With the enforcement of Emirati energy conservation code, thermal insulation was introduced as an energy efficiency measure. Recently, the autoclaved aerated concrete (AAC) has been presented as a green material masonry that can provide the necessary thermal insulation properties without the use of insulation materials. This work assesses the impact of AAC properties and compares them with a number of possible alternatives, including a techno-economic analysis. This study shows that the density of AAC blocks is about four times lower than that of ordinary blocks with similar size and thickness and is lighter in weight and higher in thermal resistance by about 11 times. At this level of block density, weight and thermal resistance, AAC can satisfy Emirati energy code requirements without the addition of thermal insulation materials. The economic analysis demonstrates the cost-effectiveness of the AAC walls in some emirates and shows a moderate saving-to-investment ratio of more than 3 with a payback time of less than 9 years. This study concludes that the energy use in the residential sector can be reduced by about 7% if AAC walls are used. Each square meter of ACC walls can save almost 350 kg of CO2 emissions throughout its life cycle. (C) 2011 Elsevier B.V. All rights reserved.