Thanks for that, That would tie in with the off and on periods I observed. I have no problem with that because nothing would be running between 12.30 and 2.30am (apart from fridge and freezer), as long as those on/off times are fixed, and not variable as someone has suggested.

We don`t have a time switch so there is nothing to be adjusted, or to go out of adjustment. The low rate switching is controlled by a radio teleswitch which is activated by a radio signal. Someone said on another forum that the 10.30pm start is probably to put some heat into the rooms before bedtime, and the 7.30am finish to do the same around breakfast time,but if that`s the case they should make it clear that there is a 2 hour period during the night when peak rate power could be being used.

Our supply is definately Economy 7. I checked the on and off times last night and this morning. The supply switches over to night rate at 10.30pm and then back to day rate at 7.30am. so that`s nine hours, and as we only get seven hours low rate per night, for two hours each night the supply is running on day(or peak) rate.

Our supplier is Southern Electric, and last week I bought a home energy monitor. As we have an Economy 7 suppy I need to know the times when the supply switches from normal rate to low rate, and back to normal rate again. The way I did this was to change a flex outlet feeding one of our storage heaters, to a 13 amp socket, temporarily disconnecting the storage heater (the heaters are off anyway, havn`t used them since early June). I then plugged a table lamp into the socket then sat and waited. As I expected, the low rate started at 10.30pm, and I thought it would stay on low rate till 5.30am. But that is not the case. Although I didn`t sit up all night I found the following: It was still on low rate at 11.15 pm It was on normal (or peak rate) at 1.15 am It was on normal (or peak rate ) at 2.00 am It was on low rate at 3am, 4am, 5am, and 6.15am. This means that anyone with an Economy 7 water heating controller may be paying peak rate for at least part of the night while the immersion heater is in use. I have already reset our immersion heater controller to operate between 3am and 6am, but the point is that this sounds like a [problem]. How much over the odds have we been paying for heating our water at peak rate, when we thought we were using the Economy 7 tarrif? And how many users are aware that the night rate is not 7 continuous hours of cheap electricity? It seems that Southern Electric switch the night rate on so we can see that our storage heaters are warming up before we go to bed, and then get up to all sorts of tricks once we are asleep! I realise that the storage heaters only work on the night rate because they are switched on by the radio teleswitch, but we are being charged peak rate for anything else used , for at least part of the night (supposedly Economy 7 period). Is anyone else aware of this? I would welcome any comments.