According to the India Energy Security Scenario 2047, the number of residential air conditioner (A/C) units may increase seven-fold by 2037 as compared to 2017. Also, the related energy consumption might increase four times in the next two decades, according to India’s National Cooling Action Plan. Therefore, the study of occupant cooling behaviour is essential to reduce and manage the significant electricity demand, helping to formulate and implement climate-specific cooling policies, and to adopt low-energy and low-cost technologies at mass-market scale. The study aims to analyse residential electricity consumption in order to investigate occupant behaviour, especially for thermal comfort by using space cooling and mechanical ventilation technologies. Among the five climate zones in India, this study focuses on the occupant behaviour in a warm-humid climate using Auroville as a case study, where climate analysis of the past 30 years demonstrated progression towards unprecedented warmer weather in the last five years. In this study, electricity consumption data from 18 households (flats) were monitored for seven months (November 2018–June 2019). The study also elaborated the limitations faced while monitoring and proposed a data filling methodology to create a complete daily profile for analysing occupant behaviour through electricity consumption. The results of the data-driven approach demonstrated the characteristics and complexities in occupant behaviour and insight on the operation of different technologies to attain thermal comfort in residential buildings in an increasingly warming climate.

Of the 33 global megacities, 10 were situated in South Asia. Extreme heat waves have become an annual phenomenon due to climate change in South Asian megacities, causing severe health issues and even deaths. In this study, we evaluated 29 years (1990–2019) of historical data on heat stress in ten selected megacities (existing and prospective)—New Delhi, Dhaka, Mumbai, Kolkata, Ahmedabad, Chennai, Bengaluru, Hyderabad, Chittagong, and Pune—in India and Bangladesh. We used heat index (HI) and environmental stress index (ESI) analyses to evaluate stress and vulnerability. Our results showed New Delhi, Mumbai, Kolkata, Ahmedabad, and Chennai in India; Dhaka and Chittagong in Bangladesh were already experiencing an elevated number of hours of “danger” levels of heat stress, which may lead to heat cramps, exhaustion, stroke, and even death. Furthermore, the frequency of “danger” levels of heat stress and vulnerable levels of ESI has increased significantly since 2011 in the selected megacities, which elevated the heat-related vulnerability among the millions of inhabitants in terms of work hours lost for light, moderate, and heavy work due to heat stress. The vulnerable population in the studied megacities might have to reduce annual work hours by 0.25–860.6 h (light work), 43–1595.9 h (moderate work), and 291–2402 h (heavy work) due to extreme heat in 1990–2019. We also discussed the implication of the work-hour loss on productivity, income, gross domestic product, and sustainable development goal progress because of heat stress and its causes and suggested recommendations to reduce its impact.

A recent, major UK research project investigated technical and social aspects of reducing the CO₂ emissions of UK domestic housing by 50% by the year 2030. As 80% of the UK housing stock that will be present in 2030 has already been built, this study aimed to research the whole life costs of three sets of energy demand reduction technologies for existing housing, over a 25‐year period, suitable to deliver significant CO₂ emissions reduction up to 50%. Demand side technological interventions in the form of fabric upgrades and ventilation systems are identified. Whole life cycle analysis of interventions carried out on two housing variants prominent in the domestic stock under different energy price scenarios is carried out using discounted cash flow and compared with the do‐nothing option. The results show that, despite reducing annual energy bills, there is no clear financial case even over a 25‐year horizon for householders to invest in the proposed interventions that contribute to CO₂ emission reduction targets. When discussed with respect to household income and consumption preferences, the results reveal the need for new policy approaches to overcome the financial and non‐financial hurdles for a mass uptake of energy efficient technologies.