The main focus of the research is the study of the indoor microclimate in historic buildings: its modifications and control, improving the management of the factors which characterize it. Indeed, the state of a historic building’s conservation highly depends on its microclimate. Moreover, we will study the outdoor microclimate, and in particular the effects of vegetation on it in archaeological areas. The research aims to propose the application of a specific methodology that allows studying the outdoor microclimate in historical places and guarantees the preventive conservation of the architecture and the valuable artefacts guarded within through the knowledge and understanding of the importance of the indoor microclimate. This approach aims to guarantee or improve – as appropriate – the energy efficiency of heritage buildings, too. The methodology will be applied to national and international case studies. This is why another goal of the research is to define two risk indexes: The Heritage Microclimate Risk (HMR) and the Prevision of Risk of Damage (PRD), which allow evaluating the risk level of the indoor environment and the risk the artefacts are exposed to. The decision to explore the topic with the latter in mind derives from the fact that the best strategy for the conservation of heritage assets is to identify – in good time – situations where there is a risk of damage to the artefacts due to the microclimate, by defining alarm thresholds and strategies to counteract this risk.