Estimate how many solar panels your home may need, how much roof space could be required, your likely system size, possible savings, export income and simple payback period.
Use this calculator before speaking to installers. It gives a practical estimate based on electricity use, roof space, UK region, panel wattage, roof direction, shading, battery storage, EV charging and heat pump demand.
The main result shows how many panels may suit your home, then gives a sensible range so the estimate stays realistic.
The calculator checks rough roof space and flags larger systems that may need DNO approval before installation.
It estimates home-use savings, export income, installed cost and simple payback using adjustable electricity and export rates.
Enter a few details below. The result is a planning estimate only, not a final solar design, quote or financial recommendation.
This calculator is provided as a general homeowner planning tool. It is not a solar quote, MCS design, structural assessment, electrical design, payback guarantee, tariff recommendation or financial advice.
Real solar panel suitability depends on roof condition, roof structure, orientation, pitch, shading, usable roof area, fire access, fixing system, inverter sizing, cable routes, consumer unit condition, DNO/export requirements, scaffold access, local constraints and installer design.
The results should be used to understand the likely range before speaking to qualified solar installers. No phone number is requested, no enquiry is sent to installers and there is no obligation to buy anything.
These are rough planning examples. The final number of panels depends on electricity use, roof space, panel size, roof direction, region, shading, inverter design, DNO requirements and whether you use power during the day.
| Home scenario | Possible panel range | Approx system size | Useful note |
|---|---|---|---|
| Small home or low electricity use | 4–8 panels | 1.6–3.6 kWp | Good for lowering bills, but roof direction and daytime use still matter. |
| Average 3-bed home | 8–12 panels | 3.2–5.4 kWp | Often the common domestic range for a straightforward home solar system. |
| Larger family home | 12–16 panels | 4.8–7.2 kWp | Battery storage may become more useful if evening electricity use is high. |
| Home with EV charging | 12–20+ panels | 4.8–9.0 kWp | EV mileage and charging times can significantly affect the best system size. |
| Home with heat pump | 12–22+ panels | 4.8–10.0 kWp | Heat pump demand can increase annual electricity use, especially in winter. |
| Limited or awkward roof space | Based on physical fit | Varies | The best system may be the largest sensible array that safely fits the roof. |
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Many average UK homes may need around 8 to 12 solar panels, but the right number depends on annual electricity use, roof space, panel wattage, roof direction, shading, UK region and whether the home has EV charging or a heat pump.
A simple method is to estimate your target annual solar generation, divide it by the expected annual generation per kWp in your region, then divide the required system size by the wattage of each panel. This calculator also adjusts the estimate for roof direction and shading.
Annual electricity use is usually better. Bedroom count can give a rough guide, but two homes with the same number of bedrooms can use very different amounts of electricity depending on appliances, working from home, heating, cooking, hot water, EV charging and heat pump use.
As a rough planning guide, allow around 2 square metres per solar panel. The real usable area may be lower once roof edges, ridges, valleys, chimneys, skylights, access zones, fire access and the exact mounting layout are considered.
Not usually. A battery does not generate electricity, so it does not normally reduce the number of panels needed. It can help you use more of the electricity your panels produce, especially if you are out during the day and use more power in the evening.
Solar self-consumption is the amount of solar electricity your home uses directly instead of exporting it to the grid. Higher self-consumption usually improves the value of solar because using your own electricity normally saves more than exporting it.
SEG stands for Smart Export Guarantee. It is the payment some energy suppliers make for electricity exported from solar panels to the grid. Export rates vary by supplier and tariff, so the calculator uses a simple adjustable export rate.
Possibly. EV charging can add a significant amount to annual electricity use, so a home with an electric car may benefit from a larger solar system. The best size depends on mileage, charger use, charging times and available roof space.
A heat pump can increase annual electricity demand, so it may increase the number of solar panels needed if you are trying to cover a larger share of your total electricity use. However, heat pump demand is often highest in winter, when solar generation is lower.
Usually no. Solar panels generate electricity during daylight, but a home may still import electricity at night, in winter or when usage is higher than generation. Battery storage can reduce grid use, but it does not guarantee zero electricity bills.
Yes. Many east or west-facing roofs can still work for solar, although annual output may be lower than an ideal south-facing roof. East and west roofs may also spread generation across the morning and afternoon, which can suit some homes well.
Mostly north-facing roofs are usually less favourable for solar because they receive less direct sunlight. Solar may still be possible in some cases, but the generation estimate and financial return should be checked carefully by a qualified installer.
Some larger solar systems, systems above typical small domestic export limits, and certain battery setups may need approval or notification through the local Distribution Network Operator. A qualified installer should advise on DNO, G98, G99 and export limitation requirements.
No. This is a no strings attached planning estimate for homeowners. It is not a quote, MCS design, structural survey, electrical design, payback guarantee, tariff recommendation or financial advice. A qualified solar installer should confirm the final system.
