Financing a Roof Renovation with Solar Panels: A Guide
7 May 2025
Katrin Straub
Managing Director at nextsure
Planning a roof renovation and considering solar power? Combining both projects is one of the most economical decisions you can make for your home. Learn how joint financing can save you thousands of euros and maximise government grants.
The topic in brief and concise terms
Combine roof renovation and PV installation to save up to €2,000 through synergies with scaffolding and craftsmen.
Take advantage of government subsidies such as the KfW loan 261 with up to 20 percent repayment grant to significantly reduce investment costs.
Benefit from the zero tax rate on PV systems, which reduces acquisition costs by 19 percent and minimises bureaucracy.
Die Entscheidung, eine Dachsanierung mit der Installation einer Photovoltaikanlage zu verbinden, ist mehr als nur eine energetische Modernisierung. Es ist eine strategische Investition, die Ihre Energiekosten um bis zu 80 Prozent senken und gleichzeitig den Immobilienwert erheblich steigern kann. Viele Hausbesitzer scheuen jedoch den anfänglichen Aufwand und die unübersichtlichen Finanzierungsoptionen. Dieser Artikel führt Sie durch den Prozess, zeigt konkrete Sparpotenziale auf und erklärt, wie Sie staatliche Förderungen und die passende Finanzierung für Ihr Vorhaben sichern. So wird aus zwei großen Projekten eine einzige, finanziell optimierte Maßnahme.
Leveraging synergies: Cost savings through combined measures
The joint execution of roof renovation and PV installation creates significant financial advantages. You only need scaffolding once, which alone can save up to €2,000. Additionally, planning and craftsmanship costs for electrics and roofing are incurred only once. This bundling reduces total costs by up to ten percent. Roof renovation also offers the perfect opportunity to optimally prepare the roof's structure and orientation for the solar modules. Such integrated planning not only ensures the longevity of both components for the next 25 years but also lays the foundation for maximum energy yield. Combining both projects is thus the first step towards an optimised financing strategy.
State subsidies as the foundation of your financing
Government support can significantly ease the funding for roof renovations with solar panel installations. Both federal and state governments offer low-interest loans and direct grants to reduce your investment costs. It is crucial to submit these applications before the work begins. Combining different funding programs is often possible and maximises your savings.
KfW Loans: Affordable Money from the Government
The Kreditanstalt für Wiederaufbau (KfW) is a central point of contact for financing. Here are the key programs:
KfW Loan 270 ‘Renewable Energies – Standard’: This program offers a low-interest loan for the purchase and installation of photovoltaic systems and storage.
KfW Loan 261 ‘Residential Building – Loan’: If you carry out the roof renovation according to the Effizienzhaus standard, you can receive a loan of up to 150,000 euros with a repayment grant of up to 20 percent.
A solar loan can complement these subsidies and ensure the residual financing. The right combination of these funds is the key to reducing the monthly burden.
Tax Advantages: The Zero-Tax Rate as a Direct Profit
Since the first of January 2023, homeowners have benefited from a substantial tax relief. For the delivery and installation of photovoltaic systems and their associated storage, a zero percent VAT rate applies. For a system worth 20,000 euros, you directly save 3,800 euros. This advantage applies without bureaucratic hassle for systems on residential buildings.
Additionally, the income from operating PV systems with a capacity of up to 30 kilowatt peak (kWp) on single-family homes is exempt from income and business tax. This applies retroactively from the 2022 tax year and significantly simplifies the annual tax return. You can also claim tax relief for pure roof renovation services according to § 35a EStG. These tax incentives make the acquisition of a photovoltaic system even more attractive.
Alternative financing methods for maximum flexibility
In addition to traditional loans, there are other attractive financing models available. A modernisation loan from your local bank is often straightforward and does not require a land registry entry. The interest rates are usually somewhat higher than those of KfW, but the process is faster. Another option is the building savings contract. If you already have one, you can use the savings and the low-interest loan for renovation. This offers high planning security throughout the entire term. Our expert tip: Compare the terms of a purpose-tied eco-loan with those of an unrestricted instalment loan. Sometimes banks offer special interest benefits for sustainable projects, which can be noticeable over a ten-year term. The choice of the right instrument depends on your financial situation and equity.
Insurance Coverage: The Foundation for a Worry-Free Future
A new photovoltaic system is a value-enhancing measure and must be reported to the insurer. Otherwise, you risk being underinsured. Most residential building insurance policies cover basic damage from fire, storm, or hail, but not all risks. A separate photovoltaic all-risk insurance offers more comprehensive protection. It also covers damage caused by operational errors, short circuits, or animal bites. The annual premiums for such a policy are often only between 50 and 150 euros. Our expert tip: Check whether your existing residential building insurance offers a powerful extension or if a separate policy is the better choice. Comprehensive protection secures your investment for the next two decades.
Conclusion: An investment that pays off multiple times
Combining funding for a roof renovation with a solar panel installation makes economic and ecological sense. You save up to 2,000 Euros through synergies, benefit from government grants, and significant tax advantages. The investment not only reduces your ongoing energy costs by up to 80 percent but also increases the value of your property. With careful planning of financing and insurance coverage, you establish a sustainable and profitable foundation for the future of your home.
Request an individual risk analysis now: Have your insurance situation checked free of charge and receive specific optimisation suggestions.
More useful links
The KfW offers detailed information on the promotion of photovoltaic systems as part of the renovation of existing properties.
On the KfW website, you can find information on the funding of roof insulation during the renovation of existing properties.
The Federal Ministry for Economic Affairs provides information about the government's Solar Package 1 and its measures to promote solar energy.
A press release from the Federal Statistical Office (Destatis) provides relevant data and facts on the topic.
The Consumer Advice Centre offers important guidance on planning a photovoltaic system.
The German Energy Agency (dena) provides information on its support in implementing the photovoltaic strategy.
Current market data on the solar industry in Germany is available from the Federal Association of the Solar Industry (BSW).
The Market Master Data Register (MaStR) of the Federal Network Agency is used for registering energy installations.
The Federal Ministry of Finance answers frequently asked questions about the promotion of photovoltaic systems.
FAQ
Welcher Kredit ist der beste für eine Dachsanierung mit Solaranlage?
Der KfW-Kredit 261 ist oft die beste Wahl, wenn Sie umfassend energetisch sanieren, da er einen hohen Tilgungszuschuss bietet. Für die reine PV-Anlage eignet sich der KfW-Kredit 270. Ein Vergleich mit Modernisierungskrediten Ihrer Hausbank kann sich ebenfalls lohnen.
Muss ich die neue Solaranlage meiner Versicherung melden?
Ja, unbedingt. Die Installation einer PV-Anlage stellt eine Wert- und Risikoerhöhung dar. Ohne Meldung an Ihre Wohngebäudeversicherung riskieren Sie im Schadensfall eine Deckungslücke. Oft ist eine separate Photovoltaik-Versicherung die bessere Lösung.
Wie viel spare ich durch den Nullsteuersatz bei einer PV-Anlage?
Sie sparen die komplette Mehrwertsteuer von 19 Prozent auf den Kauf und die Installation der Anlage sowie des Speichers. Bei Anschaffungskosten von beispielsweise 16.000 Euro beträgt die Ersparnis 3.040 Euro.
Kann ich Förderungen auch nachträglich beantragen?
Nein, in der Regel müssen alle Förderanträge, insbesondere bei der KfW und dem BAFA, vor der Auftragsvergabe und dem Beginn der Baumaßnahmen gestellt und genehmigt werden. Eine nachträgliche Förderung ist ausgeschlossen.
Lohnt sich eine Solaranlage auch ohne Dachsanierung?
Ja, wenn Ihr Dach in einem guten Zustand ist und noch eine lange Lebensdauer hat, kann sich die Installation einer PV-Anlage auch ohne Sanierung lohnen. Die Kombination ist jedoch kosteneffizienter, wenn ohnehin Arbeiten am Dach anstehen.
Was deckt eine Photovoltaik-Allrisk-Versicherung ab?
Zusätzlich zu den Standardgefahren wie Feuer, Sturm und Hagel deckt sie oft auch Schäden durch Bedienungsfehler, Vandalismus, Tierbiss, Kurzschluss und Ertragsausfall ab. Der Schutz ist somit deutlich umfassender als bei einer reinen Wohngebäudeversicherung.
