🏗️ In brief: A full renovation achieves 70–85% energy savings and qualifies for the KfW Efficiency House standard with up to €150,000 in low-interest loans. Individual measures reduce consumption by 15–30% per step but are more flexibly financed. An iSFP can meaningfully connect both approaches.
The Fundamental Question of Every Renovation
Anyone looking to modernize their home’s energy performance will eventually face this decision: Should everything be renovated at once — or is it better to implement individual measures one at a time? Both paths have clear advantages and typical pitfalls.
The answer depends on several factors: your building’s condition, your budget, your energy goals, and your personal situation. In practice, there is no universal “right” or “wrong” — but there is an optimal strategy for every building.
This article compares both approaches honestly and practically — with concrete figures on costs, subsidies, and savings.
What Does a Full Renovation Mean?
In a full renovation, all energy-relevant building components are modernized in one coordinated project: exterior wall insulation, roof insulation, basement ceiling, windows, heating system, and often a ventilation system with heat recovery. The goal is a defined Efficiency House standard — such as Efficiency House 70 or 85.
The major advantage: all measures are coordinated with each other. The insulation matches the new heating, the windows match the ventilation. This prevents energy gaps and construction damage from incorrect sequencing.
Typical Costs: Single-Family Home
Investment volume: approx. €80,000–150,000
Construction time: 3–6 months (depending on scope)
Result: Efficiency House standard (EH 70, EH 85, or better)
What Are Individual Measures?
The alternative approach: you renovate your building step by step. First the windows, next year the insulation, then the heating. Each measure is planned, subsidized, and implemented individually — prioritized by the greatest savings potential.
This path is especially attractive for owners who want to spread their budget over several years or continue living in the house during renovation. The annual burden is significantly lower, and each measure shows immediate results on the heating bill.
Typical Costs per Measure
Window replacement: approx. €8,000–18,000
Roof insulation: approx. €15,000–30,000
Heating replacement (heat pump): approx. €20,000–35,000
Exterior wall insulation (ETICS): approx. €20,000–40,000
Costs and Subsidies Compared
The subsidy landscape differs significantly depending on the renovation path. Here are the two programs in direct comparison:
Full Renovation: KfW 261
Low-interest loan: up to €150,000 per residential unit
Repayment grant: 5–45% (depending on Efficiency House standard achieved)
EE or NH class: additional 5% repayment grant
Advantage: Higher total subsidy, better cost-benefit ratio per invested euro
Individual Measures: BEG EM
Direct grant: 15–70% of eligible costs
Eligible costs: max. €30,000 per unit (€60,000 with iSFP)
Heating replacement: separate subsidy rates, max. €19,600 grant (since the July 2026 BEG reform)
Advantage: Lower entry barrier, immediate grant instead of loan
Important: The subsidy programs cannot be combined freely. Those using the KfW 261 loan for a full renovation cannot apply for BEG EM grants for the same measures. Careful planning with your energy consultant is therefore essential.
Energy Savings: The Decisive Difference
This is where the biggest difference between the two paths shows. A coordinated full renovation achieves savings of 70–85% compared to the unrenovated state. The building then meets a defined Efficiency House standard — such as EH 70 or EH 85.
Individual measures typically bring 15–30% savings per step. Combined over several years, a total level of 50–60% can be achieved — but without the synergy effect of a coordinated renovation.
Full Renovation
Savings: 70–85%
Target: EH 70 / EH 85
Synergy effects: Yes
Optimal overall result
Individual Measures
Savings: 15–30% per step
Total over years: 50–60%
Synergy effects: Limited
Immediately noticeable improvement
The reason for the difference: in a full renovation, all components are coordinated. A new heat pump can be sized smaller when the envelope is well insulated. Ventilation prevents moisture damage despite an airtight building envelope. These synergies are absent in step-by-step renovation.
When a Full Renovation Makes Sense
A full renovation doesn’t make sense in every case — but when the conditions are right, it’s the significantly more efficient path. Typical situations:
Building in Poor Energy Condition
When roof, facade, windows, and heating are all outdated simultaneously, a coordinated full renovation is more economical than five separate construction sites over ten years.
Efficiency House Standard as Target
You can only achieve the KfW Efficiency House standard with a full renovation. This secures you the KfW 261 loan with repayment grant — and a significantly higher property value.
Sufficient Budget or Financing
With the KfW 261 loan (up to €150,000 at attractive terms), a full renovation can be financed even without high equity. The repayment grant significantly reduces the repayment amount.
Major Life Event: Purchase, Inheritance, Move-Out
Those who buy, inherit, or renovate a house after children move out often have the ideal opportunity: the building is empty anyway or being fundamentally redesigned. The renovation can be perfectly integrated.
When Individual Measures Are the Better Choice
For many homeowners, the step-by-step approach is the more realistic option. This is not a disadvantage — as long as the measures are planned wisely:
Limited Budget
Not everyone can or wants to invest €80,000–150,000 at once. Individual measures allow distribution over years — with direct grants instead of loan obligations.
Building Is Partially Renovated
If new windows or a new roof are already in place, you don’t need a full renovation. Targeted individual measures sensibly complement what’s already there.
Living in During Renovation
A full renovation often means months of construction. Those who stay in the house prefer shorter, plannable individual measures — one trade at a time, then peace.
Step-by-Step Renovation with iSFP
With an individual renovation roadmap (iSFP), even individual measures are strategically planned. Each measure builds on the previous one — and you secure the 5% iSFP bonus.
The iSFP as a Bridge Between Both Paths
In practice, it doesn’t have to be either/or. The individual renovation roadmap (iSFP) combines the advantages of both approaches: it gives you an overall plan with Efficiency House perspective — which you can still implement step by step.
The consultant analyzes your building, defines a long-term goal, and creates a prioritized roadmap over 15 years. Each individual measure is planned so it doesn’t interfere with later steps.
Advantages of the iSFP for Individual Measures
5% additional funding on every individual measure under BEG
Doubling of eligible costs from €30,000 to €60,000 per residential unit
Clear prioritization: which measure first, which can wait?
Avoidance of planning errors: e.g., heating before insulation = oversized
Long-term Efficiency House goal remains achievable — even with step-by-step implementation
💡 Practical tip: Always have an iSFP created first before deciding between full renovation or individual measures. The roadmap shows you which path is the better choice for your specific building — and how to secure maximum subsidies.
Note: All figures on subsidy rates, costs, and savings potentials are as of August 2026 and serve as guidance. Changes by the legislator are possible at any time. This article does not replace individual energy consulting.
Which Renovation Path Suits Your Home?
As a certified energy consultant, we analyze your building, compare both options, and create your individual renovation roadmap — including subsidy optimization.