Lighting Studies and Lighting Calculations: What You Can Expect from the Numbers

What a Lighting Calculation Demonstrates

Lighting calculations are particularly valuable during the design phase: they allow you to compare options objectively before placing an order or starting installation. A correctly prepared lighting calculation is particularly effective at quantifying the essentials:

• Illuminance levels, expressed in lux, on work planes or at floor level, in line with the intended function and applicable standards
• Uniformity: how evenly light is distributed throughout a space
• A comparison of luminaire types, optics and mounting distances
• The impact of mounting height and positioning on the lighting effect

The Inputs That Make a Lighting Study Valuable

The better the input, the more realistic the calculations and the more predictable the final result. This is also why a lighting study should ideally be carried out early in the project process: it allows you to adapt the lighting plan accordingly.

A strong lighting study starts with:

• Accurate dimensions and the function of each area, such as workspaces, circulation areas, reception areas, meeting rooms or logistics zones
• Work plane heights, mounting heights and ceiling build-up
• The intended level of visual comfort
• Material and colour selections, used to determine realistic reflectance values
• The desired controls and scenarios, including lighting scenes, dimming and zoning

Where Numbers Can Be Misleading

A lighting study helps guide decisions, provided that the input data is correct.

Typical pitfalls that can lead to misunderstandings include:

• Finishes: Wall colours, floor finishes and ceiling materials all influence how light is reflected within a space. A room with dark walls behaves differently from a room with light-coloured surfaces.
• Layout and furniture: An open-plan office has different lighting requirements from a retail space with wall units, tall shelving or glass partitions. Read more about retail lighting.
• Glare and comfort: Lux levels may be fully compliant while users still experience discomfort due to sightlines, screen work, reflections or an unsuitable optic.
• Maintenance factor and ageing: Light output changes over time as a result of dirt accumulation and ageing. A realistic maintenance and usage context is therefore essential for realistic calculations.
• Last-minute changes: If the ceiling height, luminaire positions or room layout changes after the calculation has been made, the results will no longer match the actual space.

Want to Make Sure Your Lighting Study Reflects Reality?

Are you looking for a lighting study that does more than simply tick the compliance boxes, and also considers comfort, finishes and the wider project context? Multiline supports architects, installers and engineering consultancies with project-specific lighting advice.

Contact our lighting advisers to discuss your project.