Economic and Energy Life Cycle Assessment of aerogel-based thermal renders

Abstract The aim of this paper is to provide the Economic Life Cycle Assessment (LCA) of several aerogel-based cementitious thermal insulating rendering mortars, produced in laboratory. This assessment is extremely important because it highlights the need for greater control and a better assessment of the costs of sustainable solutions in construction, namely for energy renovation of the building envelope. Twenty-five laboratory thermal aerogel-based renders were analysed and the following was concluded: the renders with commercial aerogel are the least expensive; the introduction of another lightweight aggregate allows for a reduction of the cost; renders with a subcritical hydrophobic aerogel produced in laboratorial scale are the most expensive but can be optimized in an industrial process. Through the LCA methodology it is possible to ascertain the costs incurred, not only during the production of the mortar but also throughout its whole service life, from cradle to cradle (C2C), including the stages corresponding to its application on the building, maintenance and end-of-life. In addition to the economic evaluation, an energy study was also carried out to highlight the benefits of using these renders in the improvement of the envelope’s insulation, namely the decrease of heating and cooling needs and the corresponding costs over the service life. The wall alternatives that were energy retrofitted with a thermal mortar only provide “economic savings” if a consumption of energy fulfilling more than 10% of the heating and cooling needs is considered. Moreover, the best solution for initial investment was not the one preferred in terms of life cycle economic and energy costs. To sum up, the use of an economic LCA methodology is advantageous in improving the sustainability of the construction, since it facilitates the task of identifying possible improvements based on the study phases and thus the reduction of costs during the life cycle.