A measuring campaign of thermal conductance in situ and possible impacts on net energy demand in buildings

In the last years many studies concerning the evaluation of the thermal conductance of building elements via measurements have been carried out; this value has to be ensued from the analysis of recorded temperature and heat flux profiles. The determination of this property in situ would allow a more accurate a more accurate evaluation of the real heating energy demand of a building. Papers discussing different data analysis methods are present in literature and measurements on test components under real conditions and evaluations on different theoretical aspects by means of numerical simulations have been already developed. This paper aims at widening the existent literature of the in situ evaluation of the thermal conductance, through the discussion of the results of a measuring campaign which lasted four years on real buildings, and by comparing the reference specific thermal conductance (C) values with those computed on the basis of the measurements. Various tests on the same elements are discussed. Finally an analysis on the influence of the C value on the evaluation of the net heating energy demand of a building in different climates is presented.

► A campaign of four years in situ measurements is presented.
► The error in measurements has been estimated.
► Thermal conductance has been evaluated by using all methods in literature.
► A correlation between measured and design thermal conductance has been evaluated.
► The real thermal conductance leads to an increase of about 12% of the net energy demand for heating.