Thank you for the question. Yes, the electricity savings values that are output by the InVEST Urban Cooling model are based on the forgone cost of A/C (electricity) that would otherwise have been used to cool the buildings if not for the presence of nearby natural areas and green spaces. As stated in the Appendix of the User Guide, “If A/C prevalence is low, this valuation metric should not be used as it assumes that energy costs will increase with higher temperatures (and higher A/C use)”. There would not be electricity cost savings if there was no A/C in the buildings.
So, while you are correct that the electricity cost savings output is not appropriate for a city like Munich that does not use A/C, the model also provides an estimate of work productivity savings (as a %) that you may find useful. However, changes in productivity are only predicted when the Wet Bulb Global Temperature reaches or exceeds 27.5C, which I imagine is unlikely for Munich.
Still, the model’s other results may be of interest to you, namely the cooling capacity index, heat mitigation index, average temperature estimates, and average temperature anomaly.