## 3 Results
### Compilation and Evaluation of Packages
Those correspond to the three studied DWT and PV systems and the main supply systems as stand-alone systems, which are all discussed in detail throughout this section. Package \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline  & & \multicolumn{3}{c}{**Energy Reduction \%**} & **20** & & & & & **40** & & **60** & \\ \hline
**Element** & **Material** & **Insulation** & **Class/Type** & **1** & **2** & **3** & **4** & **5** & **6** & **7** & **8** & **9** & **10** \\ \hline \multirow{3}{*}{Wall} & Timber & 220 mm & & & & & & & & & X & & \\  & finish & 245 mm & class 37 & X & X & & & & & & X & \\  & 315 mm & & & & & & X & & & & & \\ \hline \multirow{3}{*}{Attic} & Timber & 465 mm & class 37 & X & & & X & & X & & & \\  & floor & 95 mm & class 34 & & & & & & & X & & \\  & finish & 490 mm & class 37 & & & & & & & & X & \\ \hline Ground & Timber & 45 mm & class 37 & X & & & & & & X & & \\ floor & finish & 45 mm & class 34 & & & & & & & X & & \\ \hline Windows & \multirow{3}{*}{Plastic} & \multirow{3}{*}{N.A} & class A & & & & & X & & X & & X \\  & & class B & & & X & & & & X & X & & X \\ \hline \multirow{3}{*}{Terrace door} & Wood & N.A & class A & & & X & & & & & X & \\  & & N.A & class A & & & & & X & & & X & \\  & & N.A & class B & & & & & & & & & \\ \hline Heating & \multirow{3}{*}{Pipe} & \multirow{3}{*}{40 mm } & \multirow{3}{*}{universal} & & & & & X & X & & & \\ and DHW & network & 50 mm & & matts & & & & & & & X & \\ \hline DHW & Pump & N.A & circulation & & & & & & & X & \\ \hline \multirow{3}{*}{Ventilation} & \multirow{3}{*}{0.175} & & \multirow{3}{*}{decentral} & & & & & & & X & \\  & & with heat & & & & & & & & & X \\  & & 0.1 & recovery & & & & & & & & & X \\ \hline \multirow{3}{*}{Sum of individual actions} & \multirow{3}{*}{\% savings} & 20 & 25 & 21 & 20 & 20 & 18 & 39 & 52 & 64 & 66 \\  & Global savings of package & & 11 & 25 & 7 & 20 & 20 & 8 & 39 & 39 & 58 & 52 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Contents and classification of investigated renovation packages. Included building elements in a renovation package are marked with “X”, which is located with respect to the variated element properties. zero represents a change of energy-producing system and/or the addition of renewables, as presented in Figure 4.  
Given the selected boundary conditions for the calculations, 12 of the 308 studied cases satisfy NZEB. Seven of those have W/W heat pumps as the primary supply and five A/W heat pumps. There are 56 solutions lying between the NZEB requirement and renovation class one, while those between the limits for renovation class one and two are 79. As observed from Figure 5, there are a number of cases that are rather close to the NZEB target value of 27 kWh/m2 year but do not reach NZEB. Those have the potential to reach the target by means of model optimization on either the envelope or the producing system's side. Figure 5 reveals a general tendency of increasing global cost with reduction of primary energy demand. Nevertheless, there are also solutions with significantly lowered energy demand that are comparable to the reference case total costs. The results are further analyzed for each main supply system in two ways. First, the addition of renovation packages alone is presented in Figure 6. Second, the packages are combined with the secondary energy production systems in Figure 7. Figure 6 presents the resulting energy demand and NPV by applying the renovation packages defined in Table 2 to the reference energy model. The results are shown for each main supply type, where packages with energy-saving targets of 20, 40, and 60% are marked with an \"x\", a diamond, and a star, respectively. If district heating is kept as the main supply, packages 1-6 (target savings of 20%, based on sum of individual element contributions) provide global savings in the range of 8-25% compared to the reference.