## 8 Conclusions  
This concept paper has reported on the application of the indoor soundscape approach to the research field of acoustic comfort in naturally ventilated residential buildings. In this study, the following three questions were raised: (i) What does the indoor soundscape conceptual framework represent? (ii) What limits can be identified in the current approach towards acoustic comfort under NV conditions in residential buildings? and (iii) How can the highlighted limits be overcome by the application of the indoor soundscape approach to the NV context? With respect to the first research question, the indoor soundscape framework has been introduced by referring to the most recent research. Indoor soundscape characterizes how people perceive, experience, and understand the indoor acoustic environment in the context of their working, living or leisure environments, with the aim of designing positively perceived indoor acoustic environments. As compared with the soundscape concept, as originally investigated and developed from urban studies, the building itself plays a fundamental role in defining the three pillars of the indoor soundscape concept. Indeed, the building enclosure demarcates the boundary and the connections between the indoor and the outdoor (i.e., \"context\"), depending on its geometry and materials, it filters outdoor sounds and shapes the indoor acoustic environment (i.e., \"acoustic environment\"), and depending on its function, it contributes to building users' expectations and needs (\"people\"). Acoustic criteria required for naturally ventilated residential buildings have been reviewed, and a summary of the facade noise control solutions developed so far to meet those criteria have been provided. Acoustic criteria were found to be based on indoor noise level reduction, typically without a distinction based on ventilation strategy. With respect to the second research question, the outcomes of the analysis indicated two main limits. First, a fragmented view towards indoor environmental quality has resulted in acoustic criteria that does not consider how buildings are designed and operated to meet multiple needs other than acoustical ones (e.g., ventilation, visual, and cooling needs) and how people respond to multiple simultaneous environmental stimuli. Secondly, the lack of a perceptual perspective has resulted in acoustic criteria that neglects the multiple cognitive and behavioral factors impinging on comfort in naturally ventilated residential buildings. The literature suggested that factors such as the connection with the outside and the sense of control over one's environment may induce \"adaptive acoustic comfort\" opportunities, but these aspects need to be further addressed by the research community to find scientific evidence. In any case, the mere use of sound level limits is not enough to reflect the acoustic perception of indoor environments and this suggests the inadequacy of their use to define criteria tailored to the complex user-building interaction that can occur under NV conditions. With respect to the third research question, the discussion suggested that under the indoor soundscape perspective there seems to be a potential to solve the current apparent conflict between ventilation and acoustic needs impeding the adoption of NV strategies on a large scale. In fact, by underpinning a perceptual perspective (the \"people\" pillar) and by contextualizing the perceptual experience (the \"context\" pillar), the indoor soundscape appears to be a framework able to overcome the underlined current limits. Rethinking NV under the indoor soundscape framework means to value it as a strategy to transmit, block or adjust outdoor sounds in order to provide a connection with the outside, release wanted sounds or mask unwanted sounds.