Abstract Buildings are one of the leading energy consumers in Europe. To improve energy efficiency in the built environment means to optimise the operation of building systems. Acoustics potentially provide an important information source to support the assessment of the operation of buildings. Recently, different approaches to the application of acoustic sensing technology have been studied. This paper presents an overview of three on-going projects which look at how sounds can be utilized to reduce energy consumption in buildings. In the “Sounds for Energy Control of Buildings” (S4ECoB) project the primary goal is the establishment of more energy-efficient buildings through the optimization of existing BMS. The “Experimenting Acoustics in Real environment using Innovative Test-beds” (EAR-IT) project aims to develop acoustic mass flows maps which provide awareness of the flows of masses. The “Energy efficient & Cost competitive retrofitting solutions for Shopping buildings” (EcoShopping) project purpose is to increase the energy efficiency of a building and to optimize the investments necessary in building retrofitting. Diverse methodologies and technologies (wired, wireless and mobile) are tested in realistic conditions provided by each demonstrator.