How much does a 6 kW solar system cost in the UK?

The table on this page is generated from the official DESNZ cost statistics, which report what MCS-certified installations actually cost per kW. Multiply the median for the relevant size band by 6 to get the median installed price. Your quote will differ with access, roof type and electrical work.

How much electricity does a 6 kW system generate?

On our own PVGIS modelling, at 35 degrees facing south with 20% system losses, the figures on this page give the median across our 25 UK reference locations and the range from the least to the most favourable. A north-facing or shaded roof produces materially less.

How many panels is 6 kW?

About 14 panels at 430 W each, needing roughly 28 square metres of roof. Panel ratings vary, so a higher-rated module means fewer panels for the same capacity.

Is a 6 kW system right for me?

Where a domestic system starts being sized for the future rather than for today's bill. The section below sets out who this size suits. The deciding factor is usually not the roof but how much of the generation you can use as it is produced.

What will I actually save?

It depends on self-consumption and on your export rate, which is why the value table on this page shows three self-consumption rates and two export rates rather than a single figure. A saving quoted without those assumptions is not a calculation.

A 6 kW solar system: cost and output

Six kilowatts is more than most households can use as it is generated. That makes it a system you buy for what you are going to do — a battery, an electric vehicle, a heat pump — rather than for the bill you have now.

Where a domestic system starts being sized for the future rather than for today’s bill.

6 kWp: what the data says
Roughly how many panels	14 at 430 W
Published size band	4-10 kW
Installed cost, median	£9,275 (£1,546/kW)
Installed cost, mean	£9,731 (£1,622/kW)
Generation, south-facing at 35°	5,136 kWh a year for a median location; 4,152 to 6,252 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.

What 5,136 kWh is worth a year, at 26.11p import
Self-consumption	Used at home	Exported	At 12.0p export	At 4.1p export
14%	719 kWh	4,417 kWh	£718	£369
19%	976 kWh	4,160 kWh	£754	£425
23%	1,181 kWh	3,955 kWh	£783	£471

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

detached houses with a large unobstructed roof plane
households with an EV, a heat pump or storage either fitted or planned
anyone with high daytime consumption — home working, home business

Roughly 14 panels at 430 W, needing about 28 m² of roof. Higher-rated modules need fewer panels for the same capacity, which matters on a tight roof.

The surplus question

At roughly 5,100 kWh a year on a median location, a 6 kWp array generates more than the annual consumption of many UK households — and far more than most can use at the moment of generation.

So the honest framing is: most of a 6 kWp array’s output will be exported unless something absorbs it. Whether that is a good deal depends entirely on your export tariff, and the spread between the best and the median rate is wide enough to change the answer on its own.

What makes 6 kW pay

Storage. MGD 003’s tables show self-consumption rising materially with usable battery capacity, and it is the most direct way to convert surplus into avoided import.

An electric vehicle, particularly if it can charge during daylight.

A heat pump. Note that MGD 003 excludes non-typical loads including heat pumps, EVs and electric water heating from its self-consumption method, and says so — meaning its figures are likely to be conservative for a household with those loads, though the guidance does not say by how much.

Genuinely high daytime demand — someone at home, working, with the appliances running.

Roof and network

Six kilowatts needs a substantial single plane or a split across two, which brings a second set of rails and often optimisers. And at this capacity the inverter is well above the G98 threshold unless deliberately limited, so expect a G99 application and the possibility of export limitation.

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 Department for Energy Security and Net Zero · Accessed 20 August 2026 · OGL v3.0 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) MCS · Accessed 17 August 2026 Read locally. MCS restricts reproduction, so we cite clauses and quote sparingly.
Energy price cap unit rates and standing charges Ofgem · Accessed 17 August 2026 · OGL v3.0

Contains public sector information licensed under the Open Government Licence v3.0.

Last verified: 20 August 2026 How we research this Suggest a correction

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