International Journal of BIM and Engineering Science IJBES 2571-1075 10.54216/IJBES https://www.americaspg.com/journals/show/961 2021 2021 Superior Technical School of Architecture at Barcelona (ETSAB), Polytechnic University of Catalonia (UPC), Barcelona, Spain. Habiba Benzarti ep Ghedas In Tunisia, energy saving in construction has become a necessity. Currently, it occupies third place of 27% of the final national consumption. It will be the first in the head with a percentage of 33% in 2030. The decision-making of the climatic parameters at the preliminary design stage by the designer can reduce CO2 production and improve energy conservation. Therefore, the solar design must take advantage of solar radiation in an arid climate. A horizontal glass surface known as passive solar heating in the winter in which contributes to heating the space and reducing artificial lighting. This paper focuses to study skylight design using Revit architecture. The two conceptual mass modes with separated and grouped skylight are investigated. This study is based on based on Energy Use Intensity, Annual Energy Cost, and Life Cycle Energy Cost parameters to assess performance energetic and environmental of skylight system. The found results show that the skylight system improves the energy efficiency and life cycle of the building only if certain parameters of design are considered. 2021 2021 18 25 10.54216/IJBES.040102 https://www.americaspg.com/articleinfo/22/show/961