ETFE (ethylene tetra fluoro ethylene) is a lightweight material that is increasingly used in building applications. Typical ETFE cushions can provide a degree of thermal insulation with reduced initial cost investments and fewer supports compared with a glazed roof. However, there is limited research regarding the luminous environment inside the ETFE cushion or panel covered structures and limited availability of information on its optical properties, which necessitated the current study. This paper presents a qualitative and quantitative study to assess the lighting performance of an encapsulated ETFE panel structure. Through on-site monitoring and the physical modelling, this research project aims to: understand the existing luminous environment and the current lighting problems identified inside this ETFE structure; develop and test the design alternatives to deal with glare, visual comfort, three-dimensional modelling; and develop workable solutions to improve the normally dull and uniform lighting conditions inside ETFE enclosures. This study concluded that by careful manipulation of the opacity and transparency of the ETFE structure, the luminous environment can be significantly improved or enhanced.