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What do plug-in kits really make?

Output reported by owners, checked by hand, next to what our PVGIS estimate says the same kit should make in the same place, direction and dates.

published owner reports: 0
a year, our estimate for an 890 Wp kit facing south in Birmingham: 853 kWh

Photo: CHUTTERSNAP / Unsplash

No owner reports are published yet. Until there are some, the estimate model below is all we can show. Own a kit? Report what it made: we need at least 5 more before this page means much.

No published reports yet.

Be the first: it takes two minutes and helps the next buyer. Report your kit’s output.

The estimate model

What we expect a kit to make

Every report is compared with this model, worked out for its own place, direction, tilt and dates. Here it is for an 890 Wp kit (800 W inverter) in Birmingham, over an average year, with no shading.

Facing	Garden stand, 30°	Flat or shed roof, 15°	Railing, fence or wall, 90°
South	853 kWh	803 kWh	630 kWh
South-east	811 kWh	779 kWh	587 kWh
South-west	801 kWh	773 kWh	572 kWh
East	697 kWh	712 kWh	440 kWh
West	683 kWh	703 kWh	427 kWh
North	501 kWh	605 kWh	179 kWh

Yearly AC output after the 800 W cap, from PVGIS 5.3 long-term monthly data with 14% system losses. See how we estimate yield, or get figures for your own set-up in the calculator.

Reading the reports

Comparing like with like

Each estimate is for that report. Same kit (its panel power and inverter), the reporter’s postcode district, direction, tilt and exact dates.
Weather moves short periods most. One sunny or dull month can be 20–30% off the average. A whole year is the fairest test.
Shade isn’t in the estimate. A report well below it usually means trees, buildings or a balcony above. Our shade planner estimates that loss.
Only checked reports appear. We approve each one by hand and leave out any that fail the same checks as the form.

Add yours

Own a kit? Share what it made

You need the kWh your kit generated between two dates, usually from the inverter’s app. It takes two minutes, and we only keep your postcode district.

Report your yield

Real-world yields: questions

How much do plug-in solar kits really generate?

We don’t have enough owner reports yet to say (0 published so far). Our PVGIS-based estimate for an 890 Wp kit facing south on a 30° stand in Birmingham is about 853 kWh a year; owner reports will show how real kits compare.

Where do these reports come from?

Owners send them through our report form: the kWh their kit generated between two dates, its postcode district, direction, tilt and mounting. We check every report by hand before it appears, and reject impossible figures or dates.

How is the estimate worked out?

From PVGIS 5.3, the European Commission’s solar data service: long-term average monthly output for the report’s postcode district, direction and tilt, with 14% system losses, capped at the kit’s inverter output. We spread each month evenly over its days to match the report’s dates. It assumes no shading and an average year of weather.

Why might a kit make less than the estimate?

Shade from trees, buildings or a balcony above; a dull spell of weather; the inverter off for a while; or the direction and tilt differing from what was entered. Short periods swing the most. A report a few per cent above the estimate is often just a sunny month.

Sources

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