Q: Heat pump hot water heaters and bacteria.

I tried to ask this tonight, but in addition to the hot water radiator situation, for Heat Pump Hot Water Heating (for your potable hot water), what temperature can those heat pumps keep your water at? If it can’t keep it above 120 continously, that would be a huge health hazard: “Water conditions that tend to promote the growth of Legionella include: temperatures between 20° and 50°C (68° – 122°F) (The optimal growth range is 35° – 46°C [95° – 115°F])” from OSHA

A: My HPHWT keeps the water at 140F which is hot enough to kill bugs. This is hot enough to scald skin so the 140F water is mixed with cold water at the valve to bring it down to a safe 125F. I have had no problems with this.