A 16 kW solar system: cost and output
At sixteen kilowatts you are no longer sizing to a household. You are sizing to a roof and to a daytime load — and if there is no daytime load, you are building an export business at whatever rate you can secure.
| Roughly how many panels | 38 at 430 W |
|---|---|
| Published size band | 10-50 kW |
| Installed cost, median | £19,262 (£1,204/kW) |
| Installed cost, mean | £20,269 (£1,267/kW) |
| Generation, south-facing at 35° | 13,696 kWh a year for a median location; 11,072 to 16,672 kWh across our 25 reference locations |
Cost: Solar photovoltaic (PV) cost data, Department for Energy Security and Net Zero, 2025/26, Total Installed Capacity basis, OGL v3.0. Generation: our own PVGIS modelling at 20% system losses — see generation by region. Panel count is illustrative and depends on the modules quoted.
| Self-consumption | Used at home | Exported | At 12.0p export | At 4.1p export |
|---|---|---|---|---|
| 14% | 1,917 kWh | 11,779 kWh | £1,914 | £984 |
| 19% | 2,602 kWh | 11,094 kWh | £2,011 | £1,134 |
| 23% | 3,150 kWh | 10,546 kWh | £2,088 | £1,255 |
Self-consumption rates are MCS guidance note MGD 003's figures for a household using 2,500–2,999 kWh a year — 14% out all day, 19% in half the day, 23% home all day. They are averages for similar households, not a prediction for yours, and self-consumption falls as the array gets larger. Import is the price cap unit rate for 1 July to 30 September 2026. The two export columns are the best and the median open untied rate in our SEG table — the gap between them is what choosing an export tariff is worth, and it is larger than most people expect.
Who this size suits
- agricultural buildings and workshops
- small commercial premises with steady daytime demand
- large rural properties with substantial outbuilding roof area
Roughly 38 panels at 430 W, needing about 76 m² of roof. Higher-rated modules need fewer panels for the same capacity, which matters on a tight roof.
Match generation to daytime load
The single question at this size: what is running while the sun is up?
Refrigeration, workshop machinery, milking parlours, offices, and EV charging all consume during generation hours, and every unit consumed on site avoids a purchased unit. Where a site has that load, a large array is straightforwardly good economics.
Where it does not, the output is exported, and export rates are a fraction of import rates. That is the whole calculation.
What to establish before design
The export arrangement. At this scale, do not assume a domestic SEG tariff is the route.
The connection. A G99 application is required, and the local network’s capacity is a real constraint rather than a formality.
The supply arrangement. Three-phase is effectively assumed at this size.
The roof. Structure, covering age, and access all matter more when the array is large. See structural surveys.
The VAT and tax position, which differs for business use and is a question for an accountant rather than for us.
Check the quote, not the brochure
Divide the quoted price by the array’s kWp and compare it with the published benchmark. Then check what the quote includes, and what it does not — the costs outside the headline are where budgets break.
Sources
- Solar photovoltaic (PV) cost data Release 2025-26, published 28 May 2026, Total Installed Capacity basis. Derived by the department from the MCS Installation Database.
- MGD 003: Solar PV Self-Consumption, issue 2.0 (1 April 2022) Read locally. MCS restricts reproduction, so we cite clauses and quote sparingly.
- Energy price cap unit rates and standing charges
Contains public sector information licensed under the Open Government Licence v3.0.
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