​

Daylight is a crucial parameter in sustainable energy research. It reduces the need for artificial light and plays a key role in minimising HVAC costs. Previous research has found that daylight can save up to 77% of the energy used for lighting. However, in overcast locations such as Scotland, designing to ensure sufficient quality and quantity of daylight inside buildings is challenging due to climate conditions, including cloud coverage and sunlight availability (the position of the sun, solar elevation angle and sunlight hours). 

This study aims to assess daylight performance within various façade fenestrations of design studios in three Scottish cities (Glasgow, Edinburgh, and Aberdeen), and its potential to reduce use of artificial lighting. The study's methodology is empirical, with long-term monitoring of illuminance levels conducted inside and outside of the investigated buildings. 

The study found that the most frequent amount of cloud coverage during the study period in the three cities was 8 oktas (overcast, sky completely cloudy). Nevertheless, double-volume studios with high windowsills, no outside obstructions, and window-to-wall ratios of between 44% and 50% registered daylight illuminance levels of more than 500 lux in most daytime measurements taken from February to October, which indicates great potential for saving energy used for lighting. However, the presence of a mezzanine floor in some studios reduced the registered illuminance levels to less than 500 lux.

​

​