⚡ In brief: Subsidy programs can often be combined — but not always. The key rule: BEG grants and the tax bonus (§35c) cannot be claimed simultaneously for the same measure. However, different measures can be funded through different programs. Public funding is capped at 60% of eligible costs.
Subsidies Are Good — the Right Combination Is Better
Many homeowners leave real money on the table during renovation — not because they don't apply for subsidies, but because they don't optimally combine the various programs. Those who only apply for a BAFA grant but forget the KfW supplementary loan, state funding, or iSFP bonus can easily miss out on 5,000 to 15,000 euros.
The subsidy system in Germany is complex: federal, state, and municipal governments each offer their own programs. Some can be combined without issues, others are mutually exclusive. And there's an important upper limit when combining.
In this article, we show you which programs exist, what can be combined — and how you as a homeowner can secure the maximum funding for your renovation.
The Most Important Subsidy Programs at a Glance
BEG Individual Measures (BAFA)
Grants for individual renovation measures on the building envelope: insulation, windows, sun protection, ventilation systems. Subsidy rate: 15% (+5% iSFP bonus). Eligible costs: up to €30,000 per residential unit (with iSFP: €60,000). Administered by: BAFA.
BEG Individual Measures — Heating Replacement (KfW 458)
Grant for replacing fossil heating with heat pumps, biomass, or solar thermal. Base rate: 30%. Additional bonuses available: climate speed bonus (+16%), income bonus (up to +40%). Maximum 70% subsidy, capped at €28,000 eligible costs (1st residential unit). Administered by: KfW.
KfW Efficiency House (KfW 261)
Low-interest loan with repayment subsidy for complete renovation to efficiency house standard (EH 40, 55, 70, 85). Loan amount up to €150,000 per unit (RE class). Repayment subsidy depending on efficiency level: 5–45%. Administered by: KfW via your bank.
KfW Supplementary Loan (358/359)
Low-interest supplementary loan for anyone who has already received a BEG grant. Up to €120,000 per unit. Particularly attractive for household incomes under €90,000/year (additional interest reduction). Administered by: KfW via your bank.
Tax Bonus §35c EStG
Alternative to BEG: Tax deductibility of energy renovation measures on owner-occupied homes. 20% of costs (max. €40,000 per property), spread over 3 years. No application needed — settled via tax return. Requirement: building at least 10 years old, contractor certification.
State Funding NRW (progres.nrw)
Supplementary state funding in North Rhine-Westphalia for various measures such as ventilation systems, battery storage, charging points, and consulting services. Combination with BEG generally possible (observe cumulation limit). Administered by: District Government Arnsberg.
Municipal Programs
Many cities and municipalities offer their own subsidy programs — for example for green roofs, photovoltaics, or rainwater harvesting. Availability and conditions vary greatly. Tip: Ask at your town hall or climate protection manager.
What Can Be Combined?
Here are the most important combination rules at a glance. The decisive question is always: Is it the same measure or different measures on the same building?
| Combination | Same Measure | Note |
|---|---|---|
| BEG + KfW-Ergänzungskredit | ✓ | Loan supplements the grant |
| BEG + § 35c Steuerbonus | ✗ | Double funding excluded |
| BEG + Landesförderung | ✓ | Observe 60% cumulation limit |
| BEG + kommunale Förderung | ✓ | Observe 60% cumulation limit |
| BEG EM + KfW 261 (Effizienzhaus) | ✗ | Either individual measures or efficiency house |
| § 35c + Landesförderung | ✓ | Generally possible |
💡 Important: For different measures on the same building, you can choose different funding paths. Example: Insulation via BEG EM (BAFA grant) and new windows via §35c (tax bonus) at the same time — this is allowed because they are two separate measures.
The Cumulation Rule: Maximum 60%
When you combine multiple public subsidy programs for the same measure, an important upper limit applies: Total public funding must not exceed 60% of eligible costs. If the limit is exceeded, the BEG grant is reduced accordingly.
This rule primarily affects the combination of BEG grants with state or municipal programs. The KfW supplementary loan does not count toward the cumulation limit, as it is classified as a loan — not a grant.
Calculation Example: Facade Insulation
€11,000 < €24,000 → The cumulation limit is not reached, both subsidies can be received in full.
Practical Example: Optimally Funding a Complete Renovation
The Schneider family owns a single-family home (built 1978) in the Siegerland region and plans a comprehensive energy renovation. Here's the optimal funding strategy:
Facade and Roof Insulation
Funding path: BEG EM (BAFA grant)
Eligible costs: €55,000
Subsidy rate: 20% (15% base + 5% iSFP bonus)
→ Grant: €11,000
Heating Replacement: Oil → Heat Pump
Funding path: BEG EM — Heating replacement (KfW 458)
Eligible costs: €28,000
Subsidy rate: 46% (30% base + 16% climate speed bonus)
→ Grant: €12,880
KfW Supplementary Loan
For the remaining personal costs (after deducting grants)
Loan amount: up to €120,000 at reduced interest rates
Household income < €90,000/year: additional interest reduction
→ Interest savings over term: approx. €8,000–12,000
NRW State Funding
Supplementary for ventilation system with heat recovery
progres.nrw grant: lump sum
→ Grant: approx. €1,500–3,000
Total Savings for the Schneider Family
→ Effective personal costs: approx. €59,000 instead of €95,000
Common Mistakes When Combining Subsidies
✗Application submitted too late
The BEG application must always be submitted BEFORE the work begins. Anyone who applies only after signing a contract (without suspensive condition) loses the claim entirely. With §35c it's different — here the settlement is done retroactively via the tax return.
✗Wrong order of applications
When combining BEG and state funding, the order is crucial. Typically, the federal application (BEG) must be submitted first, then the state application. Some state programs even require the BEG approval as a prerequisite.
✗Forgot the iSFP bonus
The iSFP bonus provides +5% more funding and doubles eligible costs from €30,000 to €60,000 per unit. Anyone planning individual measures should have an iSFP created first — the cost is itself subsidized at 50%.
✗Didn't check state funding
Many homeowners only think of BAFA and KfW and overlook state funding. In NRW, progres.nrw offers additional grants that can be easily combined with BEG — as long as the 60% limit is observed.
✗Applied for BEG and §35c for the same measure
This is the most common mistake: claiming both a BEG grant and the tax bonus for the same measure. This is explicitly not allowed. Choose the more favorable path per measure — with high subsidy rates (e.g., heating replacement at 50%), BEG is almost always better.
Why an Energy Consultant Makes the Difference
The subsidy system is complex — and it changes regularly. New guidelines, adjusted subsidy rates, expiring state programs: Even dedicated homeowners quickly lose track. A qualified energy consultant knows not only the individual programs but also how to optimally combine them.
In our practice, we regularly see that a well-thought-out funding strategy brings €5,000 to €15,000 more in subsidies than an uncoordinated individual application. The consulting costs typically pay for themselves through the iSFP bonus alone.
What We Do for You
✓ Check all subsidy programs (federal, state, municipal)
✓ Calculate optimal combination for your specific renovation
✓ Prepare applications in the correct order
✓ Create iSFP for maximum funding amount
✓ Monitor cumulation limit
✓ Prepare technical documentation for subsidy disbursement
Note: Subsidy rates, conditions, and combination rules are subject to change. The information listed here reflects the status as of August 2026. We recommend individual consultation for your specific project. This article does not constitute legally binding advice.
Maximum Funding for Your Renovation?
We analyze all available subsidy programs and calculate the optimal combination for your project — so no euro is left on the table.