Water Heater

If you have the amps  (which you will have if on a CC site) just leave it on.

Agreed. Leave it on. It's thermostatically controlled so will switch itself off when up to temperature and you'll then not need to heat the whole thing from cold.

If, on the other hand, you are on a metered supply and paying for what you use .... then turn it off !   Keeping a tank of water hot unnecessarily will always use more power than just heating it when you need it, even if it does cool down somewhat in between.

Personally, even if unlimited electric is included in the site fee, I would still turn it off simply because I hate waste.  Ultimately the overall cost of electricity will be reflected somehow in the fees.

On present van with Alde heating the heating is set to 'ON'. Although pump and radiators are not operating the boiler keeps water hot. On last van with electric immersion I generally left it on on site purely because switch was in the airing cupboard and not immediately to hand.

I disagree that turning it off will save electric. Letting the thermostat do its job means it will only use a little power every now and then to bring it up to temperature. Turning it off means using a lot of power to heat from cold.

Maybe depends how often and how much hot water you intend to use. We normally only use it for washing up in the van, turn it on for 20 minutes or so before we need it and then off. Agree with TW though, there's probably not an awful lot of power saving given the limited volume of water involved.

There you go, Gatewaya89, just do what suits you best 👍🏻

Put ours on when we arrive on site then turn it off when we leave. If on hard standing I drain it down before we leave. If not I drain it when we get back to the storage site. 

I agree that keep turning it on and off is less economical than just letting the thermostat do it's job plus you always have hot water to wash your hands with.

fully correct. I could show you the maths/physics but heating 1kg of water by 1 degree C requires 4185 Joules of energy (supplied by electricity or gas).

So using a thermostat means you only have to heat the water by a few degrees every so often and is less wasteful than the same amount heated from cold. 

no, see above answer a thermostat will mean it only uses electricity when needed not all the time