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Buildings energy audits ask for a thorough analysis of the audited object. According to standards EN 16247, all the factors affecting actual energy consumption must be assessed and estimated. One of the hardest contributions to be quantified is air change rates of buildings, particularly when no mechanical air supply system is installed. In this case, just air leakages through the external envelope and users' behaviour (e.g. opening of doors and windows) will determine the actual figures of air change rates. As a consequence, no direct measurement can be made. Among the indirect measurement approaches, the procedure using the decay of indoor carbon dioxide concentration provided good results, as described in literature. However, a number of disturbing factors must be considered, because they affect the transient behaviour of air exchange between indoor and outdoor. This paper will provide more insights into the possibility of developing a testing kit for the energy auditor, so that they can evaluate air change rates of buildings through quick on-site surveys in the audited object, then the information thus collected can be used as an input for the energy audit process. Such a challenge requires the development of a quite cheap, easy to install and low invasive monitoring kit, which is based on state-of-the-art wireless and low power monitoring technology. In addition, data analyses must be quick and partially automated. Finally, a preliminary test performed in a room of the Engineering Faculty at the Università Politecnica delle Marche in Ancona (Italy) will be reported.

-Public administrations are encouraged to adopt actions for energy requalification of public buildings, which are responsible for considerable amounts of energy consumption. Low-cost technology improvements for energy renovation with high return on investment is a good opportunity when resource shortage hampers the adoption of expensive refurbishment. To this purpose, the integration of advanced control policies may optimize energy use of buildings with minimum hardware enhancement.In this contribution, we evaluated the performances of a control system based on fuzzy logic, supervising local Proportional-IntegrativeDerivative (PID) controllers, through numerical simulation. First, the design process will be described, with particular concern to the proper selection of the rules in the knowledge base and the design of the inference engine. Then, its performances will be compared with the ones provided by the use of just ordinary PID control units. The fuzzy based control system was simulated as an addiction to the heating system of an existing small public building, that is the "San Elpidio a Mare" community clinic located in Italy. The performances were assessed by means of simulations of an energy dynamic model developed in the Dymola TM environment, that had been previously validated with real consumption measurements. In this paper we will show not only what energy saving can be obtained by means of the fuzzy supervisor, but also its satisfactory performances in terms of stability of the control outputs.