# The Evaluation of Historic Building Energy Retrofit Projects through the Life Cycle Assessment
## 5 Life Cycle Assessment
For Scenario A (rebuilding of roof membranes with FPO/PVC-P waterproofing reinforced with polyester, the introduction of a second window frame for all the windows inside the building, and exterior facade plastering with a breathable product), the category \"materials extraction (A1-A3)\" had an impact of 33,734 kg of CO\({}_{2}\), whereas for \"replacement (B4-B6)\", it was 11,169 kg of CO\({}_{2}\). \"Transportation (A4)\" and \"End of Life (C1-C4)\" had CO\({}_{2}\) impacts of 105 kg and 74 kg, respectively (Figure 5). This scenario changed when entering data about the \"operational energy\" of 260,000 KW/h (according the Termus). In this way, the global warming kg CO\({}_{2}\) (related to \"operational energy\") was 7,854,186 kg of CO\({}_{2}\) (Figure 6), which was a much higher value than the A1-A3, B4-B6, and C1-C4 categories, producing 7899 tons of CO\({}_{2}\) (Figure 6). \begin{table}
\begin{tabular}{c c} \hline \hline
**Main Factors Influencing Embodied Carbon** & **Case Study Data** \\
**the Building** & \\ \hline Address & San Giorgio a Cremano (NA), Italy \\ Type & Historic or protected monument \\ Age/period, year built & 1700 \\ Construction typology & Bearing masonry (tuff) \\ Use (residential, commercial, hotel, school, hospital) & Currently used by Telematic University Pegaso. \\  & Original use: civil residence \\ Number of buildings on site & 1 \\ Number of floors & 3 \\ Gross floor area (m\({}^{2}\)) & 1200 square meters \\ \hline \hline \end{tabular}
\end{table} 
Table 4: BIM modelling basic information. For this reason, the first design project was not satisfying in terms of CO\({}_{2}\) emissions. Therefore, a second design project was proposed, based on energy retrofitting criteria, to lower CO\({}_{2}\) levels caused by the energy supply. In Scenario B, to the interventions of Scenario A were added some energy retrofit solutions: photovoltaic panels and a thermal coat on the internal facade of the building with \"expanded polystyrene insulation panels\", as discussed in the first paragraph (state of the art). It was provided for the inclusion on the roof of 40 photovoltaic panels that cover an area of 60 m\({}^{2}\) on the roof, and they were able to produce 9452 KWh/y of renewable primary energy (as required by the Termus software). In this way, the \"materials extraction (A1-A3)\" category impacts were 126,353 kg of CO\({}_{2}\), whereas for \"replacement (B4-B6)\", it was 32,024 kg of CO\({}_{2}\). \"Transportation (A4)\" and \"End of Life (C1-C4)\" had an impact of 232 kg of CO\({}_{2}\) and 13,261 kg of CO\({}_{2}\), respectively (Figure 7). This scenario changed when entering data about the \"operational energy\" of 236,010 KW/h. This value started to decrease compared to Scenario A, thanks to the production of green energy produced by the panels and the installation of the thermal coat (Figure 8). In this way, the global warming kg CO\({}_{2}\) (related to \"operational energy\") was of 7,129,486 kg CO\({}_{2}\), producing 7301 tons of CO\({}_{2}\) (Figure 8). However, there was a problem. The value of \"materials extraction (A1-A3)\" was much higher than in Scenario A, i.e., 33,734 kg of CO\({}_{2}\) compared to the 126,353 kg of CO\({}_{2}\) of Scenario B.  
Figure 5: Scenario A: Global warming kg CO\({}_{2}\)-life-cycle stages. Figure 6: Scenario A: Global warming kg CO\({}_{2}\), calculated considering the amount of operational energy. This occurred because the installation, maintenance, and disposal of photovoltaic panels and thermal insulation required a higher CO\({}_{2}\) expenditure over the whole life cycle of the building material. It is true that the amount of \"energy use\" started to decrease in Scenario B, but at this point it was necessary to reason about materials in order to arrive at a more sustainable and circular design scenario. Thus, the third project scenario (Scenario C) was proposed. The planned project interventions were the same as Scenarios A and B, but the thermal coat was now made of hemp panels as discussed in the first paragraph (state of the art).