Financing Energy-Efficient Roof Renovation: Your Guide to Maximising Grants and Loans in 2025
11 Jun 2025
10
Minutes
Katrin Straub
CEO at nextsure
An energy-efficient roof renovation can reduce your heating costs by up to 20 percent, but the initial investment is high. We show you how to optimise financing with government assistance. Discover the most profitable ways to your new roof.
The topic in brief and concise terms
For an energetic roof renovation, you can receive a BAFA grant of up to 20 percent (maximum 12,000 euros) if you present an individual renovation roadmap (iSFP).
The KfW Supplementary Loan (358/359) offers up to €120,000 in loan amount to cover remaining costs after deducting grants, with interest benefits for incomes below €90,000.
Alternatively, you can deduct 20 percent of the renovation costs (up to 40,000 euros) from tax over three years, provided you are not using BAFA or KfW funding.
Cost Analysis: What an Energy-efficient Roof Renovation Really Costs
The costs of an energy-efficient roof renovation vary greatly depending on the scope and material. You should expect to pay between 150 and 300 euros per square metre. For an average single-family home with 120 square metres of roof area, this means an investment of 18,000 to 36,000 euros. The most expensive, yet also most effective method is above-rafter insulation, which alone costs 90 to 150 euros per square metre. Cheaper alternatives like between-rafter insulation cost about 50 to 100 euros per square metre. Keep in mind that up to 20 per cent of heating energy can be lost through an uninsulated roof. A detailed cost estimate is the first step in developing an appropriate financing strategy.
Secure grants: The BAFA funding as a financial foundation
Das Bundesamt für Wirtschaft und Ausfuhrkontrolle (BAFA) is your first point of contact for direct grants. Under the Federal Funding for Efficient Buildings (BEG), you receive a basic grant of 15 percent for individual measures such as roof insulation. The eligible costs are capped at 30,000 euros per residential unit, which corresponds to a grant of 4,500 euros. Our expert tip: Have an individual renovation schedule (iSFP) prepared in advance. With an iSFP, the funding rate increases to 20 percent and the eligible costs rise to 60,000 euros, allowing you to receive up to 12,000 euros in grants. The commissioning of an energy efficiency expert for the iSFP is also subsidised at 50 percent. Remember to submit the application before starting any construction work. These grants form a solid foundation for your roof renovation financing.
Check credit options: Make use of low-interest loans from KfW
If the grants are not sufficient, the Kreditanstalt für Wiederaufbau (KfW) offers attractive loans. The supplementary loan (KfW 358/359) is specifically intended for renovators who already have a BAFA commitment for an individual measure. You can take out a low-interest loan of up to €120,000 per residential unit to cover the remaining costs. For owner-occupiers with a household income of up to €90,000 per year, there are additional interest advantages of up to 2.5 percent. If you are planning a comprehensive renovation to make your house more energy-efficient, the KfW 261 loan is relevant, which combines loan amounts of up to €150,000 with high repayment subsidies. A repayment subsidy reduces the loan amount you have to repay and is effectively free money. A favourable construction loan is thus within reach. The combination of BAFA grants and KfW loans is a strong duo for your financing.
Realise tax advantages: An alternative to direct subsidies
If you have missed the application deadlines for funding, there is another option: tax deductibility. According to § 35c of the Income Tax Act (EStG), you can deduct 20 per cent of your renovation costs from your taxes spread over three years. The maximum tax relief is 40,000 euros per property. The breakdown is as follows:
In the year of completion: seven per cent of the costs (max. 14,000 euros)
In the following year: seven per cent of the costs (max. 14,000 euros)
In the third year: six per cent of the costs (max. 12,000 euros)
It is important that the property is older than ten years and that you occupy it yourself. Double funding, meaning the combination of a tax bonus and BAFA/KfW funding for the same measure, is excluded. This regulation makes tax deduction a valuable alternative if you want to optimise the financing of your energy-efficient roof renovation retroactively.
Case Study: How the Schmidt Family Optimises Their Financing
Imagine the Schmidt family, who want to renovate their 140-square-metre roof. The total costs amount to 42,000 euros. An energy consultant creates an individual renovation roadmap (iSFP). Thanks to the iSFP bonus, the Schmidt family qualifies for the increased BAFA subsidy of 20 percent. They thus receive 8,400 euros as a direct grant. They finance the remaining 33,600 euros through the KfW supplementary loan. As their household income is below 90,000 euros, they benefit from the maximum interest rate reduction. Through the clever combination of advice, subsidy, and loan, the family reduces their financial burden by over 20 percent. This example demonstrates how a structured approach successfully answers the question, "How do I best finance an energy-efficient roof renovation?"
Step by Step to Financing: A Roadmap to Success
Good planning is crucial to make the most of all funding opportunities. Proceed systematically to avoid mistakes. Here is a tried-and-tested sequence:
Involve energy efficiency experts (EEE): A certified consultant is mandatory for most grants and helps you get the most out of them. The costs for construction supervision are subsidized by 50 percent.
Obtain quotes from specialist companies: Obtain at least two to three detailed quotes for the roof renovation.
Submit grant applications (BAFA/KfW): Submit all applications before signing a contract with a tradesperson.
Wait for financing approval: Only commence construction work after receiving the approval notice.
Have the renovation carried out: Ensure all invoices are well-documented.
Submit evidence and receive payment: After completing the measure, submit the documents to the funding agency.
This structured process secures your financing and prevents you from being left with costs. A modernisation loan without entry in the land register can be a flexible addition here.
Request a personalised risk analysis now
An energy-efficient roof renovation is a complex but rewarding measure. The right financing strategy is the key to success. At nextsure, we understand that every financial decision must be well secured. Have your insurance situation checked for free and receive concrete optimisation suggestions to best protect your property and investment.
More useful links
KfW provides detailed information on funding for energy-efficient renovations, particularly for roof insulation.
Further KfW funding programmes support the energy-efficient renovation of existing properties.
The Federal Ministry for Economic Affairs and Climate Action provides the draft bill for the Building Energy Act (GEG).
The Federal Government provides information on the new Building Energy Act.
The Federal Statistical Office (Destatis) offers statistics on energy consumption in sectors and companies.
The Federal Environment Agency provides data on energy consumption in private households.
FAQ
How can I best finance an energy-efficient roof renovation?
The best financing usually combines a BAFA grant (up to 20 percent) with a low-interest KfW supplementary loan. Alternatively, the tax bonus is an option if no direct subsidies have been applied for. Consulting with an energy efficiency expert can help you find the optimal strategy for your project.
What funding is available for roof renovation in 2025?
In the year 2025, you can rely on the Federal Funding for Efficient Buildings (BEG). This includes grants from BAFA for individual measures and low-interest loans from KfW, such as the Supplementary Loan 358/359 or Loan 261 for efficiency house renovations.
What is the subsidy amount for a new roof covering?
A purely new covering without any energy improvement is not subsidised. The grant is only granted if the measure improves energy efficiency, primarily for roof insulation. The covering can then be partially subsidised as part of the total costs.
Can I apply for grants for roof renovation retroactively?
No, subsidies from BAFA and KfW must always be applied for before the renovation work begins. It is not possible to apply retrospectively. The only exception is the tax bonus, which you can claim on your income tax return after the measure has been completed.
What is an individual renovation road map (iSFP)?
The iSFP is a detailed plan created by an energy efficiency expert that analyses the energy condition of your property and highlights meaningful renovation steps. With an iSFP, you receive an additional funding bonus of five percent from BAFA.
Which costs are eligible for funding in roof renovation?
Eligible costs include all expenses directly associated with energy efficiency improvements. This encompasses material costs for insulation, the services of craftsmen, the new roof covering (as part of the insulation), new roof windows, as well as planning and consulting services provided by an energy efficiency expert.
