Working outdoors in the sunshine with blue skies and fluffy white clouds overhead – it sounds a little like heaven, doesn’t it? Except when rain falls, snow blows or wind gusts, of course. Skylights can provide much the same effect – for the top floor of a building – on a sunny day. But a new “virtual sky” ceiling lighting setup gives office workers the feeling of being outside, even on the first floor and even when the weather outside is frightful. The idea is to boost productivity and well-being. Light from an artificial sky, such as that produced by these ceiling panels, could promote increased productivity in office settings. The setup, developed by Fraunhofer Institute for Industrial Engineering IAO in Stuttgart in collaboration with LEiDs GmbH & Co. KG of Backnang, both in Germany, simulates sunlight along with passing clouds. To do this, the researchers studied the natural light spectrum and the speed at which it changes as breezes play with clouds. The celestial ceiling consists of 50 x 50-cm tiles, with each one comprising a board with 288 LEDs, said Matthias Bues, head of the Visual Technologies Competence Team at Fraunhofer IAO. A matte-white diffuser film beneath the LEDs produces the effect of uniform lighting throughout the room. Red, blue-green and white LEDs enable the full light spectrum to shine forth. The LEDs enable simulation of the dynamic changes in natural lighting without making the artificiality obvious to the naked eye, Bues said. In a pilot study, the virtual sky was well received. For four days, 10 participants worked under a 30 x 60-cm lighting surface. The lighting was motionless on the first day, fluctuated moderately on the second day and changed rapidly on the third. A total of 80 percent of the volunteers chose the fast, dynamic lighting option when given their choice of illumination for the fourth day. A behind-the-scenes view of the LED panels beneath a diffuser screen, which helps to create uniform lighting for a skylike office ceiling. The prototype “sky” contains 34,560 LEDs spanning an area of 34 sq m. The ceiling can light up with an intensity of more than 3000 lux, but 500 to 1000 lux creates a comfortable level of illumination, the researchers say. There has been some interest in the luminous ceiling for conference rooms. Bringing the outdoors in currently has a high price tag – about $1300 per square meter – but the cost could come down if demand and production increase.