Understand energy demand first.
Then refurbish with purpose.

RENOVATION GUIDE · 27 OCTOBER 2026

Plan insulation, windows and financing together.

Start with a target for the whole building. Compare heat losses, maintenance and financing before selecting individual products.

What needs to change?

Which U-values apply?

Lower U-values mean less heat transfer. The table covers selected statutory maximum values for specified alterations to ordinary residential buildings, in W/(m²·K). It is not a universal obligation to replace every existing component. Statutory minimum standards and grant requirements must be checked separately.

Special glazing, sliding doors, protected buildings, limited insulation depth and floor build-ups from the heated side can follow different rules. Insulation thickness depends on the material and existing assembly. A whole-building efficiency target may require better performance. Current BEG technical requirements must be verified before funding is planned.

Energy rating and efficiency-house standard

The A+ to H energy-certificate rating concerns final energy. A KfW efficiency-house assessment instead compares primary energy demand and transmission heat loss with a reference building. Rating B does not automatically mean efficiency house 55.

Efficiency house 55 example: at most 55% of the reference building’s primary energy demand and 70% of its transmission heat loss. Both criteria must be met; current EE/NH funding conditions also apply.

1. Collect plans, energy certificates, consumption data and previous renovation records.
2. Calculate coordinated variants for envelope, heating, hot water and ventilation.
3. Confirm the target through a whole-building assessment. Window replacement alone cannot guarantee a rating upgrade.
4. Coordinate connections and recalculate the heating load for the planned renovation.

An individual renovation roadmap helps sequence work; it does not replace funding or lending approval.

Can the entire renovation be financed?

Example only: six recognised units × €150,000 gives a theoretical ceiling of €900,000 under 261. Eligible costs of €750,000 fall below this ceiling; costs of €1,050,000 exceed it by at least €150,000. This arithmetic is not an eligibility or loan decision.

Separate eligible energy works and related costs from other modernisation. The financing partner checks creditworthiness, collateral and lending approval. Confirm application and contract rules before commissioning; the supplementary loan follows its own grant-first procedure.

What happened to the GEG reform?

Checked 27 October 2026: the German government states that the main provisions of the Buildings Modernisation Act (GModG) have applied since 29 July 2026, replacing the former GEG. This is an enacted change, distinct from further proposals. Component requirements, retrofit duties and exemptions still need project-specific review. The reform does not itself guarantee renovation finance.

Start with your building.

Bring the energy certificate, year of construction, unit count, plans, consumption and information on the envelope and heating. We structure the next steps with suitable specialists: survey, renovation options, energy target and financing.

Plan renovation and parking infrastructure together

The enacted GEIG amendments take effect on 1 January 2027. Project-specific requirements and transitional rules must be checked. Major renovations should include early planning for parking spaces, pre-cabling, cable routes and electrical infrastructure. This is not a universal retrofit obligation for every existing apartment building. Statutory duties and voluntary grant-eligible works require separate assessment.