Solar panels in the UK: demand, seasons and export income
Guide text reviewed: . This date does not certify current tariffs or validated PVGIS results.
A sound UK solar decision needs more than annual consumption versus annual generation. Summer production does not automatically offset imports on a winter evening, and the export tariff can change whether storing surplus is worthwhile. Open the calculator with the UK preset and use pounds for costs and prices per kWh.
Seasonality matters, especially with electric heating
A home with a heat pump may use more electricity in months with shorter days and less solar generation. The same annual demand distributed differently produces a different saving. Do not infer self-sufficiency because annual generation resembles the kWh on your bills: the grid still covers hourly and seasonal shortfalls.
A battery moves energy between hours; it does not save summer for winter. A larger battery may be underused when there is insufficient surplus. Before adding one, inspect monthly charts and compare weekdays, weekends and overnight vehicle charging with your meter data.
Separate avoided imports from export income
Direct use avoids buying a kWh at the import price. Exported surplus may earn a different amount. The Smart Export Guarantee (SEG), explained by Ofgem, is a Great Britain framework, not one guaranteed rate for every UK home. In Northern Ireland, check local arrangements and requirements separately.
Compare eligibility, metering, certification, price, contract duration and treatment of battery-sourced electricity with each supplier. HeliosROI excludes SEG income and all other export payments. Add them in a separate analysis and deduct foregone export income when surplus is stored. Ignoring this can understate solar-only value and overstate the incremental benefit of a battery.
Dynamic tariffs, electric-vehicle plans and export tariffs may require particular combinations of contracts and equipment. Do not treat the best advertised price as available all year. The daily standing charge does not disappear with solar and is not a per-kWh saving.
Check the roof, connection and quotation
- Geometry and shading: request a site-specific assessment of orientation, tilt, chimneys and nearby buildings. The hourly PVGIS profile requested for 2021 does not certify your roof's output.
- Roof condition: if repairs are needed, decide the work sequence; removing and reinstalling panels is an extra cost.
- Connection and permissions: confirm grid notifications or approvals, possible export limits and planning requirements with the installer, especially for listed buildings. The calculator checks none of these.
- Quotation scope: compare capacity, inverter, scaffolding, protection, labour, paperwork, warranties and applicable taxes rather than just panel count.
See Energy Saving Trust's solar panel guidance and MCS for guidance and certification checks. This page does not claim to have verified any particular installer, offer or grant.
Set up a useful comparison
- Enter twelve months of consumption and your avoidable import price. Keep costs in GBP and tariffs in GBP/kWh; do not mix pence with pounds.
- Replace the indicative cost with a current itemised quotation. Historical references are not a 2026 price survey.
- Calculate solar-only first. Then add storage with location, panels and demand held constant.
- Try a lower avoided price and less daytime demand. Assess export income, losses, replacements and finance outside the model.
The documented British demand-shape source is Elexon, Profile Class 1 — Domestic Unrestricted. It is an aggregate profile, not the readings of a particular home with a heat pump or electric vehicle. Read Elexon's explanation of load profiles and the HeliosROI methodology.
The useful conclusion is not “solar pays back in X years everywhere in the UK”, but a range conditional on your roof, timing and contract. For storage decisions use incremental battery savings, not the entire saving from the panels.