# Integrated Deep Renovation of Existing Buildings with Prefabricated Shell Exoskeleton
## 3 Application to a Real Case Study
### Design of the Holistic Retrofit Intervention
#### 3.2.2 Improvement of Energy Efficiency  
The objective of the energy-efficiency amelioration measures was to reduce the building's consumption and improve thermal comfort. This was obtained from insulation systems aimed at both reducing the transmittance levels of opaque surfaces to be lower than the maximum thresholds envisaged for buildings subject to energy requalification (in Brescia, equal to 0.28 W/m\({}^{2}\)K for vertical structures and 0.24 W/m\({}^{2}\)K for inclined structures or roofing) [41], as well as keeping the total thickness of the AdESA system within the limit of 25 cm, which is the maximum thickness of the thermal layer envisaged by the Italian Standard to allow for derogation from distances between buildings required by the codes [42].  
In order to design the intervention, the stratigraphy of the existing walls and of the additional wooden layers on the roof and along the short side of the buildings was taken into account. To improve the design, different solutions were evaluated, considering different types of insulating material and thicknesses, to obtain a homogeneous thermal transmittance. The value of transmittance, in addition to influencing the thermal dispersion, also played a pivotal role in the definition of comfort for users by maintaining the internal surfaces at a similar temperature in all directions.  
The final energy intervention consisted of an additional layer of the AdESA system to be superimposed on the structural shell. The energy layer was composed of: a 10-centimeter thick layer of PIR (polyisocyanurate) insulation panels on the roof, with an additional sloped layer to correct the water runoff problems; an 8-centimeter-thick layer of EPS insulation panels along the short side of the building corresponding to the CLT panels, and new sliding doors and windows with electro-colored thermal break aluminum frame and double-glazing inside the steel frames; a 10-centimeter-thick layer of EPS insulation panels along the longitudinal side of the building, covering the existing precast panels. A thin layer of plasterboards was interposed between the EPS and CLT panels along the short sides for fire protection (class A1 for reaction to fire). All the walls were finished with painted plaster.  
The results obtained for the considered energy intervention, estimated through dynamic simulations, are shown in Figure 19, in terms of monthly heating and cooling demands, and in Table 3 in terms of transmittance. The annual energy savings for the heating is equal to 50.51% with respect to the as-is situation, with a peak thermal load of 26 kW and an annual thermal load of about 31,000 kWh [16].  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Insulation System** & **Transmittance** & **MaxTransmittance** \\  & & **[W/m\({}^{2}\)K]** & **[W/m\({}^{2}\)K]** \\ \hline Transversal short walls & & & \\ (North and South) & & & \\ Longitudinal long walls & & & \\ (East and West) & & & \\ Roof & & & \\ \hline \hline \end{tabular}
\end{table}
Table 3: Results of the dynamic analyses for the energy intervention (AdESA 2019).