Energy consultants for window subsidies: When is a consultation mandatory?
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Who is an energy consultant and why will they be important for window subsidies in 2026?
An energy consultant is a certified energy efficiency expert who assesses the energy efficiency of buildings and provides technical support for renovation measures. If you want to install new windows in 2026 and take advantage of subsidies, they will play a key role. Many subsidy programs require technical documentation and formal steps that are difficult to implement without professional support. The energy consultant ensures that your window replacement is planned and implemented in accordance with subsidy requirements, is familiar with the current requirements of BAFA, KfW, and tax subsidies, and takes care of the necessary applications and confirmations—so that grants and loans are actually paid out.
When is an energy consultant mandatory – and when is it voluntary?
In order to take advantage of the appropriate subsidy, it is crucial to know when an energy consultant is mandatory – and when their services are voluntary but still recommended.
An energy consultant is mandatory in the following cases:
BAFA subsidy and mandatory energy consulting for BEG EM
KfW subsidy and role of the energy efficiency expert
In the following cases, an energy consultant is voluntary:
Tax subsidy according to § 35c EStG – also possible without EEE
Mandatory requirement – BAFA subsidy and energy consultation for BEG EM
For individual measures within the scope of the Federal Subsidy for Efficient Buildings – Individual Measures (BEG EM), such as replacing old windows or insulation measures, an energy consultation is mandatory. The involvement of an energy efficiency expert ensures that the planned measures are implemented in accordance with the subsidy requirements and that all necessary evidence is provided correctly. Without this professional support, funding under the BEG EM is not possible.
The most important framework conditions and requirements at a glance:
Window replacement is funded through the BEG individual measures (BAFA).
The subsidy amounts to 15 percent, with an additional iSFP bonus of 5 percent, up to 20 percent is possible.
An energy efficiency expert (EEE) from the dena list of experts must be involved.
The EEE prepares the funding application, the technical project description (TPB), and the confirmation after implementation (BnD).
Without the involvement of an EEE, the funding application will not be approved.
Mandatory requirement – KfW funding and the role of the energy efficiency expert
KfW funding programs also require the involvement of an energy consultant if energy requirements must be verified and funding conditions met. Energy efficiency experts play a key role in ensuring eligibility for funding and providing technical support throughout the entire process, particularly in the case of more extensive renovation projects.
The most important requirements and special features of KfW funding at a glance:
Individual windows are no longer eligible for isolated funding from KfW.
Window measures are only eligible for funding as part of a renovation to create an energy-efficient house.
Funding is provided via KfW loan 261 with a repayment subsidy.
An energy efficiency expert (EEE) must be involved in the application and construction supervision.
The loan will not be approved without the involvement of an EEE.
Voluntary – tax relief under Section 35c of the German Income Tax Act (EStG)
Tax relief under Section 35c EStG is aimed at owner-occupied residential properties and represents an alternative to traditional subsidy programs. Unlike BAFA and KfW subsidies, there is no mandatory energy consultation requirement. Nevertheless, the responsibility for correct implementation and documentation remains entirely with the owner.
The most important requirements and conditions for tax incentives at a glance:
The incentive is provided via Section 35c EStG as part of income tax.
Twenty percent of the costs can be claimed for tax purposes over three years.
An energy efficiency expert (EEE) is not mandatory.
The minimum technical requirements (e.g., the Uw value for windows) must be met.
Implementation must be clearly documented by means of invoices from tradespeople.
What specific tasks does an energy consultant perform?
An energy consultant performs a number of key tasks to ensure that you can apply for subsidies and that energy efficiency measures are implemented correctly. They support your project from the initial analysis to the final verification by BAFA, KfW, or the tax office.
Individual renovation roadmap (iSFP)
The individual renovation roadmap provides structured, long-term guidance for the energy-efficient modernization of your windows or building. It shows which measures make sense, how they build on each other, and what efficiency potential they offer. If the iSFP is created before individual measures such as window replacement, the subsidy rate increases by an additional 5 percentage points.
Energy assessment and building analysis
First, the energy consultant evaluates the current energy status of the property. This analysis forms the basis for all further recommendations and evidence:
Recording of year of construction, construction method, and insulation standard
Analysis of windows, building envelope, and heat loss
Evaluation of existing heating and ventilation technology
Technical inspection and expert confirmation
The energy consultant checks whether the planned measures meet the technical subsidy requirements and confirms this to the funding agencies:
Checking the U-values and energy performance indicators
Checking product data sheets and technical documentation
Confirming the energy benefits of the measure
Providing expert support for proper implementation
Subsidy application and formal processing
One of the key tasks of the energy efficiency expert is to ensure that subsidy applications are completed and processed correctly. Without this professional support, many subsidy programs are not accessible:
Preparation and submission of the subsidy application
Preparation of the technical project description (TPB)
Coordination with BAFA or KfW during the ongoing process
Construction supervision and quality assurance
During implementation, the energy consultant ensures that the measures are carried out as planned and in accordance with the subsidy requirements. This allows deviations to be identified and corrected at an early stage:
Technical support during the construction phase
Checking the execution for compliance with subsidy and quality requirements
Support with queries from tradespeople
Documentation after completion of the measures
After completion, the energy consultant takes care of the final documentation for the funding agency or tax office:
Preparation of the confirmation after implementation (BnD)
Compilation of all technical evidence and invoices
Ensuring payment of the subsidy or repayment subsidy
Support with tax incentives (§ 35c EStG)
Even though an energy consultant is not mandatory for tax incentives, they can provide advisory support to avoid losing out on subsidies:
Checking the minimum technical requirements
Support with correct invoicing and documentation
Determining whether § 35c EStG or a subsidy program makes more economic sense
How much does an energy consultant for windows cost and what funding options are available?
The cost of hiring an energy consultant varies depending on the scope of services, building size, and complexity of the project. While some consultations only provide an initial assessment, others include a detailed analysis with a renovation roadmap and support. In addition, government subsidy programs can significantly reduce the financial burden.
Typical costs for energy consulting services
The costs of energy consulting depend largely on the services required and how complex the analysis of the building is. Energy consulting including an individual renovation roadmap (iSFP) is particularly popular, as it provides a sound basis for decision-making on renovations. The following price ranges have become established for private owners:
The following cost items are decisive:
Energy consulting including iSFP (single-family home): typical total costs between $1,300 and $2,500
Energy consultation including iSFP (multi-family house): from around €2,550, depending on the number of residential units and the complexity of the building
Additional services: possible additional costs for construction supervision, heating load calculation, or energy performance certificates
BAFA subsidy for energy consultation
The costs of energy consulting can be significantly reduced through government subsidy programs. The central point of contact is the BAFA subsidy “Energy consulting for residential buildings,” which is specifically tailored to private owners. In particular, the creation of an individual renovation roadmap, which serves as the basis for further subsidy applications, is subsidized.
The following funding conditions apply to energy consulting:
Funding rate: 50 percent of eligible consulting costs
Maximum subsidy: 650 euros for single-family and two-family houses
Higher subsidy: 850 euros for residential buildings with three or more residential units
Prerequisite: Implementation by a certified energy efficiency expert (EEE) from the dena list of experts
Important: The subsidy application must be submitted before the consultation begins
Free energy consultants – when is this possible?
In certain cases, energy consulting can be offered free of charge or at a greatly reduced rate. However, these are usually initial consultations for guidance purposes only and do not replace eligible energy consultations. They are particularly suitable for an initial assessment or basic information.
It is important to note that these consultations are not usually eligible for funding under BAFA or KfW and do not replace an individual renovation roadmap or the mandatory consultation for funding applications.
Free or discounted offers are available, among others:
through consumer centers, usually as initial or brief consultations
through local authorities or regional energy agencies, often for a limited period
as part of pilot projects or voucher campaigns, depending on the region and budget
How to find a qualified energy consultant for windows
To ensure that the window replacement is carried out correctly from a technical point of view and that you don't miss out on any subsidies, you should take a structured approach to selecting an energy consultant. The following steps will help you find a qualified and eligible contact person.
Step 1 – Select a certified energy efficiency expert
The most important step is to select an energy consultant who is officially approved for subsidy programs. Only certified energy efficiency experts (EEE) are permitted to assist with subsidy applications to BAFA or KfW and issue the necessary documentation. You can search for one using the dena list of experts, which includes all approved specialists.
Step 2 – Check their experience with window replacement and individual measures
Not every energy consultant automatically specializes in windows. You should therefore check whether the consultant regularly assists with individual measures such as window replacement and is familiar with the relevant requirements, such as Uw values, connection details, or the evaluation of thermal bridges.
Step 3 – Ensure independence and neutral advice
A qualified energy consultant works independently of manufacturers and tradespeople. They do not recommend specific products or companies, but evaluate measures solely on the basis of their energy efficiency, eligibility for subsidies, and cost-effectiveness. This protects against recommendations based on vested interests.
Step 4 – Clarify the scope of services and subsidy processing
Before commissioning, it should be clear which services the energy consultant will provide. In the case of window replacement, this includes, in particular, the technical project description (TPB), confirmation after completion (BnD), and support with the subsidy application. Clear coordination prevents later.
Step 5 – Involve an energy consultant at an early stage
The energy consultant must be involved before the window company is commissioned. This is the only way to ensure that the measure remains eligible for funding. Involving the consultant too late may result in subsidies or loans no longer being granted.
The energy consultant needs the following documents for your subsidy application
Various technical and organizational documents are required to apply for subsidies from BAFA or KfW. The more complete the information provided, the smoother the energy consultant can prepare and implement the subsidy application:
Year of construction and building type: single-family house, two-family house, or multi-family house, including any extensions
Floor plans and sections: ideally with dimensions, alternatively sketches or existing construction plans
Photos of the current condition: windows, reveals, roller shutter boxes, and relevant facade areas
Energy consumption values: Heating bills or energy consumption for the last one to three years
Quotes from specialist companies: detailed service descriptions for the planned window replacement
Product data for the planned windows: technical data sheets with information on the Uw value, glazing, and frame
Information on the installation situation: type of window replacement, connection details, and special structural conditions
Proof of ownership: extract from the land register or comparable proof, depending on the subsidy program
Bank details: required for the payment of subsidies
TPB ID and TPN ID: relevant for BAFA applications within the framework of BEG individual measures
Power of attorney for the energy consultant: necessary if the application is made on behalf of another person
Common mistakes in grant applications and how to avoid them
When applying for grants for energy efficiency measures, many projects fail not because of the measure itself, but because of formal or technical errors. These often lead to queries, delays, or complete rejection of the grant:
Applying after the measure has begun: Grant applications must always be submitted to the contractor before the order is placed. Measures that have already begun are not eligible for funding.
Missing or incorrect confirmations: Technical project descriptions (TPB) or confirmations after completion (BnD) are missing, incomplete, or incorrectly filled out.
Incomplete technical documentation: Quotes, product data sheets, or implementation descriptions are insufficient or do not meet the funding requirements.
Missing U-value certificates: The energy performance values of the windows, in particular the Uw value, are not clearly documented or do not comply with the funding requirements.
Non-compliance with minimum standards: The minimum technical requirements of the BEG guidelines are not met, for example due to incorrect product selection or poor execution.
Incorrect subsidy combinations: Grants, loans, or tax incentives are combined in an impermissible manner.
Late involvement of the energy consultant: The energy efficiency expert is only involved after the offer has been accepted or construction has begun, which means that eligibility for subsidies is lost.
Tip: Have your funding application checked thoroughly by an energy efficiency expert (EEE) before submitting it. This will help you avoid formal errors and significantly reduce the risk of rejection.