Tubular Daylighting Devices and People: A comparison of the human responses to Tubular Daylighting Devices and fluorescent lighting

Tubular Daylighting Devices are used to bring daylight into deep-plan spaces, and meet sustainability goals. However, they are expensive, and justification for their use lies in hypothesised benefits they can provide in areas such as well-being and productivity. Yet, there is very little research into the effects of Tubular Daylighting Devices. The broader daylighting literature suggests that benefits to satisfaction, mood, and performance are possible — though research into the benefits of daylight is still not conclusive.  Therefore, a before and after study was carried out in a windowless computer room in the university to compare how the students responded under TDDs versus typical electric lighting. Their cognitive performance, change in mood, average sleepiness, and perceptions of the room and lighting were measured.  TDDs significantly increased ratings of room attractiveness and brightness, and had no more perceived glare than the electric lighting. Ratings of lighting quality were on a par with both typical electric lighting and good modern lighting. They were also just as effective on overcast days as sunny. No effects were found on performance or sleepiness, and mood results were inconclusive.  Overall, it is suggested that TDDs can be considered to be on a par with good modern lighting, and superior to typical existing lighting. Note, however, that it is possible that effects in rooms with windows could differ from those found here. Further research should use longer exposures and larger sample sizes if they wish to find performance effects.