It Depends on Your Electricity Use, Not Your Bedrooms
The right number of panels is driven by how much electricity you use, not the size of your house. The average UK home uses about 2,700 kWh of electricity a year, and for that a system of roughly 3.5–4.5 kWp — typically 8 to 10 modern panels — is the standard recommendation.
Most UK homes end up somewhere between 8 and 14 panels (about 3.5 kWp to 6 kWp). Where you sit in that range depends on your usage and your roof.
Daytime generation powers your home first, then charges a battery for the evening; only the surplus is exported for Smart Export Guarantee income.
Panel Wattage and Roof Direction
Two factors change the panel count for the same system size:
- Wattage — modern panels run 350W–500W. Higher-wattage panels (450W–465W) mean fewer panels for the same kWp, which helps on smaller roofs.
- Direction — a south-facing roof yields the most. East or west-facing roofs still work well but may need 15–20% more panels to match a south-facing array’s annual output.
We assess your specific roof — pitch, orientation, shading — at survey and size accordingly.
Battery, EV and Heat Pump Change the Answer
- Battery: does not generate more power, but lifts your self-consumption from maybe 30–50% to 70–85%. Often a smaller, well-optimised system with a battery beats a larger system without one.
- EV or heat pump: these roughly double a typical home’s electricity demand, so a 5–6 kWp system (12–14+ panels) usually makes sense.
If you are planning an EV charger or heat pump soon, it is normally cheaper to size up front than to add panels later and pay for scaffolding twice.
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The Grid Connection Rules to Know
System size also interacts with grid rules:
- Up to 3.68 kW (single-phase): “fit and notify” (G98) — the installer simply notifies your network operator.
- Above 3.68 kW (single-phase): a G99 application is needed for approval before installation.
- Three-phase supply: systems up to about 11 kW are possible without prior approval.
We handle all of this DNO paperwork for you as part of the installation.
Sizing by Your Actual Electricity Use
The right number of panels comes from your annual electricity use and your roof, not a one-size guess. A modern Aiko Gen 4 ABC panel is around 440–450W, and a Midlands roof generates roughly 850–950 kWh per installed kWp each year.
As a working guide:
- Low use (~2,000 kWh/yr, 1–2 people): ~6–8 panels (~3kWp), generating ~2,800 kWh.
- Average use (~2,900 kWh/yr, family of 3–4): ~10–12 panels (~4.5kWp), generating ~4,000 kWh.
- High use / heat pump / EV (4,500 kWh+): ~14–16 panels (~6kWp+), generating ~5,000–5,600 kWh.
If you run — or plan to run — a heat pump or charge an EV, size up: your electricity demand rises and self-used solar is worth far more than exported units. Roof space is the other limit: each panel needs roughly 2m², so a typical pitched roof face comfortably holds 10–14. Pairing the array with a battery lifts how much you actually use from ~40% to ~80%, which is what makes a larger system pay. We size to your bills and your roof, then show the generation and savings before you commit.
Frequently asked questions
Around 8 to 10 panels (roughly 3.5–4.5 kWp) for a typical home using about 2,700 kWh a year. Homes with an EV, heat pump or high usage usually want 12–14+ panels (5–6 kWp).
You do not have to have one, but a battery raises how much of your own solar you actually use from around 30–50% to 70–85%, which usually improves the payback. We will model both options for your home so you can choose.
Usually yes. Adding an EV charger or heat pump roughly doubles electricity demand, and it is cheaper to install a larger system now than to return and add panels later. We factor your plans into the design.
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