Good news for investors: KfW has massively reduced the interest rates for the “Climate-friendly new build” program. What this means in concrete terms, who benefits and how you can finance cleverly now.
Historic KfW interest rate cut from the end of September 2025
The Federal Ministry of Construction, KfW Bank and the Federal Ministry of Housing, Urban Development and Building made a groundbreaking decision for the promotional programs in new construction at the end of September 2025:
The interest rates for the KfW program “Climate-friendly new residential construction” (KfW 297 / 298) were significantly reduced. This reduction in interest rates for KfW promotional loans is part of the German government’s comprehensive housing and climate strategy and is intended to boost climate-friendly housing construction again.
The new KfW funding conditions will make energy-efficient homes significantly more attractive financially. The measure comes at a crucial time: after years of rising construction costs, interest rate increases and declining new construction activity, KfW’s interest rate promotion sends a clear signal. Building owners, families and investors benefit from more favorable loans for climate-friendly residential buildings and interest conditions that can be planned for the long term.
With the new interest rate policy, the German government is creating concrete incentives to make sustainable construction, energy-efficient new builds and the purchase of climate-friendly residential property much more attractive again.
The new conditions of KfW Bank in detail
In the KfW program “Climate-friendly new residential construction” (KFN, program 297 / 298), the effective annual interest rate for terms of up to 10 years has been reduced from 2.23% to just 1.13%. KfW Bank has thus halved the interest rate – a historic step for promotional loans for new builds.
Compared to market interest rates of around 3.3% to 4.0%, there is a considerable advantage for builders and owners who want to finance their efficiency house. The interest rate advantage of up to three percentage points noticeably reduces the monthly burden and improves the financing conditions for climate-friendly residential buildings.
Important key data of the KfW loan:
- Loan amount: up to 100,000 euros per residential unit
- Prerequisite: Efficiency House Standard 40
- Sustainability certification required (quality seal for sustainable buildings)
- Fixed interest rate: 10, 20 or 35 years
- Repayment-free start-up years: up to 3 years
- 100 % payout, no discount
- Only applies to new construction, not to renovation
Concrete calculation examples: How much you really save
To illustrate the scale of the savings, we use a realistic example of a KfW subsidy of 100,000 euros:
Example: New-build detached house with KFN subsidy
Initial situation: The Schmidt family builds a new Efficiency House 40 and applies for a KfW subsidized loan of EUR 100,000 with a fixed interest rate for 10 years.
Variant 1 – With new KfW interest rate (1.13%):
- Monthly installment: approx. 865 euros
- Total interest burden over 10 years: approx. 5,900 euros
- Residual debt after 10 years: approx. 0 euros (with full repayment)
Variant 2 – With the old KfW interest rate (2.23%):
- Monthly installment: approx. 920 euros
- Total interest burden over 10 years: approx. 11,100 euros
- Additional costs: approx. 5,200 euros over 10 years
Variant 3 – With current market interest rate (3.7%):
- Monthly installment: approx. 996 euros
- Total interest burden over 10 years: approx. 19,500 euros
- Additional costs: approx. 13,600 euros over 10 years
The savings are impressive:
- Compared to the current market interest rate, you save over 13,600 euros in 10 years
- Monthly relief: 131 euros compared to the market interest rate
- Even compared to the old KfW interest rate, you still save 5,200 euros
Major construction project: Semi-detached house with two residential units
For a new building with two residential units, the possible subsidy amount is doubled:
Funding amount: 200,000 euros (2 x 100,000 euros)
- Savings compared to market interest rates: over 27,000 euros in 10 years
- Monthly relief: 262 euros
These figures show impressively that the KfW subsidy is not just a nice extra, but can make the decisive difference as to whether a new-build project is financially viable or not.
Who benefits most from the KFW interest rate cut?
Young families and builders
The KfW interest rate cut 2025 offers enormous advantages for young families who want to realize their dream of owning their own home or building a new climate-friendly home. The significantly lower interest conditions reduce the monthly burden and make it easier to buy or build a home.
Building owners in rural areas
In regions with lower property prices, there is often more budget for a high-quality, energy-efficient building. Here, builders can benefit in particular from favorable financing and at the same time invest in the best energy efficiency.
Climate-conscious building owners
Anyone who had already planned to build particularly energy-efficiently will now be doubly rewarded: with low energy costs during operation and extremely favorable financing conditions for new construction.
Property developers and investors
The new conditions are also highly attractive for property developers who want to construct climate-friendly new buildings. If there are several residential units, the subsidy amounts are multiplied accordingly – for an apartment building with 6 residential units, this amounts to up to 900,000 euros in favorable KfW loans.
Intergenerational houses
Up to EUR 300,000 (for two residential units) can be financed at the favorable conditions for the construction of two-family houses or houses with granny apartments.
The technical requirements for subsidies for climate-friendly new builds
What does Efficiency House 40 mean for new builds?
The Efficiency House 40 standard means that the newly constructed building only requires 40% of the primary energy of a reference building in accordance with the German Building Energy Act (GEG). In practice, this is achieved in a new building by:
Building envelope:
- High-quality thermal insulation of all exterior walls (U-value approx. 0.15 W/m²K)
- Insulation of the top storey ceiling or the roof (U-value approx. 0.14 W/m²K)
- Insulation of the floor slab or cellar (U-value approx. 0.20 W/m²K)
- Triple glazing in all windows (U-value approx. 0.80 W/m²K or better)
- Airtight construction with professional blower door test
Building services:
- Ventilation system with heat recovery (at least 80% heat recovery)
- Highly efficient heating technology, typically:
- Air-to-water heat pump with high seasonal performance factor (SPF > 4.0)
- Brine-to-water heat pump (geothermal) with SPF > 4.5
- Pellet heating with solar support
- Photovoltaic system for power generation (recommended, but not mandatory)
- Intelligent heating control and building automation
Energy concept: For a typical new-build detached house with 150 m² of living space, this means the Efficiency House 40 standard:
- Heating requirement: approx. 20-30 kWh/m²a
- Primary energy requirement: maximum 40% of the reference building
- Annual heating costs: approx. 300-600 euros (depending on energy price and usage)
The sustainability certification
In addition to the Efficiency House 40 standard, KfW also requires sustainability certification. This ensures that ecological and socio-cultural aspects are also taken into account in new construction:
Ecological quality:
- Use of sustainable, low-emission building materials
- Minimization of greenhouse gas emissions in the life cycle
- Conservation of resources and recyclability
- Protection of soil and groundwater
Socio-cultural quality:
- Accessibility or at least low accessibility
- Health and comfort (sound insulation, daylight, indoor air quality)
- User-friendliness and design quality
Recognized certifications for new construction:
- Quality seal for sustainable buildings (QNG)
- DGNB certificate (German Sustainable Building Council)
- BNB assessment system (Assessment System for Sustainable Building)
Costs of certification: Expect to pay an additional 3,000 to 6,000 euros for the sustainability certification of a new single-family home.
Political context and outlook for the KFW interest rate cut in 2025
Background to the KfW interest rate reduction for climate-friendly new builds
The KfW interest rate reduction is part of the political strategy to boost the climate-friendly construction of new residential buildings. After years of rising construction costs and high interest rates, KfW Bank is responding in cooperation with the Federal Ministry of Construction with a significant reduction in promotional interest rates.
This is intended to make the KfW funding programs for new construction and home ownership more attractive again and strengthen the construction industry. The aim is to create more energy-efficient residential buildings and at the same time achieve the climate targets in the building sector.
Significance for developers and owners
For builders, families and investors, the KfW interest rate change means a real new start in the housing sector. The low effective annual interest rates make investments in climate-friendly residential buildings, efficiency houses and sustainable construction profitable again.
The combination of KfW funding, repayment subsidy and possible state funding programs also significantly improves the framework conditions.
Planned extensions to the KfW promotional programs
For 2025, the German government is planning additional measures in the area of KfW new construction programs:
- Re-introduction of subsidies for new Efficiency House 55 buildings
- Increase in the maximum subsidy amounts per residential unit
- Simplification of the application process for KfW loans
These steps are intended to make construction subsidies even more efficient and create more living space through climate-friendly new builds.
Step by step to KfW funding for new builds
Phase 1: Preliminary planning and energy consultant by us
You need an energy efficiency expert before you start building a new home. This expert should be involved in the early planning phase in order to:
- Developing the optimum energy concept for your new-build purchase
- Ensuring compliance with the Efficiency House 40 standard
- Preparing for sustainability certification
- Create a “confirmation of application” (BzA)
Important: The expert must be registered in the energy efficiency expert list for federal funding programs (www.energie-effizienz-experten.de).
Costs for the new build: Expect to pay between 2,000 and 4,000 euros for specialist energy planning and construction supervision. These costs can be subsidized with up to 50% (maximum 5,000 euros) via the KfW 431 program!
Phase 2: Application before the start of construction
KfW funding is not applied for directly from KfW, but via your house bank using the pass-through procedure.
Critical time: The application must be submitted BEFORE the building contract is concluded!
The start of the project is:
- Conclusion of a building contract
- Conclusion of a contract with a prefabricated house supplier
- Start of construction work
NO project start yet:
- Purchase of land
- Architect’s contract for the planning
- Structural engineers and engineering services
- Building application
Tip: You can take your time to plan, buy the plot and submit the building application before you have to apply for the KfW subsidy.
Phase 3: Loan commitment and interest reservation
After your application has been reviewed, you will receive a loan approval from KfW from your house bank.
Important for reserving interest rates: Most banks offer to reserve the current KfW interest rates for up to 10 bank working days. As interest rates can change on each trading day, you should:
- Choosing the right time to apply
- Act quickly with favorable interest rates
- Use the interest reservation
Phase 4: New construction and call for funds
During the construction phase of your new build, KfW funds are drawn down as construction progresses. Your energy efficiency expert accompanies the construction and checks compliance with all requirements.
Phase 5: Completion and “confirmation after implementation”
After completion of the new building, your energy efficiency expert must issue a “Confirmation after implementation” (BnD). This proves that:
- The Efficiency House 40 standard was achieved
- All technical requirements are met
- The sustainability certification is available
Only with this BnD is the funding finally secured!
Avoid common mistakes in new builds
Mistake 1: Applying too late
By far the most common mistake: The KfW application is only submitted after the building contract has already been signed. This leads to automatic rejection of the funding!
Correct: Submit application → Wait for loan approval → Sign building contract
Mistake 2: Forgetting sustainability certification
Many builders only focus on the Efficiency House 40 standard and forget about sustainability certification. However, this must be included in the planning right from the start!
Right: Work with a QNG auditor as early as the planning stage
Mistake 3: Wrong or unauthorized energy consultant
Not every energy consultant is approved for KfW funding. Only experts from the official list of energy efficiency experts are authorized to issue the required certificates.
Correct: Check the entry in the list before commissioning
Error 4: Requirements not met during construction
Sometimes changes are made during the new build that fall short of the originally planned efficiency house standards (cheaper windows, less insulation, etc.).
Consequence: The subsidy must be repaid!
Right: Coordinate every change with the energy consultant
Error 5: No quality assurance during construction
Without continuous monitoring by the energy efficiency expert, construction errors can occur that jeopardize the achievement of the Efficiency House 40 standard.
Right: Involve energy consultants regularly on the construction site
Combination with other subsidies for new construction
State funding programs
Many federal states offer their own funding programs specifically for new builds. These can often be combined with the KfW program:
- Bavaria: BayernHeim home ownership promotion
- Baden-Württemberg: Housing BW
- North Rhine-Westphalia: NRW.BANK Housing
- Saxony: SAB funding for home ownership
Tip: Ask your state development bank about additional options specifically for new buildings.
Housing construction premium
You can use the housing construction premium as additional equity for your new home. It amounts to 10% of up to 700 euros (single persons) or 1,400 euros (married persons) in annual savings.
Photovoltaic promotion
If you install a PV system on your new building, in addition to the KfW subsidy for the building, you can also:
- Use KfW loan 270 for the PV system (also on favorable terms)
- Receive feed-in tariff according to EEG
- Use regional PV subsidy programs
Important: The subsidies for the building (KfW 297/298) and the PV system (KfW 270) can be combined!
KfW Home Ownership Program 124 – additional financing for homeowners
In addition to the KfW 297/298 program (climate-friendly new construction of residential buildings), KfW Bank offers another attractive subsidy for builders and owners in the form of home ownership program 124.
The KfW Home Ownership Program (No. 124) is aimed at private individuals who want to buy or build their own home or condominium and use it themselves.
The promotional loan can amount to up to EUR 100,000 per project and is not tied to efficiency house standards. This makes it ideal for supplementing the KfW promotional loan 297/298, for example to finance land costs or personal contributions.
The following also applies here: The application is made via the house bank, with a freely selectable fixed interest rate and redemption-free start-up period.
By combining several KfW funding programs (e.g. 124 + 297/298), particularly favourable financing conditions can be achieved for climate-friendly new buildings and residential property.
Practical tips for your new build with KfW funding
Tip 1: Talk to the bank early
Make an appointment with your bank during the planning phase. Clarify:
- Whether the bank passes on KfW loans
- Which documents are required
- What the exact procedure is
- Whether a combination with a home loan is possible
Tip 2: Obtain several offers
Even if the KfW interest rate is fixed, the banks can offer different conditions for:
- Offer the supplementary home loan
- Charge processing fees
- Calculate commitment interest
Tip 3: Allow for buffer time
It can take 4-6 weeks from application to loan approval. Plan for this time and set realistic deadlines in the building contract.
Tip 4: Quality before price from the energy consultant
A good energy efficiency expert will save you more money than he costs:
- Optimized energy concept = lower construction costs
- Professional construction supervision = no expensive reworking
- Safe achievement of the standard = safe promotion
Tip 5: Documentation from day one
Photograph all relevant construction phases:
- Laying the insulation
- Installation of the building services
- Airtight level
- Window installation
This documentation can be very helpful in the event of problems or queries from KfW.
How interest rates are developing: Outlook
KfW regularly adjusts its interest rates in line with market developments. The current top conditions of 1.13% are also a political decision and reflect the willingness of the federal government to subsidize new construction.
Important to know:
- Interest rates are adjusted every trading day
- Political decisions can influence interest rates
- When capital market interest rates rise, KfW interest rates also rise
- The interest rates quoted are as at September/October 2025
Political perspective: In view of the climate targets in the building sector and the acute housing shortage, it can be assumed that the federal government will keep the programs attractive in the medium term. However, the framework conditions can change with every budget negotiation.
Our advice: If you are planning a new build and the current interest rates are suitable, you should take action as soon as possible. Take advantage of the interest rate reservation option!
Our conclusion: Ideal time for climate-friendly new builds
The current reduction in interest rates makes climate-friendly new builds more attractive than they have been for a long time. The interest rate advantage of up to three percentage points compared to market interest rates means savings of over 13,000 euros over ten years for a subsidy amount of 100,000 euros.
The most important arguments for a KfW-subsidized new build now:
- Financial benefits: Over 13,000 euros in savings with 100,000 euros in funding
- Low monthly charge: 131 euros less per month than with market interest rates
- Future-proof: Efficiency House 40 means minimal energy costs
- Stable value: energy-efficient new builds retain their value better
- Climate protection: you make an important contribution to CO2 reduction
Concrete next steps:
- This week: Make an appointment with your bank
- Next week: Find and contact energy efficiency experts
- Next 4 weeks: Have energy concept drawn up and finalize construction planning
- Before the building contract: submit a KfW application and receive a loan commitment
- After approval: sign construction contract and start new build
With the current KfW conditions, you not only build in a climate-friendly and future-proof way, but also save considerably on financing. Your new build as an Efficiency House 40 will save you money in the long term thanks to minimal energy costs and is also good for the environment.
Start now: The path to your own climate-friendly new build has not been as financially attractive as it is today for a long time. The combination of low KfW interest rates, high energy efficiency and long-term savings on energy costs makes your new build a smart investment!
As at: October 2025 The interest rates quoted may change daily. You can find current conditions directly from KfW or your bank. All information without guarantee. Get individual advice on your new construction project.