Check your electricity tariff
At 32 ct/kWh a tariff check is worth it. At 26 ct/kWh you save
€145 per year
on the 2,418 kWh you still buy from the grid after the solar system has covered its share.
Based on your annual consumption of 4,000 kWh.
Your system
PV array size
Battery storage
Location and mounting
Roof orientation
Your household
Heat pump, EV and other consumers
Add a consumer
Consumers that run in the daytime raise self-consumption the most.
Total consumption: 4,000 kWh per year
Prices
Currency
Default: the German EEG rate, weighted (first 10 kWp at 7.70 ct/kWh, the part above at 6.66 ct/kWh). For your array: 7.70 ct/kWh.Enter the rate you get for exported power, for example under UK SEG or US net metering.
Typical turnkey price for this system: €10,500
Exported power earns the feed-in tariff above. Set it to what your utility or scheme pays. Battery and installation prices vary by installer and country.
Your result
Pays for itself after 10.6 years, then saves €988 every year.
Payback time
10.6years
Selected setup: 10.6Scale in years, shaded: the first 20 years
A 5 kWh battery would save another 1,125 kWh/year (+€264), but shortens the payback by 0.4 years.
Annual bill reduction
€988per year
€82.35 per month, including €482 feed-in income
20-year net return
+€9,263
after subtracting €10,500 purchase price
Installer quotes
8 kWp rooftop system without storage
About 18 panels of 440 Wp · String inverter
Typical turnkey price €10,500
Where the solar energy goes
- 20 %Used directly1,582 kWh
- 0 %Used via battery0 kWh
- 80 %Paid grid export6,258 kWh
Battery losses (about 10%) are already deducted.
Cumulative cash flow in €, starting at −€10,500
- Selected setup
- With 5 kWh (comparison)
* Partner link. If you buy or sign a contract we may earn a commission. Your price stays the same.
Assumptions and limits
Model with 980 kWh/kWp annual yield (south-facing, central Europe around 51° N), constant electricity price and no degradation. Daytime demand is 40% of base consumption, 30% of heat pump and 35% of EV consumption. The battery runs at 90% efficiency and at most 250 full cycles a year. Export earns the feed-in rate. Real results depend on location, shading, load profile and installer prices.
Getting started
Your next steps
A short checklist from the first idea to a running system. The search buttons open Google with a matching query for your country.
Claim funding before you sign anything
Many grants, cheap loans and tax breaks are only paid if you apply before you sign a contract or place an order. Check national, regional and local programmes first, then sign.
Search on GoogleCheck your roof
Have the roof's condition, load capacity and shading checked. If the roof needs work in the next 10 to 15 years, do it before the panels go on, because taking them off and refitting them later is expensive.
Compare two or three quotes
Compare the price per kWp, the panel and inverter brands, warranties and what is included. In this model a turnkey system costs about €1,310 per kWp.
Size the battery to your evening use
As a rule of thumb, about 1 kWh of storage per kWp is plenty, and more rarely pays off. Switch the battery on and off in the calculator above to see the difference for your household.
Register the system
Your installer usually handles the grid operator. You must enter the system in the Marktstammdatenregister within one month of commissioning, or the feed-in payment can be cut.
Search on GoogleTrack the real payback
Once it runs, log your meter readings in TrackIt+ to see whether the system keeps its promise and when it has paid for itself.
Get TrackIt+
Android app
TrackIt+
Track your real payback and your whole household
TrackIt+ for Android goes far beyond solar. Log your meters, your PV system, your cars and your finances in one app, see yearly cost and savings forecasts and get a heads-up before contracts end. It works offline, needs no account and is free to start.
- Electricity, gas, water and heating meters
- Solar generation, feed-in, self-use and payback progress
- Cars, hybrids and EVs with mileage, fuel and charging costs
- Savings plans, loans, insurance and fixed costs
- Free for up to 10 trackers. PRO is a one-time purchase, no subscription
FAQ
Rooftop solar: questions and answers
How long do solar panels take to pay for themselves?
Often 8 to 16 years. It depends on four things: what the system costs, how much sun your roof gets, how much of the power you use yourself, and what you're paid for the rest. A high electricity price and a high share of self-consumption shorten payback; a battery usually lengthens it. Panels then keep producing for 25 years or more. Enter your own numbers above to see your break-even year.
Is solar still worth it in 2026?
Usually yes, if you own your roof and plan to stay. Panels have become much cheaper, and every kWh you use yourself saves the full electricity price. In the US, the 30% federal tax credit for homeowner-owned systems (25D) ended for systems installed after 31 December 2025, so payback is longer there than a year ago; state and utility incentives still differ a lot. In Germany, systems up to 30 kWp on homes are VAT-free.
Is a solar battery worth it?
It depends on what exported power earns. Where exports pay little, such as low feed-in tariffs in Germany or net billing in California, a battery lets you use more of your own power in the evening. Where net metering credits exports at the full price, a battery rarely pays for itself. In this model a battery usually adds a few years to payback. Compare both in the calculator before you buy.
What size solar system do I need?
Start from your yearly electricity use. A household using 4,000 kWh a year often fits 6 to 10 kWp. Add more if you plan a heat pump or an electric car, because both add consumption you can move into sunny hours. Each kWp needs about 5 to 6 square metres of roof. Turn on the heat pump and EV options above to see how they change your payback.
Should I buy, lease or sign a solar PPA?
Buying, with cash or a loan, gives the highest long-term return, and this calculator assumes a purchase. A lease or power purchase agreement needs no money up front, but the provider keeps most of the savings and you sign a contract of 20 years or more. That can make it harder to sell your house. Compare the monthly cost of a lease with the yearly saving shown here.
What do I get paid for the power I export?
That depends on where you live. In Germany, new systems up to 10 kWp get a fixed feed-in tariff of about 7.7 cents per kWh for 20 years. In the UK, the Smart Export Guarantee rate depends on your energy supplier. In the US, net metering and net billing rules vary by state and utility. Enter your rate in the calculator's fine-tune settings.
How many quotes should I get?
At least two or three. Prices for the same system often differ by thousands. Compare the price per kWp, the brands of panels, inverter and battery, the warranty and what's included, such as scaffolding and registration. Use the price per kWp from the calculator as a check against each quote.
Do solar panels lose efficiency over time?
Slowly. Good panels lose about 0.3 to 0.5 percent of their output a year and usually come with a 25 to 30 year performance warranty. Plan to replace the inverter once, often after 12 to 15 years.
How do I check what my system really earns?
Every payback figure is a model. Read your electricity meter and the inverter on the same day each month: that shows how much solar power you use yourself, how much you export and how your bill changes. TrackIt+ for Android logs meter readings offline, and its PV cockpit shows how far your system has really paid for itself, so you can compare reality with this calculator.