Solwex

Solar calculator 2026: work out the cost and savings of a PV system

Free PV calculator for houses, apartment buildings, farms and businesses in Germany: system size, yield at your location, price range, savings and payback – with EU irradiation data (PVGIS) and market prices as of October 2026.

Step 1 of 13 · Building

What kind of building is the solar installation for?

It determines system size, electricity price and self-consumption.

What kind of building is the solar installation for?

How the solar calculator works

From your postcode the calculator finds your location and asks the European Commission's Photovoltaic Geographical Information System (PVGIS) how much electricity one kilowatt-peak produces per year at your roof pitch and orientation. In Germany a south-facing roof typically yields 950 to 1,150 kWh per kWp – about 990 in Hamburg and 1,140 in Munich.

The system size follows your consumption and the usable roof area. How much solar power you use yourself is estimated by a model fitted to the simulation results of HTW Berlin's independence calculator. From that follow the savings, feed-in revenue, payback and the balance over 25 years.

  • Household electricity 37.0 ct/kWh (BDEW, August 2026), business 23.7 ct/kWh net (Destatis, first half of 2026)
  • Electricity price increase 2 % a year, module degradation 0.4 % a year, running costs 1 % of the investment a year
  • EEG feed-in tariff by system size for 20 years, then a cautious 3 ct/kWh
  • Greenhouse gases avoided: 685 g CO₂ equivalent per kWh of solar power (German Environment Agency)

What does a PV system cost in 2026?

A turnkey 10 kWp rooftop system usually costs €12,000 to €16,000 in 2026 without a battery. Per kWp, small systems are considerably more expensive: the consumer advice centre of North Rhine-Westphalia analysed 71 real offers from 2025 and 2026 – on average €2,090/kWp at 4–6 kWp, €1,410/kWp at 9–10 kWp and €1,010/kWp above 16 kWp.

An installed battery costs about €360 to €510 per kWh, so a 10 kWh battery is roughly €4,000. Since 2023, PV systems and batteries on residential buildings in Germany carry no VAT (§ 12 (3) UStG). Extra costs mainly come from flat-roof mounting, steep roofs, a necessary roof renovation or a new meter cabinet.

Is a battery worth it?

Without a battery a household typically uses 20 to 40 % of its solar power itself; a battery usually doubles that share (Fraunhofer ISE). Every stored kilowatt-hour saves the difference between the electricity price and the feed-in tariff, currently about 29 ct.

As a rule of thumb, plan 1 to 1.5 kWh of battery per 1,000 kWh of annual consumption. Example: with 4,000 kWh of consumption and 8 kWp, the system covers about 35–40 % of the demand without a battery and about 65–70 % with a 5 kWh battery. With a heat pump or an electric car the battery may be larger. Try both variants in the calculator.

Feed-in tariff 2026 and the planned EEG reform

For systems commissioned between 1 August and 31 December 2026, the grid operator pays 7.70 ct/kWh for the surplus fed in, for 20 years (up to 10 kWp; up to 40 kWp 6.66 ct and up to 100 kWp 5.44 ct for the respective share). New systems receive nothing while exchange prices are negative.

The government draft of the EEG 2027 would abolish the fixed tariff for new systems from 2027; as of 12 October 2026 it has not been passed. The calculator uses the rates valid today. If your system is connected only in 2027, the revenue for surplus power may be lower – which makes high self-consumption all the more important.

What the calculator cannot know

The result is a non-binding estimate with a price range. Shading, statics, the condition of the roof and the meter cabinet, the grid connection and your actual load profile are only checked during the site visit. A heat pump needs most of its electricity in winter, when the system produces little – self-consumption can then be lower than estimated.

Sources (as of October 2026)

Read on

Solar for private homes

A PV system sized to your consumption and roof, installed on tiled, metal or flat roofs — with storage and roof renovation if needed.

Solar for farms

Put large barn, shed and hall roofs to work: mounting on trapezoidal sheet and corrugated roofs, roof renovation included.

Commercial solar

Solar for halls, offices and production buildings: daytime self-consumption, east-west on flat roofs, installation while you keep working.

Solar with battery storage

Use solar power in the evening too: storage sized to your consumption, planned with the system or retrofitted.

Prefer to talk to us straight away?

Describe your project – we will get back to you with an assessment and a non-binding offer.

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Frequently asked questions

The questions we are asked most often before a project starts.

How accurate is the solar calculator?

The Solwex solar calculator gives a non-binding estimate with a price range. The yield comes from PVGIS, the European Commission's irradiation service, for your location and roof geometry; self-consumption and self-sufficiency are fitted to the simulations of HTW Berlin. Solwex checks shading, statics and the grid connection during the site visit, and only then is the fixed price set.

What does a 10 kWp PV system cost in 2026?

A turnkey 10 kWp rooftop system without a battery usually costs €12,000 to €16,000 in Germany in 2026. The consumer advice centre of North Rhine-Westphalia found an average of €1,410/kWp for 9–10 kWp across 71 offers. A 10 kWh battery adds about €4,000. On residential buildings, system and battery carry 0 % VAT.

How much electricity does a PV system produce per kWp in Germany?

According to PVGIS, a south-facing PV system with a 35° pitch produces about 990 kWh per kWp a year in Hamburg, 1,040 kWh in Cologne and 1,140 kWh in Munich. East-west roofs deliver about 15 to 20 % less but spread the yield more evenly over the day.

Is a battery worth it in 2026?

A battery usually pays off in 2026 if it matches the consumption: about 1 to 1.5 kWh of battery per 1,000 kWh of annual consumption. It typically doubles self-consumption, and every stored kilowatt-hour saves about 29 ct – the difference between the 37 ct electricity price and the 7.7 ct feed-in tariff. At about €360 to €510 per kWh, a well-sized battery usually pays for itself within its service life.

Which feed-in tariff applies in 2026, and what changes in 2027?

For systems commissioned from 1 August to 31 December 2026, surplus feed-in earns 7.70 ct/kWh up to 10 kWp, 6.66 ct/kWh up to 40 kWp and 5.44 ct/kWh up to 100 kWp, each for 20 years. The government draft of the EEG 2027 would abolish the fixed tariff for new systems from 2027; it had not been passed as of 12 October 2026.

What happens to my data in the solar calculator?

For the calculation the solar calculator only needs the postcode and building details; they are not stored. Only when you request the PDF offer and confirm your email address via the confirmation link does Solwex store your contact details and configuration for the offer. Unconfirmed requests are deleted automatically after 30 days.