We develop leading capabilities for assessing the health effects of indoor exposures and interventions using housing‑stock simulation and integrated exposure–health frameworks. The modelling theme brings these capabilities together to advance transdisciplinary research into the co‑benefits of net zero indoors, through mechanistic characterisation of indoor exposures and comprehensive health and inequality assessment. We develop an integrated indoor environment–exposure–health modelling framework with holistic metrics for evaluating net‑zero interventions at different scales.