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Which measures for energy-efficient building renovation are eligible for tax incentives?

The climate protection programme, with its expanded funding programmes, ensures that as many property owners as possible can invest in modernising their homes when needed. The following energy-efficient building renovation measures are supported under the climate protection programme:

  • Wall insulation
  • Roof insulation
  • Storey ceiling insulation
  • Renewal of windows or external doors
  • Renewal or installation of a ventilation system
  • Renewal of the heating system
  • Installation of digital systems for optimising energy operation and consumption
  • Optimisation of existing heating systems.

In addition, energy-related construction supervision and specialist planning are eligible for tax incentives.

Technical minimum requirements apply to these measures, which must be met for funding. For this reason, the tax reduction under § 35c can only be claimed if a corresponding certificate is submitted with the tax return. The certificate can be confirmed by a specialist company or an energy consultant (a person authorised to issue certificates under § 21 Energy Saving Ordinance).

Tip

Admittedly, when thinking of energy measures, one primarily considers insulation, the renewal of windows and external doors, or the renewal of the heating system. It is somewhat less known that since 2021, "summer heat protection" is also eligible for funding. This is somewhat hidden in Appendix 4a to the ESanMV.

It specifically states: "Funding is provided for the replacement or initial installation of external sun protection systems with optimised daylight provision, for example, through light guidance systems or radiation-dependent control. The requirements of DIN 4108-2:2013-02 for minimum summer heat protection must be met."

The "Second Ordinance Amending the Energy-Efficient Renovation Measures Ordinance" has transferred changes to the "Federal Funding for Efficient Buildings (BEG) - Individual Measures" to ensure the technical consistency of the funding. This includes the removal of funding for gas-powered heat pumps, gas condensing technology, and gas hybrid heating systems, as well as adjustments to building and heating network requirements. For biomass heating systems, the BEG changes to room heating efficiency and particulate matter are implemented.

This ordinance applies to measures from 31.12.2022.

Which measures for energy-efficient building renovation are eligible for tax incentives?



What is the funding amount for energy-efficient building renovation?

Tax incentives for energy-efficient renovation measures (§ 35c EStG)

Homeowners can claim a tax reduction under § 35c EStG for multiple individual energy-efficient measures, even if they are carried out independently of each other.

Amount of funding for energy-efficient renovation

For energy-efficient measures on owner-occupied property, 20% of the costs, up to a maximum of 40.000 Euro per property, are eligible for tax relief. The tax reduction is spread over three years:

  • Year 1 and 2: 7% of the costs each year, up to 14.000 Euro per year
  • Year 3: A further 6%, up to 12.000 Euro

The deduction is made directly from the tax liability, not from the taxable income.

Construction supervision and specialist planning: 50% deductible

For specialist energy planning and construction supervision by a certified energy consultant, 50% of the costs can be deducted from the tax liability.

You can find suitable experts at:
www.energie-effizienz-experten.de

Important conditions for the tax deduction (FG Hamburg, judgement of 06.08.2024, ref. 1 K 73/24)
  • The funding can only be granted if the taxpayer has a sufficient tax liability in each of the three funding years.
  • If the tax is less than the maximum deductible amount (e.g. under 14.000 Euro in the first year), the funding will be reduced accordingly.
  • An extension of the funding period beyond three years is not possible.

What is the funding amount for energy-efficient building renovation?



What conditions must be met in order to claim the tax reduction?

Requirements for tax reduction for energy-efficient measures under § 35c EStG

To claim the tax reduction for energy-efficient measures under § 35c EStG, certain conditions must be met:

  • Owner-occupation of the property: The property must be used for own residential purposes or provided free of charge to other persons.
  • Location of the property: The residential building must be located in Germany or within the EU or EEA.
  • Age of the property: At the start of the energy-efficient measure, the residential building or flat must be at least 10 years old.
  • Certificate according to the Energy Saving Ordinance (EnEV): A certificate according to § 21 EnEV from a specialist company or energy consultant must be available. This certificate is generally issued for the owner(s) of the property.
  • Invoice with correct details: You must have received an invoice containing the following details:
    • The eligible energy-efficient measures.
    • The labour of the specialist company.
    • The address of the eligible property.
  • Payment to the service provider's account: Payment must be made cashless to the service provider's account. Cash payments, cash deposits, partial cash payments or cash cheques are not eligible.
Special features and notes
  • Instalment payments: The Federal Fiscal Court has ruled that the tax reduction for energy-efficient measures can only be granted once the installation has been completed and the invoice amount has been fully paid into the installation company's account (BFH ruling of 13.08.2024, IX R 31/23).
  • Full payment of the invoice: The measure is only considered complete when the invoice is fully paid. Partial payments are not sufficient to claim the reduction in the respective tax year.
  • Combination with other tax reductions: If the tax reduction under § 35a para. 3 EStG (craftsman services) is claimed for the labour costs of an energy-efficient measure, additional funding under § 35c EStG is excluded.
Practical example

A couple had a new boiler installed in 2021. The total costs amounted to 8.000 Euro. The couple paid 200 Euro monthly in instalments. In 2021, only 2.000 Euro were paid. The tax office rejected the tax reduction because full payment would not be made until 2024. The tax reduction for energy-efficient measures can only be claimed with the final payment.

Conclusion

To receive the tax reduction under § 35c EStG, you must ensure that the invoice is fully paid and that all formal requirements, such as the issuance of a certificate and correct invoicing, are met. Make sure no cash payments are made, and plan the payment in the respective tax year accordingly to claim the reduction promptly.

What conditions must be met in order to claim the tax reduction?



Which companies can issue a specialist certificate?

A professional certificate can usually be issued by the company that carried out the energy efficiency measure. The prerequisite is that it operates in an approved trade according to the Energetic Renovation Measures Ordinance (ESanMV).

This includes companies from the following sectors:

  • Roofing, carpentry, joinery,
  • Painting, plastering, and thermal, cold, and sound insulation work,
  • Window, glass, metal construction, and sun protection work,
  • Heating, ventilation, sanitary, and electrical work,
  • Masonry, concrete, and other work on the building envelope.

Alternatively, the certificate can also be issued by a person authorised under § 88 GEG, such as a duly authorised energy consultant or energy efficiency expert.

Example: If a roofing company insulates your roof, this company can issue the professional certificate. If the measure is organised by a general contractor, the certificate is usually issued by the executing specialist company or a person authorised under § 88 GEG.

The certificate must be issued in the official format. Ask the specialist company before the work begins whether it will issue the certificate for the tax reduction under § 35c EStG.

Note: For measures starting in 2025, the BMF letter dated 23.12.2024 with the current certificate template applies. The general application questions regarding § 35c EStG are regulated by the updated BMF letter dated 21.08.2025.

Which companies can issue a specialist certificate?



What alternatives are there to tax incentives?

As an alternative to tax incentives, public building funding programmes can be used. These include, for example, low-interest loans or tax-free grants offered by the Kreditanstalt für Wiederaufbau (KfW Bank), the Federal Office for Economic Affairs and Export Control (BAFA), and state-owned development banks.

If you make use of one of these funding programmes, simultaneous tax incentives for the same energy renovation measure are not possible.

It is harmless if you have received grants solely for energy consulting. In this case, no tax reduction can be claimed for the costs of the energy consulting. However, for the energy measures carried out as a result of the energy consulting, for which no public funding was received, the tax reduction can be applied for.

What alternatives are there to tax incentives?



What applies to homeowners' associations?

If energy efficiency measures are carried out on a building consisting of several owner-occupied flats, a certificate must generally be issued for each individual flat. It is acceptable for the specialist company to issue a collective certificate for simplification purposes if the renovation expenses relate to the entire building or if the expenses attributable to the private property of individual flats can be clearly and unambiguously allocated to the individual flats.

If the owners' association has appointed a manager to handle its tasks and interests, the manager should be addressed as the client. In these cases, it is sufficient for the manager to allocate the expenses attributable to the co-ownership according to the ratio of the co-ownership share and inform the individual flat owner.

To do this, the manager creates a number of copies of the specialist company's certificate corresponding to the number of beneficiaries, on which they note the amount of expenses attributable to each beneficiary for the entire building and allocate the expenses attributable to the private property of individual flats to the specific flat owners.

What applies to homeowners' associations?

Field help

Executive specialist company

Enter the name of the specialist company that carried out the energy efficiency measure.

Example: If the company "Muster Dach GmbH" insulated your roof, enter this company name.

Start of the measure

Enter the start date of the energy efficiency measure.

  • For measures requiring approval: the date of the building application.
  • For measures with building documents to be submitted: the date of submission.
  • In all other cases: the actual start of on-site work.

Planning, consultation or signing a contract do not count as the start of the measure.

End of the measure

Enter the date on which the work was fully completed.

The tax reduction can be applied for the first time in the year in which the measure was completed and fully paid for.

Example: The work ends in September 2025. You state the costs in the tax return for 2025.

Thermal insulation of walls

Enter the costs for wall insulation.

Wall insulation involves the initial installation or renewal of external components of existing buildings and is eligible for tax incentives.

This includes:

  • Insulation of external walls,
  • Cavity wall insulation,
  • Insulation of external walls of listed buildings and buildings of historical interest,
  • Internal insulation of timber-framed external walls and renewal of infill,
  • Insulation of walls against unheated rooms,
  • Insulation of walls against the ground.
Thermal insulation of roof surfaces

Enter the costs for roof insulation.

Roof insulation is eligible for tax incentives when it involves the initial installation or renewal of external components of existing buildings.

This includes, for example, the insulation of

  • pitched roofs and associated collar beam layers,
  • dormer roof surfaces,
  • dormer cheeks,
  • flat roofs
Thermal insulation of ceilings

Enter the costs for insulating floor/ceiling structures.

The thermal insulation of floor/ceiling structures is eligible for tax incentives when it involves the initial installation, replacement, or renewal of external components of existing buildings.

This includes the insulation of

  • top floor ceilings to unconverted attics
  • cellar ceilings,
  • ceilings to unheated rooms
  • floor/ceiling structure downwards against outside air
  • floor surfaces against the ground
Renewal of windows / external doors

Enter the costs for new or energy-efficient windows, balcony and patio doors, and exterior doors.

Eligible items may include:

  • Windows with multi-pane insulating glass,
  • Roof windows,
  • Balcony and patio doors,
  • Exterior doors to heated rooms,
  • Energy efficiency improvements to existing windows,
  • Windows and doors in listed buildings or buildings of historical interest.

The initial installation may also be eligible. The technical minimum requirements must be met.

Installation or replacement for summer thermal protection

Enter the costs for external sun protection installations that protect against strong sunlight.

These can include roller shutters, external blinds, or other suitable external shading systems.

The technical requirements must be met. Your specialist company can provide information on this.

Renewal or installation of a ventilation system

Enter the costs for the installation or renewal of a ventilation system.

Eligible systems may include:

  • central exhaust systems with demand-controlled regulation,
  • central or decentralised ventilation systems with heat recovery,
  • room-by-room ventilation units with heat exchangers,
  • compact units for energy-efficient buildings.

The ventilation system must meet the technical minimum requirements. Your specialist company can provide you with information on this.

Renewal of the heating system

Enter the costs for renewing your heating system.

The renewal of the following heating systems is tax-supported:

  • Solar collector systems
  • Biomass systems
  • Heat pumps
  • Fuel cells
  • Mini combined heat and power systems (mini CHP)
  • Connection to a heating network

As a rule, no tax reduction is possible for new gas heating systems. Special rules apply only to certain "Renewable Ready" systems whose installation began before 01.01.2023.

Digital systems for energy optimisation

Enter the costs for digital systems to control and optimise energy consumption.

This includes, for example, measurement, control and regulation technology, smart meter systems or energy management systems.

Optimisation of existing heating systems

Enter the costs for optimising your existing heating system.

The heating system must be more than two years old at the start of the work.

The following measures are eligible, among others:

  • the survey and, if necessary, analysis of the current condition,
  • the implementation of hydraulic balancing, and
  • the implementation of all necessary measures to improve energy efficiency throughout the heating system
Issue of a statement

Enter the costs for issuing the certificate.

The certificate can be issued by the executing specialist company or by an authorised specialist.

Example: You pay 120 Euro for the certificate from your heating company. Enter 120 Euro.

Has a gas condensing boiler been installed?

Select "yes" if a gas condensing boiler was installed.

This section is only relevant if the installation of the system began before 01.01.2023 and the system was intended as "Renewable Ready" for the later integration of renewable energies.

Expenses

Enter the costs for installing the gas condensing boiler, including any directly related work.

Example: You paid 18.000 Euro for the heating system, installation, and necessary connection work. Enter 18.000 Euro.

Only costs that meet the requirements for the tax reduction will be considered.

Is there evidence of hybridisation?

Select "yes" if the gas heating system has already been supplemented with renewable energy sources and you have the required proof.

The extension must have taken place within two years of the gas heating system being put into operation.

Example: Your gas heating system was installed in May 2022 and supplemented with a solar thermal system in March 2024. The specialist company has certified this. Select "yes".

Is the proof of hybridisation submitted?

Select "yes" if you will submit the proof of hybridisation with your tax return or provide it to the tax office upon request.

Without the proof, the tax reduction for this measure cannot be considered.

Was the planning / supervision carried out by an energy consultant?

Select "yes" if a qualified energy consultant planned or supervised the measure.

Example: The energy consultant checks the planned roof insulation and monitors its execution. Select "Yes".

Costs for the energy consultant

Enter the costs for planning or construction supervision by the energy consultant actually paid.

This may also include thermographic images or airtightness tests.

Have these costs also been claimed as exceptional expenses?

Select "yes" if you also wish to claim part of these costs as extraordinary expenses.

Important: The same costs cannot be considered twice. The portion claimed as extraordinary expenses will not be additionally considered under § 35c EStG.

Thereof exceptional costs for energy-related measures

Enter the portion of the costs for energy-efficiency measures that can be considered as extraordinary expenses.

Only enter the relevant share, not the total costs of the measure.

Example: Of 20.000 Euro for an energy-efficiency renovation, 4.000 Euro are for the repair of flood damage. Enter 4.000 Euro.

Thereof exceptional costs for the energy consultant

Enter the portion of the costs for the energy consultant that can be considered as an extraordinary burden.

Only enter an amount if the consultation is directly related to an extraordinary event, such as the repair of flood damage.

Example: Of 2.000 Euro in consultancy costs, 500 Euro are for planning measures after storm damage. Enter 500 Euro.

If extraordinary burdens are not taken into account for tax purposes due to the reasonable burden, a tax reduction under § 35c EStG may still be possible for this part.