Glare and contact with the exterior
'Glare is usually caused by direct sunlight falling on objects in the office or high exterior luminance values within the field of view. Glare can also occur when using a computer display: the luminance of the reflection of the surroundings may be higher than the luminance of the computer screen.
Solar shading significantly reduces the luminance ratios avoiding an important difference of luminance between the computer screen and the surroundings that would create a visual discomfort'.
Extract ES-SO – REHVA Guidebook
The ES-SO and REHVA guidebook on Solar Shading, published in 2010,presents a summary of scientific research showing the influence of the use of daylight on factors related to worker and student productivity:
- By maximizing the use of daylight without glare and providing daylight responsive lighting controls, a median productivity benefit of 3,75% was found by Carnegie Mellon University.
- On average, major health complaints are between 20% and 25% lower for occupants close to an exterior window, compared to those that work in the interior core without access to view and daylight.
- Access to windows and daylight resulted in a 15% reduction of absenteeism.
- Direct sun penetration into classrooms, especially through unshaded east or south facing windows, is associated with negative student performance.
- Students with adequate natural daylight in their classrooms showed 20% faster progress in maths tests and 26% in reading tests during one year.
From the above it may be concluded that natural daylight has a significant and positive influence on occupant health, wellbeing and productivity. However, adaptive control of daylight – that is movable solar shading -- is needed to guarantee the conditions of good visual comfort at all times.
Buildings with well functioning solar protection can cut the investment cost for cooling and ventilation installations, reduce energy use and create the conditions for good thermal and visual comfort.