News From Eight

Education sector case study: the positive impact of using skylights in the classroom  

04/11/2015

In the education sector, studies have shown that daylight quality and levels have a positive effect on students’ performance. So, as skylights increase the amount and improve the quality of daylight that a space receives, the question arises, could students’ performance be enhanced through the integration of skylights in schools?

The study below was conducted in Denmark – the findings are transferable to the UK, to any classroom or workspace. Please get in touch if you wold like more details of the study or have any questions about our daylight and sunlight analysis, or daylight impact assessment services, on tel 020 3179 0420 or email info@eightassociates.co.uk.

 

Previous studies have indicated that skylights can improve the daylight conditions in houses or office buildings, decrease the electricity demand for lighting, provide natural ventilation and reduce the heating demand through passive solar heat gain exploitation.

One of our daylighting experts conducted an investigation into the effect of skylights on the energy use, daylight conditions and thermal comfort in a classroom, performing dynamic energy and daylight simulations with Grasshopper, DIVA for Rhino and Archsim (EnergyPlus). A range of variables were accounted for; roof tilt, window-to-floor ratio, skylight-to-floor ratio, skylight distribution, amount and position of skylights, and orientation. Daylight factor, daylight factor uniformity ratio, daylight autonomy, daylight availability and daylight glare probability, heating demand, electricity demand for lighting and overheating time were all investigated.

The study found a successful integration depends on many factors including the building’s location, construction, its use, and the design and placement of the skylights. Skylights affect the energy performance of a building in a complex way:  The use of skylights increase the heat losses while also increasing the solar gains. The heat gains can reduce the heating demand of a space, due to passive solar heating, but can also create thermal comfort problems like overheating. These issues can be balanced through the careful consideration of skylights’ sizing, orientation and protection to prevent glare. Equally, the openings can be used to enhance the effect of natural ventilation and possibly prevent overheating issues. The glazing area at the roof can also improve the overall daylight conditions and increase the daylight autonomy, thus decreasing the need for electrical lighting.

The ‘headline’ finding of the study is the daylight conditions of a space can be improved more easily with the addition of skylights rather than by the increase of window area. The integration of skylights improves daylight conditions of deep spaces and it is recommended for spaces where visual performance is important, such as in classrooms.

Skylights were found to significantly improve the daylight conditions in a classroom, in terms of daylight levels and uniformity as well as daylight autonomy. Visual discomfort problems can be easily avoided through the use of proper shading devices.

The study also showed that the electricity demand for lighting can be significantly reduced: Skylight integration in combination with daylight-linked photo-electric lighting control can reduce electricity demand for lighting by up to 5 kWh/m2 annually.

In terms of where should skylights be located, it was found that placing them further away from the windows increases light uniformity and daylight depth penetration. For both daylight and energy use, the use of fewer and larger skylights is preferable to more and smaller ones, as long as they are well distributed throughout the space.