UK decision guide
Are plug-in solar panels worth it?
They can be worthwhile when a suitable system produces electricity you can use during the day. The honest answer depends on total cost, current rules, position, shading, tariff and self-consumption—not one national savings figure.
Reviewed 24 July 2026. Savings examples are estimates, not promises. Check the current legal position before buying or connecting a system.
The payback calculation
Generation
Panel size × local solar resource × position and system losses
Useful energy
Generation × the share used while it is produced
Payback
Complete system cost ÷ estimated annual bill saving
Use the calculator with your actual unit rate and expected total cost. Treat its output as a screening estimate rather than a survey or guarantee.
| Factor | Helps | Hurts | What to check |
|---|---|---|---|
| Daytime use | Regular background loads | Empty home and mainly evening demand | When appliances actually run |
| Position | Clear useful sun | Persistent shade | Seasonal shade, direction and mounting limits |
| Cost | Complete, suitable system at a lower total cost | Missing mounting, storage or professional-work costs | The full amount paid, not an advertised component |
| Tariff | Higher avoided import price | Low import price or energy exported without payment | Current unit rate and whether export is eligible |
The five numbers to compare before buying
- Complete installed cost: include panels, inverter, mounting, storage and any professional work.
- Daytime self-use: estimate how much generation you can use while it is produced.
- Conservative annual generation: account for direction, shade and seasonal conditions.
- Current unit rate: use the electricity price from your bill, not an old national average.
- Payback under a weaker case: reject a purchase that works only with optimistic assumptions.
Use your own numbers
Test a conservative case, then vary position, daytime use, tariff and complete cost.
Estimate generation and payback →Sources and trust notes
- Energy Saving Trust: solar generation, use and savings factors
- European Commission JRC: PVGIS solar resource
- PlugInSolarCheck: current UK legal guide
No product on this page is presented as personally tested or guaranteed to achieve a particular saving.