Put simply; because the amount of energy you use every month changes
1. If you are on a Variable Direct Debit: the amount you pay will change each month because you are paying for the amount of energy you use during that period. It is a good way to make sure you don’t build up a debit or credit on your account
2. If you pay by Fixed Direct Debit: the amount you pay may change throughout the year because whilst we can tell you how much every unit of energy costs, we cannot tell you how many units you will use. That all depends on your appliances and consumption in your home.
We carry out a review of how much you are paying every 3 months and if it looks like you consumption does not match your Fixed Direct Debit amount (i.e. you are paying too much or too little) we will let you know and adjust your Direct Debit amount accordingly.
You will tend to use more energy in the winter and less in the summer.