This paper discusses the relationship between forehead illuminance, brightness sensation and luminous comfort with respect to ambient electric lighting systems in living rooms. We asked 20 persons, from 25 to 60 years old, to record and report the lighting appliances they use, while at the same time to measure their exposed illuminance while they were at home in the evening. Their living rooms are mostly illuminated by one lamps on the ceiling and their luminous comfort levels were unrelated to exposed illuminance levels in the living rooms. We also investigated brightness sensation and luminous comfort of these persons in the experiment as the subjects in three experimental living rooms with different types of lighting. The subjects evaluated the experimental living room with direct lighting to be somewhat bright in comparison to the other rooms with indirect lighting. We also found that indirect lighting system with the aid of a task lamp could provide the subjects with sufficient brightness sensation and luminous comfort. These findings suggest that it is possible to design a luminous environment in living rooms with less electric power consumption than present lighting systems.
