Solar
Solar savings calculator
Work out what solar panels could realistically take off your electricity bill, using generation modelled for your own postcode and the prices you actually pay.
The calculator is free, needs no account, and keeps your figures in your own browser.
Open the solar calculatorYou can start with typical UK figures and replace them with yours as you go.
What actually drives the saving
A solar saving is made of two very different things: electricity you generate and use in the house, which avoids buying a unit at your full import price, and electricity you export, which earns a much smaller payment per unit.
Two homes with identical roofs can therefore see very different results. A home that is occupied during the day, runs appliances in daylight or charges a car at home uses more of its own generation and saves more.
What to have ready
Your postcode, roughly how much electricity you buy from the grid in a year, your unit price and standing charge, the export rate you would be offered, and the panel capacity, direction and tilt being proposed. Anything you do not know starts from a clearly labelled assumption you can change.
What this is not
It is an independent planning estimate, not a quotation, a technical survey or a promise of savings. Nobody will contact you, and there is nothing to buy.
Common questions
- How much can solar panels save on a UK electricity bill?
- It depends on how much electricity your home uses, when you use it, your unit price and your export rate. The calculator estimates generation for your area, splits it into electricity you use at home and electricity you export, and prices each part separately rather than quoting an average.
- Why does using solar at home save more than exporting it?
- A unit you use yourself avoids buying a unit from the grid, which is usually worth several times more than the export payment for the same unit. That is why the share of generation you use at home matters more than the size of the system on its own.
- Where does the generation estimate come from?
- Your postcode is used to find an approximate location, and the European Commission's PVGIS service estimates yearly and monthly generation for a roof of that size, direction and tilt. It is a modelled estimate for planning, not a measurement of your roof.
- Does a battery increase solar savings?
- It can, by storing surplus that would otherwise be exported cheaply and using it later. Whether the extra saving justifies the extra cost is a separate question, which the battery calculator works through using an hour-by-hour model.
- Will the saving change if my tariff changes?
- Yes. A higher unit price makes self-used solar worth more, and a better export rate makes surplus worth more. You can change both figures and see the result update immediately.