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Best Practice

Healthcare lighting

Glare free LED Human Centric Lighting at Slagelse hospital, Denmark

Retrofit requirements

The Danish Slagelse hospital required to maintain certain building features, including the acoustic ceiling and recessed openings of the luminaires, when the retrofitted the lighting system.

The old fluorescent lighting

The previous system consisted of 1640 LFL luminaires. Problems with glare, low illuminance and frequent cleaning were reported.

The new LED lighting

The system was upgraded to closed dust-free LED dimmable luminaires with better lighting spectrum providing Human Centric Lighting by DALI control.


An increase in luminous flux of 28% was produced by the new lighting. The spectrum the LED is much better than the old LFL spectrum (see figure below). The energy savings are 33%. The installation had a payback time of 5 years.


The option remained for further upgrade of the system by adding daylight and PIR sensors. This would be estimated to provide further savings of up to 40%.

Lessons learned

The new LED lighting increased the functionality and quality of light in the hospital at a lower cost, solved issues with glare and maintenance, and improved well-being for patients, visitors and employees. The new LED lighting is considered a best-practice example for other hospitals.

Short description of the technical lighting system

  • Replacement of 1640 LFL luminiares with 1640 LED lumniares
  • 28% higher luminous flux which is appreciated by the hospital
  • 33% energy savings
  • 5,1 years payback time. In case of contant luminous flux, the payback period would be around 4 years
  • DALI (Digital Addressable Lighting Interface) control is used
  • The colour temperature can dynamically be variates between 2700K and 6500K