1. School of Technology and Management, Dept. of Civil Engineering, Polytechnic Institute of Viseu, Campus Politécnico de Repeses, 3504-510 Viseu, Portugal (corresponding author).
2. Faculty of Engineering, Dept. of Civil Engineering, Univ. of Porto, Laboratory of Building Physics, Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal.