What would a 210 kWp array produce in Winchester?

Yes. At 917 kWh per kWp a year, a 210 kWp array on a Winchester roof models at around 193,000 kWh. What changes the answer is how much of that the building uses during opening hours rather than exports. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.

Is planning permission needed for panels on a Winchester office or shop?

Usually not a full application. In England, panels on the roof of a non-domestic building are permitted development under Class J of Part 14 of the General Permitted Development Order, with no capacity cap since December 2023. Above 50 kW, which covers most commercial arrays, you must first apply to Winchester for a determination on prior approval of the design and appearance, in particular glare on neighbouring land. On a flat roof panels may stand no more than 1 metre above the roof and must sit at least 1 metre from its edge, and listed buildings and scheduled monuments are excluded. See our planning permission guide for the detail.

Will rooftop solar improve the EPC rating of a let building in Winchester?

It can. A non-domestic EPC is an asset rating, and on-site generation counts in the calculation, so an array usually lifts the score. Let property in England and Wales must be EPC E or better today. The government's interim response of 18 June 2026 proposes EPC B, where cost effective, from 2031 for let buildings over 1,000 m², and drops the EPC C step once planned for 2027. How far solar moves a particular building depends on its fabric and services, which is why the EPC assessor models it before anything is fitted.

Does the grid around Winchester have capacity for export?

Scottish and Southern Electricity Networks is the distribution network operator for Hampshire. Arrays above 3.68 kW per phase connect under G99, and the application sets the export limit. It is part of the design work we arrange.

Commercial building solar panels in Winchester

Whether solar pays on a Winchester commercial building depends less on the panels than on who owns the roof and who pays the bill. The survey starts with the membrane and the deck: how many years the covering has left, what the roof can carry in ballast, and where plant and its shade rule panels out.

917 kWh per kWp a year at this latitude, so a 210 kWp array models at about 193,000 kWh. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.

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Drawing Winchester commercial roof

Roof 60 x 32 m, 1,920 m²

Array 210 kWp, east-west

Yield 193,000 kWh/yr

Scale 1:400 / Rev A / SO23

Illustrative layout for a flat commercial roof of this size, with plant, shade and access kept clear. Your own figures come from the roof survey.

48,480: people in the Winchester built-up area (ONS Census 2021)
1,380: office properties on the rating list in Winchester (VOA, March 2025)
730: retail properties, 20 of them large-format (VOA, March 2025)
0: named commercial rooftop schemes on the planning record nearby (REPD, Q1 2026)

The commercial edge of a Home Counties town, offices and a retail park with solar on several roofs — Commercial stock of the kind we survey across South East. Generated illustration, not a named site.

Solar PV for commercial property across Hampshire

What a flat roof in Winchester generates

Modelled irradiation here is 1,180 kWh per square metre a year on a low-tilt array, which works out at 917 kWh for every kWp installed (EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss). That is around 3 percent above the mean across the towns we cover.

Commercial stock in Winchester

Winchester has 1,380 office premises and 730 shops and other retail premises on the non-domestic rating list, according to the Valuation Office Agency. By office stock the district sits above the median of the 318 districts in England and Wales; by retail stock it sits in the bottom quarter of the 318 districts in England and Wales.

20 of those retail properties are superstores, large food stores, large shops or retail warehouses, together about 28,000 square metres. Single storey boxes of that size are where most commercial rooftop solar actually gets built, because the roof is big, flat or shallow, and uninterrupted.

The same list carries 290 hotel, leisure and assembly properties in the district. Leisure centres and hotels run seven days a week, which puts weekend generation to use that an office would export.

Source: Valuation Office Agency, Non-domestic rating: business floorspace, 31 March 2025 (published December 2025), counts and floorspace by special category code and local authority district, England and Wales.

The built-up area holds about 48,480 people, so the stock here runs to high street premises, a supermarket or two and the odd hotel (ONS Census 2021 built-up areas).

Surveys run across SO postcodes, SO23 outward.

FIG. 1 What a Winchester roof makes, month by month

Jun produces 5.7 times what Dec does on the same roof. A 210 kWp array here models at about 193,000 kWh across the year, but it arrives unevenly, which is why we size against your summer daytime load and then look at whether storage is worth adding for the shoulder months.

Monthly figures as a table

Month	kWh per kWp	210 kWp array
Jan	26	5,460
Feb	40	8,400
Mar	76	15,960
Apr	107	22,470
May	122	25,620
Jun	126	26,460
Jul	126	26,460
Aug	106	22,260
Sep	83	17,430
Oct	52	10,920
Nov	31	6,510
Dec	22	4,620

Source: EU PVGIS v5.2

FIG. 2 Winchester against the rest of Hampshire

Portsmouth987
Fareham980
Southampton950
Eastleigh942
Winchester917
Andover915
Basingstoke906
Fleet904
Farnborough903

Winchester ranks 5 of 10 towns we cover in Hampshire on modelled yield, against a national mean of 886 kWh per kWp. The county runs from 903 to 987, a spread of 84 kWh per kWp. On a 210 kWp commercial roof that is about 17,640 kWh a year between the strongest and weakest town in the county.

Bars are zero based, so length is proportional to the figure. Where a county is flat, that is the finding: location is not the lever, consumption is. Source: EU PVGIS v5.2, modelled per town

All solar on record near SO23

Every scheme in this postcode district in the government's Renewable Energy Planning Database, Q1 2026, ground and roof mounted, commercial or not. None of them is ours. Together they are a fair guide to how the local network has been treating export applications.

Scheme	Operator	Capacity	Mounting	Status
Micheldever Tyres Winchester, Winnall Warehouse - Solar PV Panels	Micheldever Tyres Winchester	n/a	Roof	Awaiting Construction

Grid connection through Scottish and Southern Electricity Networks

Scottish and Southern Electricity Networks is the network operator here, and their answer on export capacity shapes the design. Any commercial array above 3.68 kW per phase connects under G99 rather than G98, and the application fixes what you are allowed to push back onto the network. If the local network is tight, limiting export rarely breaks the case here: most of the generation is consumed on site while the building is working.

Across Hampshire the planning database records 237 solar schemes totalling 1634 MW, of which 51 are operational (REPD Q1 2026).

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Send us the postcode

Tell us where the building is, roughly how big the roof is, and whether you own it or lease it. We come back with what it can carry, what it would generate against your consumption, and the three ways to pay for it.

Lenzie Consulting Ltd arranges the survey and passes your details to our MCS-certified installation partner so they can quote.

Your name Company Email Phone Site postcode Building type Your interest in the building Roof area Annual electricity spend What are you looking at?

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We pass your details to our MCS-certified installation partner so they can quote. Read the privacy notice.

Questions about solar in Winchester

What would a 210 kWp array produce in Winchester?: Yes. At 917 kWh per kWp a year, a 210 kWp array on a Winchester roof models at around 193,000 kWh. What changes the answer is how much of that the building uses during opening hours rather than exports. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.
Is planning permission needed for panels on a Winchester office or shop?: Usually not a full application. In England, panels on the roof of a non-domestic building are permitted development under Class J of Part 14 of the General Permitted Development Order, with no capacity cap since December 2023. Above 50 kW, which covers most commercial arrays, you must first apply to Winchester for a determination on prior approval of the design and appearance, in particular glare on neighbouring land. On a flat roof panels may stand no more than 1 metre above the roof and must sit at least 1 metre from its edge, and listed buildings and scheduled monuments are excluded. See our planning permission guide for the detail.
Will rooftop solar improve the EPC rating of a let building in Winchester?: It can. A non-domestic EPC is an asset rating, and on-site generation counts in the calculation, so an array usually lifts the score. Let property in England and Wales must be EPC E or better today. The government's interim response of 18 June 2026 proposes EPC B, where cost effective, from 2031 for let buildings over 1,000 m², and drops the EPC C step once planned for 2027. How far solar moves a particular building depends on its fabric and services, which is why the EPC assessor models it before anything is fitted.
Does the grid around Winchester have capacity for export?: Scottish and Southern Electricity Networks is the distribution network operator for Hampshire. Arrays above 3.68 kW per phase connect under G99, and the application sets the export limit. It is part of the design work we arrange.

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