## 3 Results
### Compilation and Evaluation of Packages
As indicated at the bottom of Table 1, for some of the packages, the addition of individual savings and resulting savings based on global  
Figure 5: Primary energy as a function of net present value for all investigated packages (308 + reference). energy balance are equal, while for others, they differ. This confirms that the sum of savings of individual actions is not always equal to the global savings. In fact, the comparison between expected and achieved results in Table 2 shows a tendency for greater difference between the results with an increasing number of elements in a package. This is evident as packages 2-5 all constitute of two renovated elements and only for one of these are the global savings lower than the sum of individual actions. Furthermore, a mismatch between global saving and sum of individual elements is also present for packages 1 and 6-10, which comprise three or more elements. On the contrary, package 7 consist of five elements and has equal global and summed energy savings, while package 3 consist of two elements but the sum and global savings differ. This indicates that both the type and number of elements included in the package have an influence on how close the expected and achieved savings are. Figure 6: Energy renovation packages, shown for each of the investigated primary energy supply options. Analyzing the packages with 20% target savings, it can be noted that package 2 provides the most savings for the least cost-increase (25% energy savings for 14% higher NPV compared to reference). Package 6 is the least efficient and the most expensive of the six packages, providing 8% energy reduction but 26% global cost increase. Packages 3, 4, and 5 provide comparable energy savings of approximately 20%, but they vary in NPV. Respectively, there is a 17, 25, and 19% increase in NPV for packages 3, 4, and 5. Package 1 provides an 11% primary energy reduction and 24% increase in NPV. Even though the relative relationship between packages 1 and 6 is similar for all other supply systems, it is noticed that the type of main system can influence their order in respect to cost and energy savings. For example, packages 1 and 6 are nearly equal in terms of energy savings and cost for scenarios with district heating and A/W heat pumps, while for scenarios with gas and W/W heat pumps, their cost differs noticeably. As expected, scenarios with heat pumps bring the largest energy savings compared to the reference (35-50% savings), where in the case of W/W heat pumps, this is enough to satisfy renovation class 2. Figure 7: Selected renovation packages shown for each main supply option. From Figure 6, it becomes apparent that packages 7 and 8 perform equally in regard to energy reduction but with considerably different NPV values. Regardless of the applied supply system, package 7 is substantially cheaper than package 8. A possible explanation of the great cost difference can be contributed to the addition of mechanical ventilation with heat recovery to package 8. It can also be noticed that for scenarios with heat pumps, package 7 is the cheapest of all packages, while for district heating and gas, the cost and achieved savings of package 7 are comparable to those of packages 1-6. Higher energy savings outweigh the additional implementation and running cost for package 7 compared to packages 1-6. This shows that higher energy savings does not necessarily mean greater global cost; moreover, how energy savings are achieved can have a large influence on the total global cost. Considering that the approach for compiling package 7 is purely based on the CEP, sorted across all investigated elements, it can be argued that the approach can yield cost-optimal packages. Packages 9 and 10 compare well in terms of economic and energy performance. Both of the packages include mechanical ventilation with heat recovery; thereby, they are most the expensive and comparable in cost with package 8. In all cases, package 9 is cheaper and more energy efficient than package 10.