Advice for all electric flat for Dad

Jonesya

In principle E10 is a good idea, those off-peak blocks are timed for the lowest cost periods of the day and should be cheaper than any flat rate tariff because wholesale energy costs and other costs for those off-peak times are lower.

That's the principle, but in practice because the tariff is rare, with few suppliers offering, difficulty in comparing and switching, combined with somewhat complicated metering it's often uncompetitive as there's limited numbers of suppliers competing. The product is good but it's failed by a broken market for time of use tariffs.