Why doesn’t my monitoring device match my utility bill?
Your utility’s billing period may not start on the first day of the month, so be careful when looking at monthly production or consumption to ensure that you’re comparing the same time period.
The measurements from your monitoring device may not record the exact same totals as the utility meter, as the devices use different methodologies to measure the current. It is normal for there to be a difference within a range of +2.5% to -2.5%, and the meter collects the more accurate reading.
Another important difference for both production and consumption is that the utility can only measure what passes through its meter. If your utility offers net metering or similar buyback options, the utility will only credit you for excess generation that passes through its meter back to the grid. In other words, if your home uses electricity generated by your solar panels, this electricity will not show up on your utility bill.
Similarly, your utility will only report on energy delivered through its meter to your home. The utility will debit you for the energy you consume from the grid when your energy needs exceed your solar generation (or at night). If you have consumption monitoring installed, your consumption data will be higher than what the utility reports because your solar monitor is reporting all your consumption whether it came from the grid or from your solar array.
If the values are wildly different from each other and cannot be explained by the scenarios above, you may be experiencing one of the following issues:
- Incorrect configuration of the solar monitor
- Solar monitor calibration issue
- Utility meter calibration issue
If you have questions or are concerned about your monitoring, please contact our Service Department.