Due to the aerogel's favourable building physical properties – water vapour diffusion open, non-flammable – aerogel insulation is ideally suited for the retrofit of historic buildings. Here, thin layers of the material can have a large impact on energy efficiency and comfort while keeping the appearance of the building the same. This is not possible with conventional insulation materials. A detailed discussion of the use of aerogel in heritage buildings is given in Ganobjak et al., 2020 [1].

Thermal superinsulation in general, and aerogel specifically, is also a good material choice to increase densification of inner-city areas. In fact, where space is limited and expensive, for example in many Swiss cities, aerogel can generate additional financial value by creating more usable space inside a building [2]. Together with AGITEC AG and ERNE Holzbau AG we developed an ultrathin aerogel-wood element which is ideally suited for these contexts. These elements have been applied in the NEST Sprint unit (Empa - NEST - SPRINT).

Another approach to use aerogel in buildings is to use it as filling in insulating bricks. Insulating bricks constitute an interesting alternative to the common approach of a layered construction as they incorporate both the structural and the thermal functions of the building envelope. Commercially available insulating bricks usually have thermal conductivities of 70-90 mW/(m·K) or more. Filling such a commercial brick with insulation based on aerogel granules, we reduced its equivalent thermal conductivity from 91 down to 59 mW/(m·K), corresponding to a U-value of these “aerobricks” of only 0.157 W/(m²·K) at a thickness of 365 mm [3]. Hence, using aerogel, the thickness of insulating bricks can be reduced, thus gaining space and opening up new architectural possibilities.

One impediment to the usage of aerogel in the building sector is the lack of knowledge on aerogel materials and products with building professionals. Because risks and potentials of these new materials are not known widely in the sector, many opportunities are missed where aerogel would bring an added value in terms of comfort, energy or financial savings. To ameliorate this situation, Empa has created an independent website that provides information on the most common aerogel products available in Switzerland. Furthermore, examples of applications in the build environment are given. The website is geared specifically towards building professionals and can be found here: www.aerogelanwendungen.ch

Besides its application in buildings, aerogel is also a suitable material for the use in transportation. Here, its high insulation performance is very useful in the optimal use of the little available space [4].

[1]         M. Ganobjak, S. Brunner, J. Wernery, Aerogel materials for heritage buildings: Materials, properties and case studies, J. Cult. Herit. 42 (2020) 81–98. https://doi.org/10.1016/j.culher.2019.09.007.

[2]         J. Wernery, F. Mancebo, W.J. Malfait, M. O’Connor, B.P. Jelle, The economics of thermal superinsulation in buildings, Energy Build. 253 (2021) 111506. https://doi.org/10.1016/j.enbuild.2021.111506.

[3]         J. Wernery, A. Ben-Ishai, B. Binder, S. Brunner, Aerobrick — An aerogel-filled insulating brick, Energy Procedia 134 (2017) 490–498. https://doi.org/10.1016/j.egypro.2017.09.607.

[4]         J. Wernery, S. Brunner, B. Weber, C. Knuth, M.M. Koebel, Superinsulation Materials for Energy-Efficient Train Envelopes, Appl. Sci. 11 (2021) 2939. https://doi.org/10.3390/app11072939.