The Effect of the Optical Properties of Roofs and Walls on the Thermal and Energy Performance of Residential Buildings

This paper is the second part of a study, whose first part was presented at last year’s ASES Conference [1]. The previous paper was concerned with commercial buildings, while the present one deals with residential buildings. The starting point is the same: the optical properties of the external opaque surfaces (roofs and walls) affect the thermal behaviour of buildings and their energy requirements. The paper explores this complex field with the objective of selecting the optical properties of roofs and walls, granting the best performance, i.e., the minimum energy consumption, given the climate conditions and the other building’s features. The research is based on a vast parametric study, conducted by simulating a residential building, by means of the TRNSYS code, varying and combining a number of parameters. The study has generated several hundred sets of results, allowing comparisons that, in turns, provide guidelines for selecting the best type of skin properties to be adopted in given conditions. A comparison of the results found with the two studies is also presented, showing that residential and commercial buildings behave quite differently, even under the same conditions.