The contribution carried by the appraisal discipline for the purpose of disentangling the embodied energy issue

In the disciplinary field of real estate appraisal, the cost estimates of the construction materials and building works are long since well established, and they rely upon a considerable basket of qualified sources. While assessing projects, particularly through the methodological framework which involves the bill of quantities, we are used to referring to exhaustive inventories of the costs to be incurred. Such widely available data sources specify the characteristics of the materials to be employed during the laying process, as well as of the works to be carried out, and report the related costs per unit weight, volume or surface area.In a research we developed, we aimed at deeply examining the relation between the aforementioned costs of building materials and their embodied energy. The latter is defined as the energy load needed to mine the raw materials, to manufacture the semi-finished goods, as well as to transport them to the construction site. As it was expected according to outcomes discussed by the relevant literature, we found evidence of a positive relation between the cost of the construction materials and their embodied energy. Nevertheless, the linear functional form is not appropriate, since such a model does not provide statistically significant results. On the contrary, adopting a log-linear function, the interpolation curve fits much better to the data, hence the cost of the construction materials may be regarded as a reliable predictor of their embodied energy.This research branch requires performing a range of intensive trials, in order to get a more acute awareness of how much the results are generalisable. The preliminary findings bring out several interesting considerations, which in turn entail - or at least suggest - further investigations: firstly, the accuracy level of the model, namely the quality of the interpolation and the stability of the results, significantly increases by defining clusters of the building materials with reference to the sub-sectors they belong to; secondly, the items belonging to the raw material industry show conflicting results, that is to say, an inverse relation between the cost and the amount of embodied energy.