Check a billSmart meter overcharging after the clocks change? Check the tariff window before you complain
Clock-change issues are most important when your tariff depends on time, such as Economy 7, off-peak windows or multi-rate smart meter billing. The goal is to check whether usage has been allocated to the wrong register or period.
Use with
What to check first
Tariff type
Check if you are single-rate, Economy 7, EV, off-peak or another time-of-use tariff.
Register mapping
Look for rate 1/rate 2, day/night or peak/off-peak usage and whether they look swapped.
Clock change date
Compare usage before and after the clock change, not just the total bill.
Supplier explanation
Ask how they allocated usage across time windows.
Supplier request wording
Please check whether my smart meter and tariff registers were applied correctly after the clock change. I am concerned that peak/off-peak usage may have been allocated incorrectly. Please confirm the tariff window, register mapping and whether the bill needs to be corrected.
Next checks
Frequently asked questions
Does every clock change affect smart meter bills?
No. It matters most when billing depends on time windows or separate registers.
What is the strongest evidence?
Bill breakdown, tariff schedule, register readings and messages showing how the supplier mapped the usage.
Should I ask for a refund immediately?
First ask the supplier to confirm whether the allocation is correct and to rebill if it is wrong.