Embodied carbon minimisation of retrofit solutions for walls

Energy saving in a building is mainly a function of the performance of building insulation and equipment. However, initial embodied carbon dioxide emissions increase as the operational energy decreases, so selecting the best energy retrofit solution should take this into account, together with building-specific needs. Currently there is no regulation of embodied carbon dioxide emissions in the European Union construction industry. The effectiveness of a low-carbon dioxide emission project should be judged by its energy in use together with the building-specific needs, not the total of the energy expended in its retrofit. Three different buildings with different occupant behaviours were studied, and five different retrofit solutions for the external rendering of walls were tested. The objective was to establish a relationship between the initial embodied carbon dioxide of a retrofit solution and the real operational energy consumed. A probabilistic approach was developed to predict the number of years that each solution takes to reduce the embodied carbon dioxide to 0·15 kg/kWh of operational energy in each building. The use of cork in mortars represents the most positive measure to reduce embodied carbon dioxide and increase energy efficiency.