Determining Occupant-Friendly Lighting Environments for the Improvement of Visual Perception

User acceptance studies for LED office lighting: Preference, naturalness and colourfulness

“…The observers feel that objects (including the hand) appeared more natural under a lighting environment at 4000 K than under 6500 K. Also, the free comments given by the observers after each experimental session indicate that they preferred the CCT of 4000 K for office work. This finding supports the work of Shamsul et al, 23 Kang et al 24 and Cockram et al 25 However, Boyce and Cuttle 27 found that 'the CCT of good colour rendering lamps in the range 2700 K to 6300 K has little effect on people's impressions of the lighting of the room.' and Lin et al 21 found that both CCTs of 4000 K and 7000 K at 600 lux were preferred.…”

“…Other important aspects with respect to human perception are CCT and light level. Shamsul et al 23 found that a light source with a CCT of 4000 K was most preferred and most comfortable over CCTs of 3000 K and 6500 K. Kang et al 24 found that observers preferred the lighting environment with a CCT of 4000 K for visual comfort over those with CCTs of 3000 K and 6500 K. Lin et al 21 found 4000 K and 7000 K as preferred CCT settings for LED lighting in an office when the light level was set at 600 lux. Cockram et al 25 found in a field survey, that people preferred a daylight lamp (4300 K) for office work over a FL at 6500 K. Overall, there is some support that people preferred 4000 K lighting environment over 6500 K environment, however, only a few studies 21,22 have been done under LED lighting in an office environment.…”

“…Manav 29 found that 4000 K was preferred to 2700 K for impressions of comfort and spaciousness at light levels of 500 lux, 750 lux and 1000 lux. Shamsul et al, 23 Kang et al, 24 Cockram et al, 25 Boyce and Cuttle 27 and Manav 29 studied FLs, whereas Lin et al 21 and Vie´not et al 28 studied the different CCT environments using LED lighting. The studies mentioned above show inconsistent results and provide little help to understand subjective response to the effects of CCT and light level for LED lighting.…”