Low Energy Cooling and Ventilation for Indian Residences (LECaVIR) Energy security, climate change and economic growth are matters of critical international importance which are affecting billions of people around the world. The way they are tackled impacts on the sustainable infrastructure of our planet. One of the most significant global development challenges is how we mitigate against the proliferation of energy intensive air-conditioning (AC) for cooling and ventilation in buildings in response to a globally warming world and the greater expectations for thermal comfort in buildings that accompany growing affluence. This is particularly pertinent in developing countries such as India as disposable income increases, making AC more easily accessible. Many of India's most populous metropolitan areas such as Mumbai, Chennai and Calcutta have hot and humid climates, and are seeing growth rates in the use of AC of approximately 30% per year. The electricity demand for space cooling comprises up to 60% of the summer peak load in large cities such as New Delhi, and most air-conditioners are inefficient and use refrigerants with high GWP (global warming potential). A solution to this problem is needed urgently. This makes energy efficiency and thermal comfort a priority area for the Indian government in recent revisions of its National Building and Energy Conservation Building Codes which emphasise the need to design buildings for natural ventilation (NV) and mixed mode (MM) operation. The floor area of Indian buildings is expected to increase by 500% by 2030. Without the knowledge of how to achieve comfortable, cooler conditions through ventilating these new buildings effectively and efficiently, AC will continue to be specified, installed and used copiously. The UK is just as vulnerable to these adverse trends, and similarly needs to address the unsustainable increase in portable AC in homes. This project will develop building designs comprising low energy cooling and ventilation technologies that employ smart self-learning control algorithms to provide countries like India with viable market solutions.  For each climatic zone in India, the project will quantify the periods of the year (or day) for which NV is likely to be feasible. For those periods when NV is unlikely to work, such as hot, humid (monsoon) periods, MM solutions, using a combination of NV, low energy cooling and AC systems will be developed and tested. Although it is inevitable that some AC will be necessary, there is significant scope within this project to work with technologies which are more energy efficient and which use fewer GWP chemicals or eliminate their use altogether. Once the NV and MM strategies are established, the work will focus on developing building energy management systems for controlling these hybrid systems to optimize building energy use. This will involve deciding when to switch between building operation modes, when to start AC systems, and which key variables should be controlled. These algorithms will also have self-learning capability which will automatically and continuously improve the operation of a building.  There will be three significant outputs from the project: (i) guidance for developing and sizing low energy cooling and ventilation strategies in residential buildings in India to help architects, engineers and facility managers design and operate buildings; (ii) smart self-learning control algorithms for use in building energy management systems, capable of optimizing energy use in residential buildings and which will be adopted by the building automation industry; and (iii) design tools for predicting the likely performance of buildings based on these new strategies which will be used to inform policy directives by encouraging lower energy cooling systems as part of code compliance. Our impact plan ensures that these market-ready building design and control solutions are capable of rapid adoption by our collaborators and industry partners for market deployment in Indian residences. The Global Challenges Research Fund (GCRF) supports cutting-edge research to address challenges faced by developing countries. The fund addresses the UN sustainable development goals. It aims to maximise the impact of research and innovation to improve lives and opportunity in the developing world.