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Commercial building solar panels in Windsor

Most commercial roofs around Windsor already carry plant, a parapet and an access hatch, and the space between them is where the array goes. 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.

901 kWh per kWp a year at this latitude, so a 210 kWp array models at about 189,000 kWh. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.

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60 m 32 m N plant screen shade, kept clear stair core edge strip 1.5 m phase 1
Drawing Windsor commercial roof
Roof 60 x 32 m, 1,920 m²
Array 210 kWp, east-west
Yield 189,000 kWh/yr
Scale 1:400 / Rev A / SL4

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.

31,560
people in the Windsor built-up area (ONS Census 2021)
1,330
office properties on the rating list in Windsor and Maidenhead (VOA, March 2025)
1,230
retail properties, 40 of them large-format (VOA, March 2025)
2
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.

Commercial rooftop solar across Berkshire

Yield on a Windsor commercial roof

Modelled irradiation here is 1,157 kWh per square metre a year on a low-tilt array, which works out at 901 kWh for every kWp installed (EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss). That is within a few percent of the mean across the towns we cover, so the weather is not what decides the case here. Opening hours are.

How many commercial buildings Windsor and Maidenhead has

On the Valuation Office Agency's count, Windsor and Maidenhead holds 1,230 retail and 1,330 office properties on the rating list. By office stock the district sits above the median of the 318 districts in England and Wales; by retail stock it sits above the median of the 318 districts in England and Wales.

40 of those retail properties are superstores, large food stores, large shops or retail warehouses, together about 71,000 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 280 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.

Commercial rooftop solar already planned near Windsor

The Renewable Energy Planning Database records 2 roof-mounted schemes on leisure and hospitality and supermarket and retail buildings in this postcode district. These are other organisations' projects, listed from the public record, not ours.

One of them was put through planning by UREF LP, an investment manager or landlord rather than the occupier. That is the pattern MEES is pushing towards: the owner fits the array to protect the EPC rating and the letting, then sells the power to the tenant.

Scheme Applicant Type Capacity Status
Car Park Legoland Windsor Resort, Winkfield Road Legoland Windsor Park Limited leisure 1.2 MW Awaiting Construction
Waitrose, King Edward Court UREF LP (landlord) retail 0.41 MW Awaiting Construction

The built-up area holds about 31,560 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 SL postcodes, SL4 outward.

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

What a Windsor roof makes, month by month

Modelled output per kWp installed, for a shallow-pitched south-facing array. Source: EU PVGIS v5.2.

050100Jan: 25 kWh per kWpJanFeb: 38 kWh per kWpFebMar: 72 kWh per kWpMarApr: 103 kWh per kWpAprMay: 120 kWh per kWpMayJun: 124 kWh per kWpJunJul: 125 kWh per kWpJul125 kWh Aug: 106 kWh per kWpAugSep: 83 kWh per kWpSepOct: 52 kWh per kWpOctNov: 31 kWh per kWpNovDec: 22 kWh per kWpDec

Jul produces 5.7 times what Dec does on the same roof. A 210 kWp array here models at about 189,000 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
MonthkWh per kWp210 kWp array
Jan255,250
Feb387,980
Mar7215,120
Apr10321,630
May12025,200
Jun12426,040
Jul12526,250
Aug10622,260
Sep8317,430
Oct5210,920
Nov316,510
Dec224,620
Source: EU PVGIS v5.2
FIG. 2 Windsor against the rest of Berkshire
  • Thatcham910
  • Reading907
  • Maidenhead905
  • Newbury904
  • Slough903
  • Windsor901
  • Wokingham898
  • Bracknell891

Windsor ranks 6 of 8 towns we cover in Berkshire on modelled yield, against a national mean of 886 kWh per kWp. The county runs from 891 to 910, a spread of 19 kWh per kWp. Within Berkshire that difference is small enough to ignore: where the building sits is not what decides this scheme, your consumption pattern is.

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 SL4

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
Russells Farm, Windsor Great Park - Solar panels The Crown Estate 0.21 MW Roof Revised
Russells Farm, Windsor Great Park - Solar panels The Crown Estate 0.21 MW Roof Awaiting Construction
Car Park Legoland Windsor Resort, Winkfield Road - PV solar photovoltaic Legoland Windsor Park Limited 1.2 MW Roof Awaiting Construction
St Johns Beaumont School, Priest Hill - Solar Panels St Johns Beaumont School 0.26 MW Roof Application Refused
Waitrose, King Edward Court - Solar Panel Array UREF LP 0.41 MW Roof Awaiting Construction
The Windsor Boys School, Maidenhead Road - Solar Panels Solar Options for Schools Limited 0.49 MW 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 Berkshire the planning database records 83 solar schemes totalling 317 MW, of which 8 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.

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

Questions about solar in Windsor

How much would solar on a commercial building in Windsor generate?
The model gives 901 kWh for every kWp installed here, so 210 kWp is about 189,000 kWh a year before shading losses. Allow roughly 1,390 m² of roof for it. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.
Is planning permission needed for panels on a Windsor 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 Windsor and Maidenhead 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 Windsor?
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 Windsor have capacity for export?
Scottish and Southern Electricity Networks is the distribution network operator for Berkshire. 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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