This would depend on the use of the building and being able to strike the best balance of rooflight specification choice for that building. Insufficient rooflight areas can lead to areas of gloom and shadow that requires the use of artificial lighting to overcome poor or inadequate daylight distribution. Using rooflights with high levels of light transmission in only small areas can increase the risk of glare and visual discomfort making the space in the building unusable.
A rooflight area at a minimum of 10 to 12% floor area would often be a little too low with the optimum being around 16 to 18% floor area. If better light distribution is required further, then the rooflight area can be increased, but solar gains would need to be controlled by using solutions with lower levels of light transmission.
