Chapter One - High Thermal Resistance Versus High Thermal Capacity: The Dilemma

Abstract

The heating and cooling load of a building is mostly due to the heat transfer across its envelope and thus selecting an appropriate envelope is one of the most effective ways to achieve energy saving. For many years, improving the thermal performance of envelopes meant adopting a thick insulation layer, regardless its position or the presence of mass. These new envelopes act as thermal barriers causing summer overheating and attributing the regulation of indoor comfort to conditioning systems. Forty years of researches have demonstrated that thermal inertia is one of the most important parameters to improve thermal comfort as well as to reduce cooling energy demands especially in particularly dynamic external and internal (e.g., used intermittently) environments. On the other hand, the recent literature on sustainability highlights that, considering economic and environmental aspects, lightweight solutions should be preferred.