within a zone       

Daylight Contour Plots and Daylight Factor Calculations

The daylighting simulations available in DesignBuilder v3 allow you to calculate daylight factors and illuminance data using the Radiance daylight simulation engine. The main DesignBuilder daylighting features are: 

  • High quality illuminance contour plots can be generated to illustrate daylight availability within each zone, each block or for a slice through the whole building. 
  • Standard reports are provided detailing eligibility for LEED EQ8.1, BREEAM HW1 and Green Star IEQ4 daylighting credits (an example LEED NC2.2 report is shown below). 
  • Summary tabular output of average daylight factors and uniformity data can be output.
  • Full multi-zone simulation covering tranmission of light through exterior and interior windows. 
  • Internal and external shading obstructions and daylighting features such as light shelves can easily be included in the model using component blocks or assemblies at building or block level. Window frames and dividers are also taken into account if they are included in the model.
  • Calculations are made using the accurate physics-based Radiance simulation engine which is one of the most widely respected daylighting tools in use today. Radiance generates much more accurate results than the "Split flux" method built into some competing daylighting software.
  • DesignBuilder daylighting is fully integrated with the thermal simulation model, so in most cases 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 model includes the thickness of floors and walls, unlike other competing daylight simulation products which only use 2-D surfaces. Using 2-D surfaces has been noted by experts as a significant cause of errors in daylighting calculations.
  • Calculations can be made for various sky types including the CIE overcast sky required for most daylight factor calculations.    
  • Any zone size or shape can be handled reliably.   
  • You can include a margin around the edge of each zone to follow CIBSE guidance.
  • The grid of calculation points can be edited through a maximum and minimum grid size allowing full coverage of zones having complex shape.
  • Default calculation options provide reliable and accurate results but advanced users can access more detailed Radiance parameters to gain full control of the daylighting simulation process.
Example LEED NC2.2 report


Availability: DesignBuilder v2 license holders can test the v3 Radiance daylighting through the beta test software.

Daylighting Integrated within EnergyPlus Energy Simulations

energyplus_logoEnergyPlus allows you to calculate energy and carbon savings through control of electric lights according to the availability of natural daylight. The daylight illuminance level in a zone depends on many factors, including sky condition, sun position, photocell sensor positions, location, size, and glass transmittance of windows, window shades and reflectance of interior surfaces. Reduction of electric lighting depends on daylight illuminance level, illuminance set point, fraction of zone controlled and type of lighting control.

See EnergyPlus daylighting help topic for more information.

Availability: integrated daylighting and energy simulations have been available in DesignBuilder EnergyPlus since v1.

Photo-realistic Visualisations

DesignBuilder can export the Radiance input files required to generate accurate rendered images such as that shown below.   


     Availability: Photo-realistic rendered outputs currently require an export to Radiance.  





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DesignBuilder v4.7 is released!

Free Webinar 28 Apr - DesignBuilder: rapid early-stage analysis through to detailed performance modelling

DesignBuilder SBEM v4.7 approved for England and Scotland EPCs and Part-L2 / Section 6 2015

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