Solar Savings Calculator
Estimate how much a solar PV system could save each year, how much export income it may generate, and how long it could take to pay back the installation cost.
Calculator
The rated output of the panels. A typical UK home system is often around 3–5 kWp.
Expected annual electricity generated per kWp installed.
Your yearly electricity consumption before solar.
The share of generated solar electricity used in the home rather than exported.
What you pay for grid electricity.
What you receive for each exported kWh.
Total upfront cost after any discounts or grants.
Optional yearly running cost allowance.
Used for the long-term savings projection.
Annual performance reduction over time.
How many years to model lifetime savings.
Carbon avoided per kWh of solar generation.
Add a battery effect by increasing self-consumption and adding battery cost.
Estimated solar savings
How the calculation works
The calculator first estimates annual generation from the solar array size and expected yield:
It then splits that generation between electricity used in the home and electricity exported to the grid. Electricity used at home saves money at your import rate. Exported electricity earns money at your export tariff.
For the lifetime estimate, the model applies annual panel degradation and electricity price inflation each year, then subtracts the installation cost. This gives a practical long-term estimate rather than only a simple first-year figure.
Note: This calculator gives a planning estimate only. Real savings depend on roof orientation, shading, location, inverter performance, household usage pattern, tariff terms, installation quality and future electricity prices.
Ways to improve solar savings
- •Shift usage into daylight. Run washing machines, dishwashers and EV charging when the panels are producing.
- •Reduce shading. Even partial shading can cut generation significantly depending on the panel layout and inverter setup.
- •Compare export tariffs. A higher export rate can make a major difference if you send a lot of power back to the grid.
- •Consider battery timing carefully. Batteries can improve self-consumption, but the extra upfront cost can lengthen payback.
- •Size the system sensibly. Bigger systems produce more, but savings depend on how much energy you can use or export profitably.
- •Keep records. Smart meter and inverter data help you check whether the system performs as expected.