Isn't that what I wrote?Ignoring interim losses, you can't anyway. A heater which stores XkWh will store that much whether you fill it up over 14 hours or 7.It means you don't get to use any more cheap electricity in the fourteen hours than you would in seven.
XkWh in T hours = XkWh in 2T hours.
I did mean it as a benefit to the supplier; not the consumer.
Do your interim losses include 'letting it all out' ?
Why do they normally only give you seven hours, then?
Apart from that, I thought they only let you have a cheaper rate during the night because demand was low.