Plug-in solar savings calculator
Could a little sunshine make a difference to your bills? Find out what solar could generate, what you could save, and how long a kit might take to pay for itself.
Your solar outlook
Estimates, not guaranteesA clearer picture of your solar potential.
Tell us about your space and electricity tariff. Your generation, savings, system cost and payback will appear here.
Small-scale solar, from our own UK experience.
A calculator estimate isn’t installation approval. Check the kit’s certified mounting and connection requirements.
The assumptions behind the numbers
Solar yield & orientation
Without postcode data, the existing calculator uses 937.5 kWh per kWp for balcony, wall and ground, and 1,062.5 kWh per kWp for roof. South is 100%, east/west 80%, and north 45%. Balcony and wall panels are assumed angled toward the sun, not vertical. Location-specific PVGIS estimates use 15° tilt for balcony/wall and 30° for ground/roof, with 14% system losses.
Costs, tariffs & payback
Prices come from the existing kit catalogue. Mounting is included where recorded; otherwise £100 per selected panel is added. A linked panel price is added where applicable. Generation uses the kit’s actual power, which can differ from your selected panel count. Savings value annual generation at your peak unit rate. Battery arbitrage uses 75% of nameplate capacity and 365 full cycles a year. Payback divides kit and mounting cost by annual savings. Electrician costs, future tariff changes, export income, shading and battery degradation aren’t modelled. CO₂ offset retains the existing 0.71 kg/kWh factor.
A quick safety check
Only a compliant, certified complete kit with its registered mounting can be installed as a plug-in system. Check the kit’s approval and follow the manufacturer’s instructions.
Battery storage systems require a dedicated connection installed by a qualified electrician — they are legal but not plug-in compliant under SI 2026/848.