The Impact of Green Roofs on Indoor Temperature Reduction Using Native Plants and Substrate Variations in Abu Dhabi, UAE.

Abstract

Urban areas in arid regions, such as Abu Dhabi in the United Arab Emirates, face extreme heat and rising cooling-energy demands. To the best of knowledge, this is the first experimental study in the UAE to directly compare soilless and soil-based green roof systems using specific native, drought-tolerant plant species—Alternanthera amoena, Pennisetum setaceum, Sesuvium portulacastrum, and Ruellia simplex— to evaluate their impact on indoor temperature reduction under real rooftop conditions. Over nine months (December 2023–August 2024), five rooftop models were installed on a residential villa in Abu Dhabi, recording 3,174 temperature measurements during peak daytime and nighttime periods. Models 1 and 2 used soilless substrates with Alternanthera amoena and Pennisetum setaceum, respectively; Models 3 and 4 used soil substrates with Sesuvium portulacastrum and Ruellia simplex; Model 5 was a control without vegetation. Green-roof models consistently reduced indoor temperatures compared to the control. In January, the coldest month, daytime reductions ranged from –0.61°C to –2.22°C, with negligible nighttime changes. In July, the hottest month, daytime reductions reached –4.74°C (soilless) and –3.51°C (soil), with nighttime decreases up to –1.70°C. Seasonal analysis showed winter daytime cooling up to –3.02°C and summer cooling up to –4.38°C. Results demonstrate the strong potential of green roofs as a sustainable cooling strategy in hot climates, with soilless systems generally achieving greater temperature reductions. These findings have significant implications for sustainable urban development in Abu Dhabi and other desert regions, supporting national goals for reduced energy use, improved thermal comfort, and enhanced environmental quality.