Your solar app says the roof generated 20kWh, but the utility records only 7kWh of export. Those readings can both be correct. Generation, household consumption, battery charging, grid import, and grid export describe different energy flows. Comparing them requires matching the measurement points and the time period before assuming a meter is wrong.
Energy used inside the home may never cross the utility meter
In a simple grid-connected installation without a battery, some solar output can supply household loads directly. Only the surplus crosses the grid connection as export. Conversely, the house can import energy when its demand exceeds solar output. A utility meter at that boundary is not necessarily measuring total roof generation. That is why a sunny day can show substantial generation while export remains modest if appliances use much of the energy locally.
Start with a balance that has clear assumptions
Imagine a simplified battery-free day with 20kWh of AC solar generation, 13kWh consumed directly from solar, and 7kWh exported. Those values balance without any missing energy. If the home also imports 5kWh at other times, total household use would be 18kWh in this example. The calculation ignores small boundary differences and assumes consistent measurements. It illustrates why comparing 20kWh generation with 7kWh export is not an accuracy test: the quantities describe different parts of the balance.
A battery adds both timing and conversion effects
Storage can absorb solar energy now and supply loads later, with losses and reserve constraints along the way. The dashboard may report battery-side DC energy or AC energy at an inverter connection. Those figures cannot always be added directly without checking definitions. A battery that begins and ends the day at different charge levels also changes the balance. Write down where each measurement is taken before trying to reconcile a system that includes storage or multiple inverters.
Matching dates is more complicated than it looks
A billing period may start halfway through a calendar month, while the app defaults to the full month. Time zones, daylight-saving changes, interval boundaries, delayed uploads, and missing communications can also alter displayed totals. Compare exported interval data where available, using the same start and end timestamps. An app screen that has not refreshed is not a fresh meter reading. Check the last update time before treating a small discrepancy as evidence of a wiring or billing fault.
Investigate patterns that the energy balance cannot explain
If consumption appears negative, flows reverse unexpectedly, or differences remain large after the periods and boundaries match, ask the installer to review monitoring configuration and sensor placement. Do not move current sensors or open electrical panels yourself to experiment. Keep screenshots and exported records, including the units and timestamps. The installer can examine monitoring behavior; the utility can explain its meter records and bill calculation. Each party needs evidence relevant to the part of the system it measures.
What to check before you act
- Compare the same dates, time zones, and energy units.
- Separate generation, direct use, import, export, and battery flows.
- Check data freshness and any missing monitoring intervals.
- Escalate unresolved discrepancies with exported records rather than one screenshot.
Common questions
Does low export prove the solar panels are underperforming?
No. Local consumption or battery charging can absorb much of the generated energy before it reaches the grid boundary.
Will exported kilowatt-hours always receive the retail electricity price?
No. Compensation depends on the applicable utility arrangement. Read the current tariff and bill rather than inferring payment from energy alone.
The practical takeaway
Reconcile solar readings as an energy-flow problem first. Once the periods, units, and measurement boundaries match, a difference becomes meaningful evidence instead of an apparent contradiction.
References and further reading
Numerical scenarios are illustrative unless identified otherwise. Follow the exact product instructions; component ratings and local installation requirements can differ.
