Impact of lighting renovation on energy consumption and visual comfort: a case study in social dwellings

The use of energy efficient lighting in dwellings in combination with the preservation, or the improvement of visual comfort is a huge challenge. This paper presents a lighting renovation project in eight social apartments, in Belgium. The lighting system was renovated at four levels of quality, in order to evaluate the light saving potential, the lighting comfort and the influence of the human behaviour on the lighting consumption. The methodology dealt with the criteria and targets of the lighting renovation, the way to record monitoring data and the concept of the extrapolation of consumption. This extrapolation presented a way to obtain more case studies without knowing the occupancy schedule of the occupants. Illuminance, power, luminance, UGR values reached for the different lighting solutions were determined. The measurements showed that if the occupant selected his lighting installation, the comfort is seldom reached. Replacing initial lamps (incandescent) by high efficient compact fl uorescent lamps induced high energy savings and comfort level was reached more often. The visual comfort (higher illuminance level) could even be improved by the use of efficient luminaires. Finally, the paper concludes that, the human behaviour has a large influence on the lighting installation and consumption. Moreover, occupants tended to install the worst lighting equipment (high power level, low visual comfort). However efficient luminaries are not widespread on the domestic lighting market. On the other hand, the extrapolation allowed concluding that for some behaviour profiles there were no economic gains from the use of economic lamps and efficientluminaires. With this study, we point to the importance of evaluating correctly the needs of the occupants in terms of visual comfort and to install adequate energy saving lamps and luminaires.