Most homes in the Black Country need between six and ten solar panels. That is the short answer, and it comes from three numbers you can check: how much electricity your house uses in a year, how much a panel makes on a roof in Dudley, Walsall, Sandwell or Wolverhampton, and how big a system can connect to your supply without waiting for approval. This guide works through each one with the official figures, so you can size your own roof before anyone quotes. If you are ready for a design, start on our solar panels in the Black Country page.
Step one: how much electricity your home uses
Your annual use is on your bill or in your supplier’s app, in kWh. If you don’t have it, Ofgem’s typical domestic consumption values are a fair guide. Since 1 July 2026 Ofgem puts a low-use home on a standard single-rate meter at 1,600 kWh a year, a medium home at 2,500 kWh and a high-use home at 3,800 kWh.
Step two: what a panel makes on a Black Country roof
The European Commission’s PVGIS model puts a south-facing array at 35 degrees in Oldbury at 960 kWh a year for every kWp of panels, with 14% system losses. Every Black Country town sits within about 1% of that, from Stourbridge at the low end to West Bromwich at the high end, so the postcode barely matters. What matters is the roof.
Divide your annual use by 960 and you have the size of system that matches it over a year.
The sizing table
| Household (Ofgem typical use) | Use a year | System that matches it | Panels at 450 W | Average installed cost, West Midlands |
|---|---|---|---|---|
| Low | 1,600 kWh | about 1.7 kWp | 4 (1.8 kWp) | about £3,200 |
| Medium | 2,500 kWh | about 2.6 kWp | 6 (2.7 kWp) | about £4,800 |
| High | 3,800 kWh | about 4.0 kWp | 9 (4.05 kWp) | about £6,600 |
Costs use the Department for Energy Security and Net Zero’s 2025/26 averages for the West Midlands: £1,778 per kW for systems up to 4 kW and £1,628 per kW for 4 to 10 kW. Averages include every job in the region, so treat them as a guide, not a quote. Battery costs are separate and are on our solar panels and battery cost page.
Why matching your annual use is only the start
A system sized to your year makes far more than you use in summer and far less in winter. Per kWp, PVGIS has an Oldbury roof making about 116 kWh in June and 33 kWh in December. A 4 kWp array therefore makes about 464 kWh in June and about 133 kWh in December, against a medium home’s average of about 208 kWh a month. Summer surplus goes to the grid; winter shortfall comes from it. That is why the right size depends on what you will do with the surplus, not only on the annual total.
East and west roofs
Plenty of Black Country terraces and semis have a roof that faces east and west rather than south. PVGIS puts an east-facing slope in Oldbury at 772 kWh per kWp a year and a west-facing slope at 750, about a fifth less than south. Add a panel or two to make up the difference, or split the array across both slopes so it generates from morning to evening. A north-facing slope is usually not worth covering.
The 3.68 kW connection limit
Your home’s supply decides how big a system can connect without waiting. On a single-phase supply, the norm for a Black Country house, a system that can export up to 16 amps, about 3.68 kW, is connected under the G98 process: the installer notifies the network operator within 28 days. Anything larger needs a G99 application and approval from the network operator before it is connected. Batteries count towards the limit if they can export. The whole Black Country is on National Grid Electricity Distribution’s West Midlands network, so the same rules apply from Bilston to Stourbridge.
How much roof you have
The panel count also has to fit. A typical Black Country semi has one main roof slope, and nearly half of homes in Dudley, Sandwell, Walsall and Wolverhampton are semi-detached according to the 2021 Census. Chimneys, roof windows, vents and the gap kept clear at the edges all take space. The only reliable count is a measured layout of your own roof, which is the first thing we draw.
When to go bigger
Three things justify more panels than your current use suggests. A battery, which stores daytime surplus for the evening. An electric car charged at home, which can add more to your annual use than the rest of the house. And a heat pump, which moves your heating onto electricity. If any of those is likely in the next few years, size for it now: adding panels later means a second set of scaffolding and often a second inverter.
What the extra panels are worth
A unit of solar electricity you use at home saves the full unit rate: 26.32p per kWh at the Ofgem price cap’s GB average for October to December 2026. A unit you export earns whatever your export tariff pays: Octopus Outgoing pays 12p per kWh at the time of writing. That gap is the whole argument for sizing to your use and adding storage before adding panels. Our home battery storage page covers the batteries we fit.
Planning permission
Almost no Black Country home needs it. Panels on a house roof are permitted development if they project no more than 0.2 m from the roof slope and sit no higher than the highest part of the roof, excluding the chimney. Listed houses need consent. In a conservation area the national rule only stops panels on a wall, balcony or roof enclosure that fronts a road, so a roof slope facing the street is still allowed.
VAT
Installing solar panels and batteries in a home is zero-rated for VAT until 31 March 2027, after which the rate is due to return to 5%.
Sizing your own roof
Take your annual kWh from your bill, divide by 960, and round up to a whole number of panels; add a panel or two for an east or west roof and more if a battery, car or heat pump is coming. Then check the result against the 3.68 kW limit and your roof. The town-by-town figures for what a 4 kWp system makes and is worth are on our Black Country solar panels page.
Sources
- Household use: Ofgem, “Review of typical domestic consumption values: decision” (May 2026), values in use from 1 July 2026
- Yield: European Commission JRC, PVGIS 5.3 (SARAH3), Oldbury (52.505, -2.016), 35 degrees, south, east and west, 14% system loss: re.jrc.ec.europa.eu/pvg_tools/en/
- Costs: DESNZ, Solar PV cost data, 2025/26 Total Installed Cost workbook, “Regional costs (TIC)”, West Midlands: gov.uk/government/statistics/solar-pv-cost-data
- Unit rate: Ofgem, energy price cap 1 October to 31 December 2026, GB average Direct Debit electricity
- Export: Octopus Energy, Outgoing Octopus: octopus.energy/smart/outgoing
- Connection limits: Energy Networks Association, EREC G98 and G99
- Housing: ONS Census 2021, TS044 Accommodation type
- Planning: GPDO 2015, Schedule 2, Part 14, Class A
- VAT: HMRC VAT Notice 708/6