Legionella - 45c Safe or Not?

Hardware Heatpump
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I feel like this would be one talked about a bit but I can’t find much here about it. 108 / 406 (~27%) people on heatpumpmonitor.org have both the following:

  • Their Legionella cycles disabled or never
  • Their DHW set to 50c or less

50c was chosen because apparently from that temperature the bacteria start to die.

Currently I am set at 45c with Legionella cycles disabled, I’ve read (and watched) the Legionella article from Heat Geek which states that if you use your hot water tank up frequently (we do) then you are at a very reduced or nonexistent risk.

Does anyone have any good sources of information which discuss the risks associated with storing water at a low temperature? Would rather keep it factual than opinion based if possible.

If there is already a good thread discussing this please feel free to point me at it, I couldn’t find anything generic about how safe low water temp storage is using the search, just general info about manufacturer-specific legislation cycle directions.

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I looked into this recently too after an discussion with someone on reddit. I don’t run a Legionella cycle and store at 45 degrees. We cycle through our store volume every day or two.
Anecdotally, all I can say is that I’m still alive and well, and fairly sure I don’t have Legionnaires, but that’s all I can say.

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I used this chart from heatgeeks to make my decision, what i liked was the inclusion of % water turn over.

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