ᐅ Optimal Temperature for a 300-Liter Hot Water Storage Tank?

Hello,

We have a 300-liter (79-gallon) hot water tank and a gas heating system. The factory setting is 60 degrees Celsius (140°F), but our heating technician suggested that 50 degrees Celsius (122°F) would be sufficient. What about legionella bacteria? We certainly won’t completely empty the hot water tank (which supplies two showers). Our bathtub holds 220 liters (58 gallons), but it is used only occasionally. Is a temperature of 50 degrees Celsius (122°F) enough? What temperature do you keep in your hot water tanks?

Best regards,
Sabine

Same setup for us, but with 2+2 people. We set it to 50 degrees Celsius (122 degrees Fahrenheit).

We are also 4 people, and our shower heads deliver 9 liters per minute (2.4 gallons per minute).

Best regards,
Sabine

It also depends a bit on whether you have a lawyer-style shower or not. Large rain showers quickly drain the water heater.
Otherwise, we also use 50 degrees Celsius (122°F). If I know I want to take a bath in the evening (I like to cook for myself), I set it to 55 degrees Celsius (131°F) about 2 hours beforehand.

48 degrees Celsius (118 degrees Fahrenheit) is enough for us.
But there are only two of us.

I’ll add a question: How often is the domestic hot water heated daily at your place?

Our heat pump provides supplementary heating when necessary. Without usage, it may turn on about three times a day; otherwise, it mostly runs after higher consumption activities such as bathing, showering, etc.