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Enter what the system costs, how much it produces, how much of that you use yourself and the prices. Power you use yourself saves the electricity price, power you feed into the grid earns the feed-in tariff. The result is a simple payback time.

Enter your values

Total cost installed, after any subsidy you will really get.
Where do I find this?

Use the total of the offer: panels, inverter, mounting and installation.

Subtract grants that are paid out to you. Tax rules differ by country, so check them separately.

From your offer, or from the Solar Panel Output Calculator.
Where do I find this?

Your installer's offer states the expected yearly yield in kWh. You can also estimate it with the Solar Panel Output Calculator.

Self-consumption: the part of the production used in your home (0 to 100).
Where do I find this?

Without a battery many homes use around 25 to 35 % of the production themselves, more if someone is home during the day or if you have a battery or an electric car.

The installer's simulation gives the figure for your home.

What you pay per kWh from the grid, from your bill.
Where do I find this?

Look for 'price per kWh' or 'Arbeitspreis' on your electricity bill. 32 ct = 0.32.

What you are paid per kWh you feed into the grid.
Where do I find this?

Your grid operator or installer states the feed-in tariff. It is fixed for a period, often 20 years, and depends on the size and the date of commissioning.

Insurance, cleaning, meter fees. Leave 0 if none.
Where do I find this?

Add what you expect to pay per year for insurance, maintenance and meter fees.

Only changes the symbol; no exchange rate is applied.

Result

Enter your values to see the result.

Payback time
– years
Benefit per year
–
Saved on your bill
–
Feed-in income
–
Net gain after 20 years
–

Want this tracked for you? UtilityControl logs your meters and costs automatically.

How it is calculated

  • Own use (kWh) = production × share used ÷ 100; fed in = production − own use
  • Benefit per year = own use × electricity price + fed in × feed-in tariff − running costs
  • Payback (years) = system cost ÷ benefit per year; net gain after 20 years = 20 × benefit − system cost

Example

4,750 kWh a year, 30 % used at home: 1,425 kWh × 0.32 = 456 saved, and 3,325 kWh × 0.08 = 266 earned, together 722 a year. A system costing 8,000 pays back in about 11 years.

What this estimate leaves out

This is a simple payback. It ignores panel ageing, changing electricity prices, loans, tax effects and the value of a battery. A higher electricity price or more own use shortens the payback.

Written and reviewed by QLines, Cologne · Last reviewed

Read the PV and heat pump planning guide (German)

FAQ

Frequently Asked Questions

How long does it take for solar panels to pay for themselves?

Divide the system cost by the yearly benefit: savings on your electricity bill plus the feed-in income, minus running costs. With the example values it is about 11 years, but it depends on prices, sun and how much power you use yourself.

What is self-consumption?

The share of your solar production that you use in your own home instead of feeding it into the grid. Each self-used kWh saves the electricity price, which is usually much higher than the feed-in tariff.

Does a battery shorten the payback?

A battery raises self-consumption, but it also costs money. Enter a higher self-consumption share and the higher system cost to compare, or ask the installer for both simulations.

Is the result guaranteed?

No. It uses constant prices and no ageing. Real production and prices change from year to year.

More free calculators

Electricity Bill Calculator

Estimate your electricity bill from the kWh used, your price per kWh, a fixed fee and tax.

Track your meters instead of calculating by hand

UtilityControl keeps your readings, usage and costs for every meter and location, and it starts free.

See UtilityControl Pricing