"Dave Plowman (News)" wrote:

In article ,
riccip wrote:
Normally you would only use the electrical immersion heater to
boost the water heating early in the morning or before filling a
bath.

It's a poor boiler that would need this.

It's reasonable to assume a flat would have a small boiler,
otherwise it depends on the household demand for hot water. On
cold winter mornings any boiler is best left to heat the house
ASAP if "Economy 7" electricity (or it's equivalent) is
available.

It's expensive to use unless you have cheaper night-time
electricity, in which case you'd set the timer to heat it at
night.

Also during the summer when you don't use your CH it can
be cheaper to turn the boiler off and just heat the water by
electricity.

Again, it would be a very inefficient gas boiler/system where full price
electricity would be cheaper. And running the boiler every day for hot
water keeps the pump in good fettle.

Which is why I said "cheaper night-time electricity". However in
the summer there is no more expensive way to heat water than
leaving a conventional boiler cycling over the HW system alone,
unless you mean combi-boilers?

riccip