The best way to avoid surplus credit and trying to make decisions about whether you should claim back credit, is by keeping up to date with submitting your meter readings.
We advise submitting every 6 months at a minimum, however if you feel that your energy usage has changed it isn't a bad idea to submit more regularly. That way you can avoid a surprise on your next bill.
Usage might change for a variety of reasons; potentially you have more people staying with you and using the showers, or you've got a fancy new appliance, or you are going on holiday for a long period of time.
To submit meter readings you can simply use your Switchd dashboard. This way our systems are also kept to date and we can let you know in advance if anything looks wrong!