Occupant behaviour determines how energy is spent in buildings. In addition to properties of building thermal envelops and technical features of HVAC systems, it can drastically influence the consumption of energy. Applied ICT solutions have been recognised as an essential factor for reducing consumptions and emissions in the operational stage of buildings. However, keeping users engaged is still a challenge to overcome. This paper aims to critically review approaches for user engagement from conceptual and technical points of view and to propose an enhanced engaging procedure. Common user engaging practices provide advices on how to save energy or present feedbacks through a number of solutions. Generally, these solutions detect direct measures through sensors, but barely make information valuable to users. The proposed engaging procedure intends ensuring user commitment through a bottom-up approach based on gaming strategies, conceived upon user-made rules. Basically, by means of a dedicated platform, users are able to define specific rules tackling everyday life actions, experiencing in an active way the use of sensors and actuators. Additionally, a set of rules, generated beforehand by experts for promoting energy saving behavioural changes, is gradually proposed through the platform accordingly to user commitment level. (C) 2017 Elsevier B.V. All rights reserved.