Throughout the world and especially in emerging countries, museums are increasingly undergoing development, which promotes the construction of buildings with significant architectural expressions and diverse cultural activities. Interior environment in museums is defined by two important requirements: the preservation of works of art, and the comfort of visitors or individuals who work in these buildings. The research problem under investigation originates in the fact that some works of art on display have hygrothermal needs that in most cases do not correspond to the environmental comfort conditions required by visitors and those who work in exhibition spaces. This article presents standards and ranges of conflict in interior climate in museums, and measures these requirements using environmental records and visitor surveys. The methodology employed was based on the "Simultaneousness Index" proposed in Italy in 2008, and was extended to museums located in different climatic zones. Using this method, the conditions in three contemporary art museums concentrated in the humid subtropical climate of Brazil were reviewed in order to examine the required environmental parameters, verify the simultaneity of artwork-visitor hygrothermal satisfaction, and discuss formal characteristics in relation to energy demands. The cases studied were the FIC (Porto Alegre), the MON (Curitiba), and the MUBE (Sao Paulo). The results show the performance of environmental compatibility for winter and summer, and suggest the influence of architectural strategies on thermal comfort satisfaction and energy demand.