Thermal insulation cost optimality of opaque constructive solutions of buildings under Portuguese temperate climate

Abstract

This work is focused on the identification of the energy and economic optimal thermal insulation solutions of opaque elements of the envelope of buildings located in Portugal. Five different buildings were selected: an apartment, a detached house, a private clinic, a private high school and a medium-sized supermarket. These buildings were supposedly located in three locations, which together represent all climatic possibilities of Portuguese temperate climate. The most common types of thermal insulation were tested, for which three alternative positions within the building envelope(inside, middle, outside) were considered. Thermal insulation thicknesses between 0 (without insulation) and 12 cm were tested.The optimal solution depends on perspective adopted: energy or economic. In terms of cost, the EPS presents the most promising thermal insulation material and its best location is in the middle of the building envelope. Depending on the climatic zone and the buildings’ typology, the cost-optimally thickness varies between 0 and 10 cm and the better energy thickness varies from 0 to above 12 cm. Regions with more intense climate require higher thermal insulation thicknesses. Residential buildings require higher insulation thickness than the others. Buildings with permanent occupation require higher insulation thicknesses than the ones with intermittent use.