The purpose of studying ambient light with LED and T5
Exactly as before, the purpose of the study was to investigate the visual, biological and emotional aspects of light. Research subjects worked in a room without daylight with two different levels of ambient light – 100 cd/m2 and 300 cd/m2, from LED and T5 fluorescent lamps.
Both light sources had the same colour temperature, but different spectral effect distribution. The luminance on the work desk was kept constant at 500 lux for the entire test, just like before. The participants’ experience and state of being was checked using both interviews and cortisol measurements.
LED was experienced as lighter with the same effect as T5
This result confirmed our previous studies: more ambient light stimulates cortisol production and makes participants more alert. But what aroused our interest was that the research subjects thought that the LED lighting seemed brighter than the T5 lighting. This led to the idea that by using LED we would be able to create better light environments which stimulate alertness and well-being and help us to perform better. Since LED lighting was experienced as brighter but with the same power outputs, this also opened the door for greater energy savings.