Operational feasibility of a hybrid roof insulation system with bamboo and vegetation: An experimental study in tropical climatic conditions

Abstract A significant portion of the global energy is consumed for creating thermally comfortable building interiors. Insulating the roof has been identified as an effective measure in addressing the issue. Bamboo-transversed is a novel roof insulation material which has proven to yield significant energy saving. This paper presents the results of an experimental study conducted to compare the Life Cycle Operational Performance of polystyrene insulation, bamboo insulation, rooftop vegetation and hybridizing vegetation with polystyrene and bamboo. Results indicated that Polystyrene is a better thermal insulator than bamboo producing 12% reduction of annual energy consumption in comparison with that of 8% of bamboo. When hybridized with rooftop vegetation, both produce similar energy savings around 13–14%. However, polystyrene produced a reduction of 5% in the 50-year Life Cycle Cost analysis, in which bamboo produced 3% while the vegetated cases producing only 2% saving. Bamboo was proven to be paying back its initial investment in 0.9 years, while the same was 1 year for polystyrene. Hybridized insulated system was proven to take 2–4 years to pay back the initial investment. Hence, it was proven that hybridizing rooftop vegetation with bamboo does not boost the operational performance sufficiently to justify its investment.