Rising global temperatures and more frequent heatwaves due to climate change have led to a growing body of research and increased policy focus on how to protect against the adverse effects of heat. In cold and temperate Europe, dwellings have traditionally been designed for cold protection rather than heat mitigation. There is, therefore, a need to understand the mechanisms through which indoor overheating can occur, its effects on occupants and energy consumption, and how we can design, adapt, and operate buildings during warm weather to improve thermal comfort and reduce cooling energy consumption. This paper brings together experts in overheating from across Europe to explore 10 key questions about the causes and risks from overheating in residential settings in Central and Northern Europe, including the way in which we define and measure overheating, its impacts, and its social and policy implications. The focus is not on summarising literature, but rather on identifying the evidence, key challenges and misconceptions, and limitations of current knowledge. Looking ahead, we outline actions needed to adapt, including the (re)design of dwellings, neighbourhoods, and population responses to indoor heat, and the potential shape of these actions. In doing so, we illustrate how heat adaptation is a multi-faceted challenge that requires urgent and coordinated action at multiple levels, but with feasible solutions and clear benefits for health and energy.