## 4 Conclusions  
In order to safeguard artifacts housed in historic buildings from the effects that climate change will have on the indoor climate of these types of buildings, several passive retrofit measures were tested in this study. To achieve this goal, the following tools were used: (1) a calibrated whole-building hygothermal model of a high thermal inertia building; (2) future weather files: RCP 4.5 and RCP 8.5; and (3) decay assessment models: biological, chemical, and mechanical. Moreover, to determine how the mitigation potential of the retrofit measures would vary in accordance with the location, two different types of climates were tested: a Mediterranean climate (Seville, Spain) and a humid continental climate (Oslo, \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Number of Simulations** & & **1350** \\ \hline \multirow{3}{*}{Step 1} & Simulation setup & Manually & 23 h \\  & duration & MATLAB & 3 min \\  & & Time savings & 99.8\% \\ \hline \multirow{3}{*}{Step 2} & \multirow{3}{*}{Simulation run time} & PC\#1 & 1485 h \\  & & 20 PC\#2 & 567 h \\  & & Time savings & 61.8\% \\ \hline \multirow{3}{*}{Step 3} & Data assessment & Excel & 34 h \\  & duration & MATLAB & 17 h \\ \cline{1-1} \cline{3-3}  & & Time savings & 51.1\% \\ \hline \multirow{3}{*}{Overall duration} & Traditional & 1542 h \\ \cline{1-1}  & & New & 584 h \\ \cline{1-1}  & & Time savings & 62\% \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Time savings achieved using the developed methodology for the examples presented in Section 3.2. Norway). In addition, insulation layer thicknesses range for the tested wall assemblies and ceilings/roofs are also recommended. Lastly, the benefits of the therein methodology that aims to reduce the overall simulation time of whole-building hygothermal studies are also presented in terms of time savings. Overall, it was visible that the retrofit measures can mitigate, to a certain extent, the effects that climate change will have in terms of the increase in the risk of mechanical, biological, and chemical decay. It was also shown that the passive retrofit potential would vary in accordance with the climate. In addition, it is the authors' belief that their mitigation potential can even be heightened if they are properly combined (e.g., using multi-objective optimization). In accordance with the building type and use, but also the constitution of the building assemblies and ventilation rates, the outdoor climate, and eventually the climate change, can have a very significant influence on the indoor climate and, consequently, on the preservation of historical artifacts. In contrast, if the artifacts are kept in more recent buildings, which were built for the purpose of safekeeping artifacts and, due to today's regulations in the construction sector, are more airtight, then the artifacts will be less prone to the attacks caused by the outdoor climate. Finally, it is safe to assume that the influence of the outdoor climate on the preservation metrics is largely dependent on the building specifications. The tested retrofit measures reduce the increased risk of biological decay caused by climate change in Seville and Oslo, especially for RCP 8.5 in the far future. For example, the mold risk factor (MRF) decreases considerably and leaves the risk region for the preservation of the artifacts (i.e., values higher than 1.0) for a wall calcium silicate board system thicker than 7.3 cm for Seville and 15.7 cm for Oslo. Climate change is also responsible for an increase in the risk of chemical decay since the equivalent lifetime multiplier (eLM) decreases considerably. For example, the eLM is 0.68 for Seville in the far future for RCP 8.5, i.e., a decrease of 39% when compared with the reference climate value (1.12). However, the tested retrofit measures manage to mitigate this increase to a certain extent. Due to the climate particularities, chemical decay-susceptible artifacts are unaffected by this type of decay in Oslo.