What This Calculator Does
This solar payback calculator works out how many years it takes for your solar system to earn back what you paid for it.
Every kWh your panels make is a kWh you don't buy, or one you sell. Add those savings up year after year, and at some point they pass the price of the system. That point is your payback, or "break-even".
It shows two answers side by side: with and without net metering. In the Netherlands net metering is called "salderen", and it ends on 1 January 2027.
How To Use This Calculator
- In System cost, type the full price: panels, inverter, battery and installation. The system cost estimator can give you a range.
- In Analysis horizon, type how many years to look ahead. It starts at 25, the usual length of a panel output warranty.
- In Annual solar production (year 1), type what your panels make in their first year.
- In Annual home consumption, type your yearly use from your power bill.
- In Electricity price, type what one extra kWh from the grid costs you, taxes included. It starts at €0.26, the Dutch average for 2026.
- In Self-consumption rate, type how much of your solar you use yourself. About 30% without a battery. The self-consumption calculator works out your own figure: paste its Used in the house number, because that one leaves out battery losses.
- In Net feed-in payment, type what your supplier pays per exported kWh, after any feed-in costs.
- Check Yearly electricity price change, Panel degradation and Inverter replacement. The starting values come from the sources in the boxes.
- Read the two results: years to break even and net gain, with and without net metering. Net gain is your total savings minus the system cost. The chart shows your savings growing year by year.
The Formula, In Plain Words
Each year, panels make a little less: 0.5% per year by default. The calculator takes your production times your self-consumption rate as the power you use yourself, but never more than your yearly use. The rest is exported.
Power you use yourself is worth the full electricity price. Without net metering, every exported kWh earns only the feed-in payment.
With net metering, exported kWh cancel out kWh you buy, but only up to what you buy over the year. Any extra still earns only the feed-in payment. That is how salderen works until the end of 2026.
The electricity price grows by your yearly change. The feed-in payment stays flat. Every 12 years a new inverter is paid for.
Then it adds up the savings year by year, minus inverter costs, until they pass the system cost. The net gain is that total at the end of the horizon minus the system cost. It even works out the part of the last year, like 10.8 years instead of just "year 11".
A Worked Example
Take the starting values: a €4,500 system, 4,500 kWh made, 4,000 kWh used, €0.26 per kWh and 30% self-consumption. Feed-in is €0.0125, prices rise 2% a year, panels lose 0.5% a year and a €900 inverter comes every 12 years.
In year one you use 4,500 × 0.30 = 1,350 kWh yourself and export 3,150 kWh.
Without net metering, year one saves 1,350 × €0.26 = €351 plus 3,150 × €0.0125 = €39, or €390. Payback comes after about 10.8 years. After 25 years the savings add up to about €9,666, so the net gain is €9,666 minus €4,500, or about €5,166.
With net metering, 2,650 of the exported kWh cancel out the 2,650 kWh you buy. Year one then saves 4,000 × €0.26 = €1,040 plus €6 for the last 500 kWh, or €1,046. Payback comes after about 4.2 years, and the net gain after 25 years is about €27,082.
A Dutch system bought today falls under the first answer.
What To Watch Out For
Salderen ends on 1 January 2027 by law. After that, suppliers must pay for every exported kWh, at least half the bare supply price until 2030, but they may charge feed-in costs.
Milieu Centraal expects about €0.0125 per kWh on fixed and variable contracts. Check your own contract.
The calculator leaves out fixed grid charges, subsidies, loans and the yearly feed-in fee some suppliers bill. Prices can also move faster or slower than your guess.
Read selling power back to the grid for how export works in other countries.
Hard Words
| Term | What it means |
|---|---|
| Payback period | How many years it takes for savings to add up to what the system cost. |
| Break-even | The moment your total savings equal the price you paid. |
| Salderen | The Dutch net-metering rule: exported kWh cancel out bought kWh one for one, up to what you buy in a year. It ends on 1 January 2027. |
| Degradation | Panels slowly making less power as they age, about 0.5% per year. |
| Feed-in payment | What your supplier pays for each kWh you send to the grid, minus any feed-in costs. |
| Self-consumption rate | The part of your solar power you use yourself instead of exporting it. |
| Inverter | The box that turns the panels' DC power into AC for your home. It lasts about 12 years. |
Common Questions
How long does it take for solar panels to pay for themselves?
It depends on the price, your sun, your power price and how export is paid. In this calculator's starting example, a €4,500 system pays back in about 10.8 years without net metering, and about 4.2 years when exports cancel out bought power. Your own numbers can be very different.
What happens to solar payback when salderen ends in 2027?
Payback gets slower for most Dutch homes. Until the end of 2026, exported kWh cancel out bought kWh at the full price, up to your own use. From 2027, exports earn only a feed-in payment, which is much lower. Using more of your own solar, for example with a battery or by shifting chores to sunny hours, helps close the gap.
What is a good feed-in payment to use?
Use the rate in your own energy contract. Dutch rules say that from 2027 to 2030, suppliers must pay at least half the bare supply price, but they may subtract feed-in costs. Milieu Centraal expects about €0.0125 per kWh on fixed and variable contracts, which is where the calculator starts.
Does a home battery shorten the payback period?
It can, but only if the extra solar it lets you use is worth more than the battery costs. A battery raises your self-consumption, so more kWh are worth the full price instead of the low feed-in payment. Type the Used in the house figure from the self-consumption calculator as the self-consumption rate, add the battery's price to the system cost, and compare.
Why does the electricity price change matter so much?
Your savings grow with the price of power. If prices rise 2% a year, a kWh saved in year 25 is worth about 61% more than in year one. No official forecast exists, so try 0% for today's prices and a few higher values to see the range.
Sources
- Rijksoverheid, Salderingsregeling
- Eerste Kamer, Wet beëindiging salderingsregeling (36611)
- Milieu Centraal, Kosten en opbrengst zonnepanelen
- Milieu Centraal, Zonnepanelen onderhouden, vervangen of wegdoen
- CBS, Verdeling energietarieven 2026
- Belastingdienst, Energiebelasting tarieven
- Jordan and Kurtz, Photovoltaic Degradation Rates: An Analytical Review (NREL, 2013)