Solar Savings Calculator
Estimate how much electricity rooftop solar panels would generate, what they would save you each year, how long they take to pay back, and how much CO₂ they avoid in your country.
Payback time
CO₂ avoided, per year
Example figures. Replace them with a quote from an installer. Prices are in your own currency.
How the calculator works
It takes the size of the system in kilowatts-peak and multiplies it by how many kilowatt-hours each kWp produces in a year where you live. That gives your yearly generation.
Part of that power is used in your home and replaces electricity you would have bought. The rest is exported to the grid and paid at the export rate. The two added together are your yearly saving, and the installed cost divided by that saving is the payback time.
Choosing the output figure
The yearly output per kWp is the number that matters most. As a rough guide:
| Setting | kWh per kWp per year | Typical of |
|---|---|---|
| Low sun | 850 | Northern Europe, cloudy coastal climates |
| Moderate sun | 1,050 | Central Europe, northern United States |
| Sunny | 1,350 | Southern Europe, much of the United States |
| Very sunny | 1,650 | Deserts and subtropical regions |
These are approximate. An installer’s quote, or a free tool such as the European Commission’s PVGIS, will give you a figure for your exact roof. Type it into the output field to replace the preset.
What it leaves out
The estimate is for a typical first year. It does not include the slow decline in panel output over time, replacing the inverter, maintenance, subsidies, tax relief, loan interest or future changes in electricity prices. A battery raises the share you use yourself and also the cost.
The CO₂ figure assumes each kWh you generate replaces an average kWh from your country’s grid, using our electricity mix data. In a country with very clean power the saving is small. In a coal-heavy one it is large.
Frequently asked questions
How long do solar panels take to pay for themselves?
Divide the cost of the system by what it saves you each year. With the example figures on this page the payback is shown in the result box. Sunnier locations, higher electricity prices and using more of the power yourself all shorten it.
How much electricity does a 1 kWp solar system produce?
Roughly 850 to 1,000 kWh a year in northern Europe, 1,000 to 1,200 in central Europe and 1,300 to 1,700 in southern Europe and other sunny regions. Roof direction, tilt and shading change the result.
Why does self-consumption matter so much?
Electricity you use yourself replaces power you would have bought at the full retail price. Electricity you export is usually paid at a much lower rate. The higher the share you use at home, the faster the system pays back.
How much CO₂ do solar panels save?
Each kWh your panels generate replaces a kWh from the grid, so the saving depends on how clean your country’s electricity already is. The calculator multiplies your yearly generation by the carbon intensity of the grid in the country you select.
About the data. Carbon intensity of electricity by country is from Ember and the Energy Institute via Our World in Data (CC BY 4.0). Output presets are rounded typical values and are not a substitute for a site survey.
Want to know what your electricity emits today? Convert your kWh to CO₂ for your country.
Open the kWh to CO₂ calculator