*2.3. Combined Building Envelope Retrofitting and System Upgrading*

Finally, the effects of a combination of the building envelope retrofitting and of the system upgrading were simulated. Specifically, the energy retrofitting of the whole envelope was considered, together with the new technological systems, as reported in Table 3. Five combined scenarios were built. Considering the most frequent system layouts of the surveyed dwellings, scenarios #11 and #12 can be considered representative of a typical intervention carried out on a dwelling with centralized heating system. DHW production by means of a micro-heat pump is scenario #13 representing when there is no opportunity to upgrade the space heating system. On the contrary, scenarios #14 and #15 can be considered representative of comprehensive intervention carried out on a dwelling with an independent heating system.

**Table 3.** Combination of building envelope retrofitting and system upgrading.

