As people spend up to 90% of their time indoor; exposure to poor Indoor Air Quality (IAQ) may negatively affect their health. Moreover, the COVID19 pandemic has revealed the profound social vulnerability of certain groups in society, particularly those struggling with poor health conditions. Additionally, the external air temperatures in the UK are expected to rise by over 5°C by 2070, as a result of climate change, with the frequency and intensity of heat waves also expected to increase. Rising external temperatures increase significantly the risk of overheating, cooling load, energy consumption in buildings and associated carbon emissions, with the problem being particularly affecting health and wellbeing of vulnerable populations including children and older occupants of buildings. There is therefore an urgent need to address this multi-faceted knowledge gap by developing effective interventions that improve health and living conditions in homes occupied by vulnerable populations. The project aims to fill a knowledge gap in evaluating and improving indoor air quality (IAQ) and thermal comfort in council homes. The purpose is to ultimately develop technical-behavioural interventions that improves people's health, indoor environmental conditions, and reduces energy consumption and associated carbon emissions. We anticipate the project will have a positive impact on housing design policies, as well as increase public awareness on the necessity for behaviour change to achieve net zero carbon targets, whilst improving occupants' health and wellbeing.