Renovation to Effizienzhaus with the KfW loan 261
When an existing building is renovated as a whole to reach an Effizienzhaus level, KfW supports it with a low-interest loan and a repayment bonus (Tilgungszuschuss). We carry out the construction work.
What KfW funds in an Effizienzhaus renovation
The Bundesförderung für effiziente Gebäude (BEG, the federal funding scheme for efficient buildings) supports the renovation of an existing building to an Effizienzhaus level through a low-interest loan from the KfW, Germany's state development bank. Unlike single-measure funding it looks at the building as a whole: roof, external walls, basement ceiling, windows, building services and airtightness together produce the calculated energy demand that determines the Effizienzhaus level. The better the level achieved, the higher the Tilgungszuschuss — the share of the loan you do not have to repay. You apply through your own bank before work begins; planning and verification are handled by an independent energy efficiency expert from the federal expert register. For us as a timber construction company the route is interesting when larger works are due anyway: a storey extension, a new roof, an insulated envelope or a full interior fit-out. Such works can be bundled into one package that lifts energy quality in a single step.
Who this route suits
The loan is aimed at owners of residential buildings whose energy performance is well below today's standard — typically detached and semi-detached houses built between 1950 and 1990 with an uninsulated roof, thin wall insulation and outdated building services. Inherited houses and purchased properties with a renovation backlog belong here too. Private individuals, owners' associations, landlords and companies are all eligible to apply. The route makes sense if you are tackling several trades at once and want to improve the building as a whole — not if only a single component is being replaced.
What we build within such a package
From our range of services, the following fit an Effizienzhaus renovation: a storey extension in timber frame construction where additional living space is wanted; an insulated building envelope as a prefabricated timber layer in front of or added onto the existing wall; roof renewal with insulation between and above the rafters, sub-roof membrane and new roof covering; a continuous airtightness and vapour control layer; and drywall work in the interior fit-out. We also carry out supporting solid construction work. Windows, heating technology and electrical installation are not our trades — these works are contracted separately.
Requirements at a glance
The property must be an existing residential building; as a rule the building application or notification dates back at least five years.
An independent specialist from the federal register of energy efficiency experts plans the measure, issues the confirmation of application and verifies the level achieved.
The application is submitted through your bank before work begins — that is, before supply or service contracts are firmly concluded.
After renovation the building must demonstrably reach an eligible Effizienzhaus level; individual components alone are not sufficient for this programme.
The technical minimum requirements must be met: component build-ups, thermal bridges, airtightness, moisture protection and a ventilation concept.
No double funding: for the same measure neither the tax reduction under § 35c EStG nor a BAFA grant can be claimed in addition.
The process in five steps
Survey and definition of the target
We inspect the building, survey the roof, external walls and connection details and clarify which construction works are technically sensible and structurally feasible. This shows whether an Effizienzhaus level can realistically be reached.
Bring in the energy efficiency expert
An independent specialist from the federal expert register calculates the building, defines the target level and issues the confirmation of application. Without this confirmation no funding application is possible.
Apply through your own bank
With the confirmation of application you apply for the loan at your bank — before work begins. Only once approval is granted are the construction contracts firmly concluded and the works scheduled.
Carrying out the construction work
We build the agreed trades: storey extension, insulated timber frame envelope, roof build-up with new covering, airtightness layer and drywall — in line with the technical minimum requirements of the programme.
Verification and repayment bonus
After completion the specialist confirms the Effizienzhaus level achieved. KfW credits the repayment bonus against the loan, so the amount you actually have to pay back is reduced accordingly.
Why timber construction fits this kind of renovation
Timber frame construction offers three structural advantages in energy retrofits. First, the insulation sits between the studs rather than in front of the structure: for the same thermal performance the build-up stays slimmer, which saves space at the eaves and connections. Second, timber structures are light — with a storey extension the dead load decides whether the existing structure can carry it. Third, wall and roof elements are prefabricated and assembled within a few days, keeping the period with an open roof short. Decisive for durability is moisture protection: the build-up needs a continuous airtightness and vapour control layer and must be tighter inside than outside so that moisture can dry out.
Services we carry out for this
We carry out the construction work. Evidence and applications go through independent experts.
Our role — and what we do not do
MAIER & PARTNER INNOVATIVBAU is a construction company, not an energy consultancy and not an application office. We plan and build the structure: surveying, detailed design of the component build-ups, coordination of the structural analysis, execution and documentation. The energy calculation and the confirmations for KfW must come from an independent specialist in the federal expert register — this is required by the programme and would not be neutral coming from us. We coordinate our build-ups with that specialist, supply the data needed for verification and document materials and insulation thicknesses.
Source: kfw.de – Wohngebäude loan 261Frequently asked questions about funding
How high is the repayment bonus for a renovation to Effizienzhaus?
The Tilgungszuschuss depends on the Effizienzhaus level achieved and was revised when the BEG was adjusted on 21 July 2026. On top of that come bonuses for particularly poor existing buildings and for serial renovation. Only the current KfW information sheets are binding — have the exact figure checked by your energy efficiency expert before you decide.
Do I really need an accredited energy efficiency expert?
Yes. Without a specialist from the federal register of experts for funding programmes neither the application nor the later crediting of the repayment bonus is possible. The expert issues the confirmation of application, accompanies the construction work and confirms the level achieved after completion. These costs are generally eligible for funding.
Does a storey extension count as renovation or as new build?
There is no blanket answer. If existing space is converted or a storey is added without creating a separate new residential unit, this is usually attributed to the existing building. If, however, additional living space is created as a self-contained unit, new-build funding may apply instead. The energy efficiency expert decides this for your specific project.
Is the Effizienzhaus renovation also available as a pure grant?
For renovation to Effizienzhaus level KfW provides the loan route: you receive a low-interest loan through your own bank, and the funding share is credited as a repayment bonus against the outstanding balance. Direct grants without a loan are available from the BAFA for single measures on the building envelope. For one and the same measure the two routes cannot be combined.
Have your Effizienzhaus renovation assessed
Send us the year of construction, the floor plans and your goal. We will tell you which works on roof, envelope and storey extension are feasible and where the energy efficiency expert can pick up.
Status: July 2026. The federal funding scheme for efficient buildings was adjusted on 21 July 2026. All information without guarantee — only the current KfW information sheets and conditions are binding.
All information on funding programmes is provided to the best of our knowledge, without guarantee and without any claim to completeness. It does not replace legal, tax or energy consulting. Terms and budgets change constantly; only KfW, BAFA, NBank and the responsible funding bodies are binding. Applications must generally be filed before work begins.