Stricter energy regulations for energy use in buildings require new construction to be equipped with increasingly thicker insulation layers and minimal surfaces for glazing in cold climates. In recent years a new type of window has been proposed as a way to overcome the notoriously low thermal performance of transparent surfaces. In order to reach such performances, this glazing type has been equipped with monolithic aerogel as the glass-pane filling.

The scope of this study is a comprehensive analysis of greenhouse gas emissions from the partial substitution of typical triple-glazing-with-argon units with double-glazing-with-monolithic-aerogel units in residential building upgrades.

A social housing complex from the late 1960s, located in Oslo, is used as a test case. The building is fully upgraded using passive house solutions. The new facades have walls with a U-value of 0.10 Wm-2K-1 and triple-glazing-with-argon units with a U-value of 0.79 Wm-2K-1. In this study approximately 30% of the glazing area is substituted with double-glazing-with-aerogel units with a U-value of 0.50 Wm-2K-1. A cradle-to-grave analysis is performed on the facade components to determine the global warming potential of the two proposed glazing options. Differences in the share of the embodied emission over the building lifetime when increasing the total window-to-wall ratio from 24% to 33% and to 50% are also investigated. In addition, various maintenance schedules are used to evaluate the differences in emissions embedded in the façade components. Comparisons between the resulting energy demands and embodied emissions are presented.

Preliminary results show how the option with aerogel glazing is effective in reducing the annual heating demand by 7%. This increases to 18% for the façade design with a 50% window-to-wall ratio. The better insulation value of aerogel glazing effectively reduces the thermal losses while at the same time allowing passive solar gains. In addition, the mass of aerogel employed for glazing insulation does not significantly change the total embodied emissions of the façade. This suggests that the use of this window type is environmentally positive.