Effectiveness Analysis of Insulation and Roof Covering Material in Office Flat Roof

Wasteful consumption of electricity in high-rise building in Indonesia is the primary trigger for the increase in carbon emissions. Predominantly, the excessive use of electrical appliances and air conditioning systems is the principal factor contributing to the use of energy within these structures. To effectively address this issue, the importance lies in adopting suitable building envelope material. Therefore, this study aimed to analyze the effectiveness of different insulation types and roof covering in improving the energy-saving performance of office building. There were six proposed renovation for the flat roof of building, consisting of two approaches, namely (1) the incorporation of insulation and (2) the replacement of roof covering layers. Scenarios A1, A2, and A3 have incorporated 100 mm of polyurethane (PU) foam, polyisocyanurate (PI) foam, and fiberglass batt into the design. Meanwhile, Scenarios B1, B2, and B3 opted for ceramic material, Ethylene Propylene Diene Terpolymer (EPDM) membrane, and grass vegetation as roofing material for the existing roof. The results showed that the addition of insulation to roof through Insight 360 and the replacement of roof covering layers produced an energy reduction of 19.5% to 20.2% and 19.5% and 23.5%, respectively. The implementation of green roof in scenario B3 was selected as the most promising renovation option, achieving a remarkable 23.5% reduction in energy consumption.