Hot water - on all the time or timed?

Morn

Just wondering if anyone has figured out whether it is more economical to keep the HW on constantly or whether there is benefit in having it come on and off throughout the day?

I think that the cheeper method is to keep it on all the time because the tank is insulated and thus i designed to keep the water as hot as possible. If the temp drops a little then the boiler will come on for a short time and bump it back to the set level and go off again.

If it's on then off etc... the water gets a lot colder during the off period so when the boiler comes on again and it has to use more energy to reheat previously hot water back to its previous temperature.

That's enough of my ramblings, anyone got an opinion?

Morn

Cardew

This has been covered dozens of times and your reasoning is incorrect.

just 2 examples:

Firstly if you go away for a year would you leave the Hot Water on constantly? How about a month? A week? A day? A few Hours? - all exactly the same principle.

Secondly if your theory is correct, why not leave your kettle simmering all day; again exactly the same principle.

There is absolutely no doubt that the longer your HW heating is off(and Central heating as well) the more you save.

That said with a well insulated tank the difference between leaving the water on 24/7 and timed is not huge. On average a tank full of hot water will lose around 3kWh a day; and that heat is not lost as it goes to heat up the house.

VfM4meplse

Agree with Cardew.

With an efficient boiler, 40mins twice a day will provide a 4 person family with more than adequate hw.

Morn

I stand corrected, thanks for the comments!!