A precise answer depends on many factors including the roof orientation, tunnel length, tunnel angles, time of day, season of the year, etc. However, VELUX Sun tunnels are ideal for hallways, walk-in-robes, pantries, toilets and other small areas without natural light. The same size rigid tunnel will always transmit more light than a flexible tunnel of the same size, length and configuration.
For other areas, VELUX recommends the use of skylights.