Turn off Hot Water Tank to save money?

Chrysalis

[Deleted User] said:

Legionella is a very small risk in this country

Arguably, so is Scarlet Fever which is in the news at the moment. I would say that it is a given that if people stop heating their hot water cylinders there will be an increase in Legionella infections. The risk is magnified if there is very little water flow.

Maybe but I expect for many been able to afford their billis more important than things like that.

I know I am personally at the point that I think turning the heating on purely for pipe maintenance is out of the question.

Jami74

We have a large water boiler and for years it was on 24/7 and I'd only turn it off if we went on holiday. Then about 3 years ago I put it on a timer, 2 hours overnight on the E7 and an hour in the afternoon and it instantly saved us money. Unfortunately the timer broke at the beginning of this year so we've just been turning it on and off manually a couple of times a week to run overnight for next day baths. I would never go back to heating that large tank of water 24/7 again. We have an electric shower.  

sparky0138

k_man said:

How big is your tank, and how well insulated is it?
And do you know what the tank temperature is set to?
How much hot water do you use to wash up?

The losses from the tank (if full) are 1 - 2kWh per day if well insulated, and the losses from the heating system getting up to temp to heat the water, could be another 1 - 2kWh per instance of heating.

So you may find you can heat the water once every 3 or 4 days to 60°C for 40 mins (for the legionella cycle), and still have hot (enough) water all week for washing up.

Not sure about the tank size but it's set to 60 degrees and in my opinion it's well insulated. We really don't use much hot water to wash up, maybe half a small bowl each time before having to add some cold to make it bearable. Will have to do some tests and maybe try every other day.

Lorian

The how many days or how long it comes on are all over ridden by your tank stat being set to 60c of course so even if you set it to come on for 2 hours each day it will still turn off sooner once the tank stat reachs temp.

 The lower the tank temperature the slower the heat loss. Throwing a much insulation at it as you can all helps and on the surrounding pipes  I have a traditional  foamed tank with two extra red jackets and the pipes have thick lagging. This massively reduces the losses.

One other thing about heating it - as it's a 20 year old tank coil through it for the hot water to flow cannot have many turns so my ,boiler modulates down to about 6kw when beating the tank only - which is kind of ok as with a lowish flow it keeps the return below 55c and hence the boiler condensing.