Optimal Thickness for Isolating Foams in Buildings

Abstract

In this paper the calculation methodology for obtaining optimal thickness of polymeric foams EPS, XPS and PU is developed, taking into account investment costs and operating costs in the construction elements, whose thermal transmittance limit is determined by the CTE (BOE, 2006). The use of a thicker insulating material produces a higher investment cost but the energy cost is less. This relationship allows determining the optimal thickness for a minimum total cost. The energy study is conducted with varying monthly temperatures for a reference location and for a period of 10 years. The optimal thickness of the insulating material associated to the minimum cost allows analyzing the influence of the enclosure type, façade orientation and insulating material type. These are the variables which have the most important influence on decision making in the resolution process of the constructive elements design. The study indicates that the insulating material type is the most influential variable in the optimal thickness. The second influential variable is the façade orientation and the third, the constructive solution for the analyzed cases.