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Internal Daylight Modelling

Daylight has a direct effect on occupant health and wellbeing. It is also an important parameter of the building’s energy performance. Maximising natural daylight through building design can reduce energy consumption. Conversely, too much daylight is associated with overheating, glare and a lack of privacy.

SRE undertakes detailed daylight calculations, both point in time and climate based, to optimise building design, minimise global warming potential (GWP) carbon dioxide equivalent (CO2e) emissions and maximise occupant comfort, health and wellbeing.

SRE also undertakes daylight calculations and produces reports in support of the Building Research Establishment Environmental Assessment methodology (BREEAM), US Green Building Council (USGBC) Leadership in Energy and Environmental Design (LEED) methodology and the International Well Building Institute (IWBI) Well Building Standard (WELL).

Read more about Internal Daylight Modelling

Often local planning authorities require an Internal Daylighting Analysis to be undertaken for proposed new dwellings to illustrate that future occupants will experience high quality, naturally lit spaces. In addition, daylight performance considerably impacts the energy consumption of a building. The creative use of daylight in buildings can significantly reduce artificial lighting energy consumption and therefore, the associated CO2e emissions.

Our building physics specialists carry out daylight modelling by following the recommended internal daylight standards methodologies as detailed in the Building Research Establishment (BRE) guidance ‘Site Layout Planning for Daylight and Sunlight’ (2022), the British Standard of Practise for Daylight (BS EN 17037-2018) and the Chartered Institution of Building Services Engineers (CIBSE) Lighting Guide LG 10 Daylighting and Window Design.

The daylight simulation is based on Radiance software accessed through the graphical user interface (GUI) of either the Ladybug tools 1.60 plugin in Rhino/Grasshopper or Integrated Environmental Solutions (IES) Virtual Environment (VE) 2023 software. Radiance uses the backward ray-tracing method and an enhanced 2-phase method for daylight simulation which accurately models direct sun by tracing rays from each sensor to the solar position at each hour of the calculation, using a climate-based sky.