Gas Hot Water System

Early July we demolished the old aircon in our unit and put in the plastic box for the new gas hot water system. And it actually took 3 and a half months for the gas hot water system to be actually installed!! The plumbers came in yesterday and ran and connected all the water and gas pipes.
[... and I can't stand Italian looking plumbers calling me 'Darling' or 'Love'!!!]
Anyway, we know have a nice remote which allows us to dial the exact temperature. And now that we know the exact temperature of the water we started arguing already whether 40C or 41C is the best temperature to have a shower ;-)