Executive Summary This report examines ASEAN’s building sector and the many opportunities that it offers for increased energy efficiency. The ten countries that make up ASEAN are diverse: the region contains some of the largest countries in the world by population, small highly developed city states, and a number of fast-growing economies with rapidly emerging middle classes. The report focuses mostly on the largest five of these markets: Indonesia, Malaysia, the Philippines, Thailand and Vietnam. While their energy circumstances vary, the countries of ASEAN have one thing in common: increasing pressures on their energy systems, from ongoing economic and industrial growth, infrastructure and capacity constraints, a reliance on energy imports, and rising incomes leading to increasing demand for energy using appliances. Taken together, and with ASEAN countries expected to add building floor space of as much as 22 billion m2 by 2060, optimizing energy use in buildings is therefore becoming an increasingly recognized policy priority in the region. Cooling is the most significant demand sector, accounting for a large percentage of energy usage and expected demand growth across the region, and penetration rates for air conditioning in many countries remain very low. ASEAN has set some relatively ambitious targets for energy efficiency, both as a region and at an individual country level. Member states aim to reduce energy intensity based on 2005 levels by 20 per cent in 2020, and 32 per cent in 2025. Recent progress towards these targets has been steady based on some countries moving towards more service-based, less energy intensive economies, and others moving away from inefficient traditional energy consumption at the household level. There has also been a raft of supporting policy introduced to encourage energy efficiency in recent years. While many different initiatives have been supported, across building benchmarking, auditing schemes, building codes, green certification systems, financial incentives and support for the energy services company (ESCO) sector, many of the initiatives have been piecemeal, thinly resourced or poorly enforced, meaning that building energy efficiency’s potential is largely untapped. The exception to this is Singapore, which is a world leader in both building efficiency policy and implementation, and research and development into technologies and techniques that may be of broader interest to the region. There are many positive developments in ASEAN related to more efficient buildings. For example, new law in the Philippines promises to catalyze actions by making it mandatory for building owners to report on opportunities. There has been a promising growth in green bonds issued specifically for green building projects. And there is an enormous range of support and financial resources provided by development agencies and investors, both in terms of technical assistance to governments, and facilitation support and financing for the nascent building energy efficiency industry. The report analyzes each of the countries in the region and sets out their national circumstances, policy settings, particular opportunities and key active stakeholders. Based on this research, it concludes that the following topics are some of the most promising areas for further research and development to progress building energy efficiency in the region:• Consistent approaches and common methodologies for classifying types, status and energy performance of the building stock. • ESCO sector development assistance, to improve confidence in energy savings for retrofit projects. • Financing for building energy efficiency through green bonds. • A focus on innovative cooling and air conditioning technologies, which as a research theme, could focus on business models (e.g. ‘cooling as a service’), technology (e.g. research into non-vapor compression types, automation and control systems, improving the use of natural ventilation and other passive cooling strategies, and advanced window coatings), policy and standards. • Harmonization of building codes and ratings. • A focus on Indonesia, Philippines and Vietnam as the locus of impact for policy and finance-related initiatives. • Better information on the economic benefits of building energy efficiency, including the multiple resultant social and economic co-benefits that might accrue alongside energy savings.Further scoping work in any of these recommended areas would need to be undertaken, to design interventions and identify partners and take actions forward.