EDF do several tariffs with very low off-peak rates. I"m on the Blue+ price freeze 2 years and paying 5.4p off peak. But most EDF tariffs have a very high peak tariff so it only works if you use a lot of off peak and not much peak electricity. With an electric car and immersion heaters I use 3 times as much off- peak as peak at my tariff is nearly the cheapest, beaten only by another EDF tariff which wasn't fixed for 2 years. It should be even better now I've had a powerful 2 installed and hope to use very little peak rate electricity. The Easy online fixed 18 month is only 4.5p off peak which is even better, much less then their EV tariff, but nearly 25p peak. It all depends on your usage balance.