Silica aerogels are high-performance thermal insulation materials that can be used to provide unique solutions in the envelopes of buildings when space is limited. They are most often applied in historic buildings due to thin insulation thicknesses and since they are compatible with historic structures. In 2021, the first Aerogel Architecture Award was held at Empa in Switzerland in order to collect, evaluate and award outstanding uses of this relatively new building material. From the submitted projects, three were selected for an award by an expert jury. They showcased applications in which heritage protection and the conservation of a building’s character and expression were reconciled with significant improvements in the energy efficiency of the building. The submissions also showed that a broader communication of these types of solutions is important in order to provide more information and security to planners and heritage offices and to facilitate the application of these materials in the future so that they can contribute to the protection of cultural heritage and reductions in the operational and embodied emissions of our building stock by extending the life expectancy and energy efficiency of existing buildings.

While traction energy is the main energy used in passenger trains, the energy required to condition the passenger area is significant and can account for up 40% of the total energy use. Due to space constraints, passenger train envelopes are usually only insulated with a few centimetres of conventional insulation materials, leading to relatively high U-values and high energy transmissions in climates where heating or cooling is necessary. Here, the use of superinsulation materials in trains for heating/cooling demand reduction was evaluated. Selected commercially available superinsulation materials were screened and benchmarked in terms of thermal conductivity, fire safety, behaviour under vibration and preferred use position within the train envelope. Both the specific vacuum insulation panels and silica aerogel boards that were tested were found suitable for the application in train envelopes in terms of their thermal, fire and mechanical properties. While vacuum panels have the best insulation performance, aerogel boards offer higher flexibility during installation and reduced risk of damage-related performance loss. Both materials can greatly enhance the energy efficiency and thermal comfort of trains and can be implemented cost-neutrally. However, new policy frameworks are likely to be necessary to promote energy efficiency and the broad implementation of thermal superinsulation in trains.

Research on sustainability in the building sector currently focuses mainly on technical solutions while little attention is given to how behaviour influences the uptake of these solutions. Bounded rationality may have a significant impact on the effective implementation of more sustainable technologies that are already available. However, empirical evidence on the effects of bounded rationality in the building sector, such as cognitive biases, is still lacking. Here, we present an empirical investigation of four cognitive biases in the building environment, namely the framing, anchor, default, and decoy effect. For that, energy-related decisions situations were presented to approximately 270 participants in an online survey. Our results show that awareness of greenhouse gas emissions from buildings can be raised through framing that the willingness to pay more for an energy-efficient home can be increased by presenting it as default, and that the choices can be shifted towards more energy-efficient appliances by using a decoy. The hypothesis that anchoring increases the willingness to pay more for the installation of a solar system could not be supported. These findings decrease the lack of empirical data on cognitive biases in the context of buildings and further indicate the potential of choice architecture in the building environment. The influence of cognitive biases in energy-related decisions should be used to increase the adaptation of sustainable technologies.