Lower the hot water temperature in the single-family house

Hello, in many topics here it is mentioned that one can save energy by lowering the hot water temperature, since in a single-family house there is actually no danger from legionella. Now the question is, is this scientifically proven? My wife is really worried about this and would like to have well-founded expert knowledge. We have a 300L hot water storage tank, three faucets that are all used daily, and we also shower daily. Cooling down the hot water seems to me to be economic madness and I want to set the temperature so low that when showering at the hottest setting, only the heated water is used directly and not mixed. Is this really possible without risk? Our old gas heating system does not have a legionella program. Thank you for your evidence-based statements.

I think the same as you... first warming up, then mixing, also sounds illogical to me. But I can't contribute anything scientific either.. ;)

My landlord turns the hot water storage up to 60° for 1 day every 2 weeks here in the 5-unit rental building and then switches it back. The heating system is already about 12 - 13 years old. I suspect it could also be programmed, but he is currently not dealing with that. Instead, he has scheduled the biweekly heating increase in his calendar.

So if your heating system does not yet offer a legionella program, you basically have to do it manually. But that should be easily possible.

Legionella bacteria develop (almost) only in standing water. If you regularly shower in a single-family house, the hot water in the tank is circulated and renewed quite frequently. So there is no danger here. Furthermore, Legionella are inhaled through the respiratory tract. The danger therefore exists ONLY when showering (spray mist) and not when drinking it. You can therefore safely lower the hot water to 45°C. Edit: Normally, shower water is between 30-38°C.

The maintenance company of the heat pump lowered the temperature from 50 to 45 degrees in April to save energy.

One can therefore safely lower the hot water to 45°C.

Thank you for the answer. However, reliable sources would be helpful here to convince the rest of the family as well.