Lux levels determine whether a space feels functional, comfortable, or oppressive. Too little light and occupants strain their eyes. Too much and the environment becomes harsh, energy bills climb, and glare complaints multiply. Getting the balance right starts with understanding the standards.
What is Lux?
Lux measures the amount of light falling on a surface. One lux equals one lumen per square metre. It tells you how much useful light reaches the working plane, not how bright the source appears. A 5000-lumen fitting mounted at 3 metres delivers fewer lux to the desk than the same fitting at 2.4 metres. Height, beam angle, and reflectance all affect the result.
UK Standards: CIBSE and EN 12464-1
In the UK, CIBSE (Chartered Institution of Building Services Engineers) publishes recommended illuminance levels in the SLL Code for Lighting. The European standard EN 12464-1 covers indoor workplace lighting. Both documents agree on most values. Where they differ, always follow the project specification or the stricter of the two.
Office and Commercial Spaces
General offices require 300 to 500 lux at desk height. The task determines the target. Data entry and detailed paperwork demand 500 lux. Collaborative spaces and meeting rooms work well at 300 lux with supplementary task lighting available. Circulation areas and corridors need 100 lux minimum. Server rooms and storage areas require 200 lux for safe navigation and reading labels.
Retail Environments
Retail demands higher illuminance to attract attention and render merchandise accurately. General retail floors need 300 lux minimum. Feature displays and mannequins benefit from 750 to 1000 lux with tight beam accents. Fitting rooms should provide 300 lux with high CRI sources above 90 to give customers confidence in colour choices. Checkout areas need 500 lux for transaction accuracy.
Hospitality and Hotels
Hotels balance atmosphere with functionality. Lobbies and reception desks need 300 lux at the working surface. Guest room general lighting works at 100 to 150 lux. Reading lights at the bedside should deliver 300 lux on the page. Restaurant dining areas typically operate between 50 and 150 lux depending on the concept. Back-of-house kitchens require 500 lux on food preparation surfaces.
Healthcare Facilities
Healthcare carries the strictest requirements. General wards need 100 lux with the ability to boost to 300 lux for examinations. Examination rooms require 500 lux minimum. Operating theatres demand 1000 lux general with 10,000 to 100,000 lux on the surgical field from specialist luminaires. Corridors in 24-hour areas need 100 lux with dimming for night mode at 50 lux.
Residential Applications
Residential lighting has no legal requirement for minimum lux levels, but good practice delivers comfort. Living rooms work at 150 to 300 lux with layered dimming. Kitchens need 300 to 500 lux on worktops. Bathrooms require 150 lux general with 400 lux at the mirror for grooming. Bedrooms function at 100 to 150 lux general with reading lights at 300 lux.
Exterior and Landscape
External lighting focuses on safety and wayfinding. Car parks need 20 to 50 lux at ground level depending on security requirements. Pedestrian pathways require 5 to 20 lux. Building facades use illuminance for dramatic effect, typically 30 to 150 lux depending on surface reflectance and viewing distance. Emergency escape routes need 1 lux minimum on the centre line.
How to Achieve the Right Level
Achieving target lux levels requires photometric calculation, not guesswork. Factors include room dimensions, surface reflectances (ceiling, walls, floor), mounting height, luminaire spacing, beam angle distribution, and maintenance factor. Professional lighting design software uses IES photometric files from manufacturers to calculate point-by-point illuminance grids. EMPRICS provides IES data for every product in our catalogue.
Common Mistakes
Over-lighting wastes energy and creates glare. Under-lighting causes eye strain and safety hazards. Ignoring uniformity ratios creates patchy environments where some areas feel dramatically different from others. EN 12464-1 specifies uniformity ratios (minimum to average) for each space type. Always check uniformity alongside average lux.
Need help specifying the right illuminance for your project? Our technical team provides free photometric calculations for projects using EMPRICS products. Contact us at technical@emprics.com with your floor plans.