The potential use of reed as cost-efficient thermal insulation wall claddings for residential energy retrofitting in Egypt

Reed is a tall perennial grass growing along Northern marshlands and Nile bank in Egypt. It is used in building light fences and huts in poor rural areas. This study aims to reexplore reed as a material for low-cost interior cladding to enhance thermal insulation and energy efficiency in residential buildings retrofitting. Thermal conductivities of whole giant reed and crushed common reeds panels samples, within minimal processing, were measured to be used in the design of insulating cladding according to Egyptian Code for Energy Efficiency in Residential Buildings. Then, digital simulation was conducted on a validated non-insulated case-study residential villa, to asses changes in energy performance after retrofitting with reed cladding panels. These results were used to analyze the obtained energy savings and cost to benefit behavior. The lowest thermal conductivity measured for whole giant reeds was 0.081 W/m.K, while crushed common reed acquired a thermal conductivity as low as 0.054 W/m.K. Simulation results indicated that retrofitted models employing giant reeds claddings and common reed claddings achieved better energy savings; 4.73 % and 4.27 %, respectively; compared to model employing expanded polystyrene and gypsum board wall cladding (4.50 %). Additionally, cost benefit analysis showed that crushed common reed-retrofitted model had low cost-benefit ratio, 0.06, indicating a good balance where environmental and economic benefits outweighed initial and lifecycle costs. Giant reeds-retrofitted model ranked second. Both remarkably better than conventional expanded polystyrene and gypsum board-retrofitting. These findings introduce reeds for low-carbon thermal insulation with low initial costs and promising lifecycle environmental and economic benefits.