The amount of light per surface determines the luminance level. One of the parameters that affect comfort in a space is visual details. For example, when trying to read in an office environment, the intensity of light on your desk should be lux defined according to standards in order not to disturb your eyes. While the outdoor level is equivalent to 10000 lux on a clear day, 300-500 lux should be established in the office.
For the qualified design of natural lighting,
- Place knowledge,
- Distribution of reflected light in the internal environment,
- Reflection of light coming from external structures and environment,
- Cloudiness ratio and time frame,
- The analysis is done by using external vision.
Reflection of the glare effect of the materials used on the façade to the interior can create visual discomfort. Visualization of this situation at the design stage will provide the opportunity to eliminate the visual discomforts that the user may experience before settling. The level of luminosity will be calculated by making comparisons of the transmittance of glasses as visible and other wavelengths as light and heat.
Comfort in the neighborhood; It is embodied by the analyzes that it is connected to heat, air movements, sound distribution, air pollution as well as visual changes.
Daylight analysis: illuminance and glare control
Short answer: Daylight analysis simulates the natural illuminance level (lux) in a space and the potential glare from the facade, taking sun-path, sky cloudiness and the surrounding context into account at the design stage.
When is this needed?
- When adequate natural illuminance must be ensured in spaces such as offices or schools
- When the risk of glare in extensively glazed designs needs testing at the design stage
- When comparing the type, depth or placement of a shading device
- When daylight performance needs to be assessed together with energy modelling (lighting load, glazing choice)
Space → typical illuminance level
| Space | Typical illuminance level |
|---|---|
| Clear, unobstructed outdoor daylight | ~10,000 lux |
| Office work area (reading/writing) | 300–500 lux |
These are standards-defined target ranges: if the light intensity on a desk falls below this range, reading/writing comfort suffers; if it sits above it — especially near windows — the risk of glare increases. The purpose of the analysis is to find the facade and shading design that keeps the whole space within this range.
Worked example: shading-device optimisation
For a south-facing open-plan office in Istanbul with a window-to-wall ratio of 0.46, an annual daylight analysis was run assuming occupied hours of 09:00–18:00. Without any shading device, and assessed against a 300–1500 lux target range, the areas near the windows were found to sit above that range and therefore uncomfortable. Two horizontal aluminium-composite shading alternatives were then compared — six 80 cm-wide panels and ten 40 cm-wide panels — but placed perpendicular to the vertical plane (0°) the discomfort near the windows persisted. In a second stage, the panels’ placement angle was optimised in 10° increments from −60° to +60° to find the configuration that met the target illuminance range. Turkish-language case study: Maksimum Gün Işığı Kazanımı için Gölgeleme Elemanlarının Optimizasyonu.
Process and deliverables
| Steps | Deliverables |
|---|---|
| Building the space/facade model → defining the sun-path and sky model → annual/seasonal daylight simulation → comparing shading and glazing scenarios | Illuminance maps, percentage of area meeting the target range, glare assessment, shading/glazing recommendations |
Reference projects
- Anatolia Ceramic Production Facility: Daylight Analysis, alongside pedestrian wind comfort and facade wind loading on the same facility.
- Sabancı Center Akbank: Visual comfort measurement and design support through Indoor Environmental Quality Consultancy.
On both projects, daylight/visual comfort was assessed together with other building-physics analyses (wind comfort, facade loading, thermal comfort) rather than in isolation — a reminder that daylight decisions are rarely made independently of the rest of the design.
Related tool
There is no dedicated free calculator for daylight analysis yet; to pre-check how glazing/shading choices affect heating and cooling loads, see our UCalc (U-value, Turkish-language tool) and the energy modelling service page.
Frequently asked questions
- What exactly does daylight analysis measure?
- It simulates the natural illuminance level (lux) in a space and the potential glare from the facade or interior surfaces, together with sun-path, sky-cloudiness, surrounding-context and glazing-transmittance data.
- How is glare assessed?
- The reflection of the glare effect of facade materials into the interior is visualised at the design stage; illuminance is calculated by comparing the transmittance of glazing to visible and other wavelengths as light and heat.
- At which design stage should it be done?
- While facade and shading decisions can still change — before the window-to-wall ratio, glazing type and shading-device choices are finalised. A comparison made at this stage is far cheaper than a revision made later.
- How does daylight analysis relate to energy modelling?
- Glazing type, shading and orientation decisions affect natural lighting and the heating/cooling load together, which is why daylight analysis is often carried out alongside energy modelling.
- What inputs does daylight analysis need?
- A 3D model of the space, the window-to-wall ratio and glazing properties, occupied hours, geographic location and the shading effect of surrounding buildings are all defined together to build the annual or seasonal simulation.
Related content
- Energy Modeling: Sibling service showing how daylight decisions affect energy consumption.
