Savings come mainly from electricity you generate and use at the same time. The government’s “up to £110 a year” is a headline estimate, not a guarantee for your home.
Generation is not the same as avoided imports
Annual generation is everything the panels produce. Self-consumption is the share your home uses as it is produced. Surplus exported without payment does not reduce your import bill.
For example, 600kWh generated with 60% self-consumption offsets 360kWh. At an illustrative 25p/kWh, that saves £90 a year. Those are example inputs, not a tariff quote or a prediction.
What the government’s figure means
The August announcement describes possible savings of up to £110 a year. Direction, shade, panel rating, weather and household demand can all change the result.
A good generating position matters, but so does using electricity in daylight. A home empty for most of the day may use a smaller share directly.
Use the complete project cost
Count the panels, approved inverter and lead, mounts, delivery and professional work. Consider maintenance and eventual component replacement in a longer-term decision.
Simple payback is total cost divided by annual saving. £600 divided by £90 is about 6.7 years, before tariff changes, maintenance, degradation or financing.
When the numbers do not stack up
- Substantial shade during useful daylight.
- Little daytime demand and no confirmed export payment.
- High mounting or electrical work costs.
- Expecting a small kit to cover most of a large home or an EV.
- Moving before the estimated payback.
Use the calculator as a first filter
Our calculator uses explicitly simplified regional, angle and shading assumptions. It does not run a postcode survey or use live weather. The displayed range is a sensitivity check, not a statistical confidence interval.
PVGIS, from the European Commission’s Joint Research Centre, can provide a more location-specific generation assessment. It still needs suitable inputs and does not establish installation safety.
Good questions
Will it remove my electricity bill?
No. You still import when demand exceeds generation and at night. The standing charge normally remains.
Can I count export payments?
Only after the supplier confirms your exact setup and metering qualify. Our calculator assumes no export payment.
Prepared from the linked sources. This is guidance, not a product certification or an assessment of your home. Tell us about a correction.