Hi. I’ve just found this site and forum. Much needed, I think, as the E10 tariff can be so confusing, and in my mother’s case, a nightmare as she’s seen her monthly payments go up from £90 a month to over £200 a month without any change in use. She did get a replacement storage heater from Creda which, as far as I can see, is configured for the E10 times, and is wired with two separate supplies (heat and normal). I suspect that somehow, it’s still using peak rate electricity, but oddly, the peak rate usage was high in the summer even though the heaters were switched off. Monitoring what’s going on is tricky as the meter is mounted too high for my mother to read it, and as it’s an old, 3 rate meter, it only reads in whole kWh, and has no way to see the current kW usage. Many of the people in neighbouring flats have changed to E7 and report much lower bills, but in theory, E10 should be cheaper, and also, to go over to E7, she’d need to have timer switches added to the storage heaters that are currently wired directly into the Heat circuit.
I’m sure E10 can still be cheapest, when everything works correctly, but her experience is that when bills suddenly go through the roof, it can be very difficult to work out why.