Fixed tarrif

Your DD keeps increasing? DD amounts are usually reviewed once a quarter; if you’re on a Simpler Energy plan, the rates have for several years increased once a quarter, so it’s natural for the DD to have to rise as well. Are you seeing DD increases more often than once a quarter?

You say you have a sizeable credit balance. OVO’s billing system updates your account every day, so it makes a lot of difference when you note the balance. It will be lowest the day before your DD is taken and highest the following day. 

The DD has in the past been calculated from just a few numbers: the Future Annual Consumption figures, the unit rates and standing charges shown on your account’s Plan page, and the current balance. When the Direct Debit calculator is working properly, you can get a good idea of how healthy your account is.

Fixed-rate plans nowadays are no cheaper than variable ones, and in fact there is most likely a premium to be paid. That probably means the DD will have to increase, of course. Switching tariff won’t make any difference to the amount of refund you can get.