wrote in message
oups.com...
flash wrote:

I would be interested in some figures on this sort of thing as I am
trying
to work out whether it is cheaper to heat my water overnight using oil or
economy 7.

With E7 you often pay a bit more during
day rate, which can cancel out
the saving. With E7 you're heating the
water many hours before its wanted, so use
more energy to compensate for cooling later on.

E7 is not generally competitive.

It can be using a large thermal store that serves enough for all day, low
temp underfloor heating and a heavy insulation and making the house
air-tight.