What should the temperature be of the hot water coming out of my tap be?

[Mottie]

Just having a piddle around with my shower that seems a tad on the cold side lately. The hot water coming out of the tap feels 'hot' to me on its own but I’ve just measured the temperature with a thermometer and it is showing 48°. Should it be hotter? Any hotter and I think it would be scolding. I’ve cranked it up 5° on the tank thermostat and I’ll check it again when it’s up to temperature.

I understand it should be 60° to kill off any bacteria but why are hot water cylinder thermostats fitted at the bottom of the cylinder - surely if I set it to 60° on the thermostat at the bottom of the cylinder it’ll be a lot hotter than that at the top where it is drawn from, won't it?

 

[tincup]

60c though this could be too hot for children.

 

[Murdochcat]

55 degrees at the tank = less at the shower , so not a problem.

 

[Harry Bloomfield]

The recommendation, is to increase the cylinder temperature upto 60C, once per week, to kill off any Legionella in the system. My control allows for my system to do that automatically once per week, but I maintain my cylinder at a precise 60C[1] throughout the week, whenever the cylinder is set to be on. I do like the hot water at my taps to be 'properly hot'.

Properly hot, makes washing up easier, and you don't need as much hot mixed in with the cold, for a bath, so you have some hot left in the cylinder. The downside, is the risk of scalding, if you have kids and elderly in the house. A way around that is thermostatic mixer valves, mixing the cold with the hot, before it comes out of the tap. I added one to the downstairs toilet washbasin, when the kids were young, and did away with the cold tap completely. Hot water comes out of that, at a comfortably warm temperature, for handwashing.

Stats should measure the temperature about 1/3rd up from the bottom. Heat rises, so if it were at the top, only the top would be heated. You don't want it too low, because that's where the cold comes in, and that is never heated at the bottom.

[1] My system uses a thermistor sensing the cylinder temperature, which is much more accurate and responsive than the usual bi-metal cylinder stat.

 

[Exedon]

If you have a pressurised cylinder esi make a electronic dual stat that automatically boosts water over 60c once a week.