Plug-In Solar vs Switching Energy Supplier: Which Saves More?
Is plug-in solar or switching to a cheaper tariff the better saving strategy? We compare both approaches with real UK data.
The Comparison
Both strategies aim to reduce your energy bill. But they work very differently and can actually complement each other.
Switching Supplier: What You Save
The Ofgem price cap (Q3 2026) is 24.5p/kWh. The cheapest fixed tariffs are around 21-23p/kWh. For a household using 2,900 kWh/year (UK average):
| Tariff | Rate | Annual cost | Saving vs cap |
|---|---|---|---|
| Ofgem cap | 24.5p | £711 | — |
| Cheapest fix | 21.5p | £624 | £87/yr |
| Octopus Flexible | 23p | £667 | £44/yr |
Maximum saving from switching: roughly £50-90/year.
Plug-In Solar: What You Save
An 800W system with 55% self-consumption:
| Location | Annual generation | Self-consumed | Saved at 24.5p |
|---|---|---|---|
| South England | 920 kWh | 506 kWh | £124 |
| Midlands | 840 kWh | 462 kWh | £113 |
| North England | 800 kWh | 440 kWh | £108 |
Typical saving: £100-130/year — consistently more than switching supplier.
The Winner: Both
The best strategy is switching to a cheaper tariff AND installing plug-in solar. They're not competing strategies — they compound:
- Switch to the cheapest tariff to reduce the rate on electricity you still buy
- Install plug-in solar to reduce the amount you buy
- Consider a time-of-use tariff to maximise solar value
Cost Comparison
| Strategy | Upfront cost | Annual saving | 5-year saving |
|---|---|---|---|
| Switch supplier | Free | £50-90 | £250-450 |
| Plug-in solar | ~£500-800 | £100-200 | £500-1,000 |
| Both | ~£500-800 | £150-280 | £750-1,400 |
- 800W dual-panel plug-in solar kit
- 600Wh battery with smart scheduling
- App monitoring with real-time generation data
- Balcony, garden & flat-roof mounts available
Doesn't solar saving depend on my tariff rate?
Yes — higher tariffs mean bigger solar savings. On the Ofgem cap (24.5p), savings are solid. On Octopus Agile peak rates (35p+), they're even better.
What if energy prices drop significantly?
Solar payback lengthens if prices drop, but you're still generating free electricity. Switching savings would also shrink in a lower-price environment.
Should I switch supplier before installing solar?
Yes — get on the best tariff first, then add solar. Some tariffs like Octopus Flux are specifically designed for solar households.
Related reading
See how much plug-in solar could save you — with real data for your postcode.