Renovation obligations when buying a house: What the GEG requires

Article L-0105 · 09.10.2026 · 7 min. reading time · Joé Christian Ewrard

What does the renovation obligation mean when buying a house?

There is no general obligation to carry out a complete energy renovation of a purchased house. A change of ownership does not automatically require either façade insulation or the replacement of all windows. A poor energy efficiency rating alone likewise does not require a complete renovation.

Since the end of July 2026, the law previously known as the Building Energy Act has officially been called the Building Modernisation Act. Because many people still search for “GEG” and older documents use this term, you will currently encounter both names. The current version of the law is authoritative. The retrofitting obligations relevant to a change of ownership are now set out in particular in Sections 35 and 69 of the Building Modernisation Act. [Current version of the law](https://www.gesetze-im-internet.de/geg/BJNR172810020.html)

The purchase does not create a new obligation in every case. Rather, a change of ownership often ends an exemption that benefited the previous owner. Buyers must therefore know more than just the condition of the house. They must also establish whether and when a transfer of ownership has already taken place since the statutory cut-off date.

Which houses are subject to the two-year deadline?

The rule for detached and semi-detached houses in which the owner at the time occupied one of the residential units in early February 2002 is particularly important. This owner may have been exempt from certain retrofitting obligations. The exemption ends upon the first transfer of ownership after this cut-off date. The new owner then generally has two years to carry out the relevant measures.

The word “first” is crucial. If the house has already been sold or transferred once since the cut-off date, the deadline began at that time. A further sale does not automatically restart it. If it has already expired and the measure was not carried out, the buyer does not receive a new two-year period. Instead, the buyer acquires a building for which an obligation may already be due.

In a standard property purchase, ownership usually transfers only when the new owner is entered in the land register, not when the notarised purchase agreement is signed or the keys are handed over. The classification may differ for gifts, inheritances, co-ownership interests and special transfer arrangements. Such cases should be clarified in advance with the notary or a lawyer specialising in property law.

What specific retrofitting obligations may arise?

The first important obligation concerns the top-floor ceiling beneath an unheated roof space. If this ceiling does not meet the statutory minimum thermal insulation standard, it must be insulated. The obligation is deemed fulfilled if the roof above is already adequately insulated instead or meets the required minimum thermal insulation standard. The ceiling therefore does not also have to be insulated if the roof can be shown to meet the requirement. [Section 35 GModG](https://www.gesetze-im-internet.de/geg/__35.html)

In practice, this can rarely be determined from the visible construction alone during a viewing. A clad sloping roof does not in itself prove that it has been professionally insulated. Conversely, an unremarkable top-floor ceiling may already have an adequate construction. Invoices, building specifications, photos from the construction phase and an inspection by a qualified energy consultant or expert are helpful.

The second obligation concerns uninsulated, accessible heating and hot water pipes and their associated fittings in unheated rooms. Typical locations include basements, boiler rooms, eaves spaces or other cold areas of the building. Accessibility, location and the existing state of the insulation are decisive. Pipes within heated rooms are not covered by this rule solely because of a change of ownership. [Section 69 GModG](https://www.gesetze-im-internet.de/geg/__69.html)

At first glance, both measures appear manageable. Nevertheless, their implementation should be planned from a technical perspective. Moisture, airtightness, connections and the future use of the roof space all play a role in the case of the top-floor ceiling. Unsuitable work may cause damage later.

When does the deadline begin and how is it verified?

The statutory deadline is two years from the first transfer of ownership after the relevant cutoff date. Buyers should therefore not look solely at the date of their own purchase agreement. The ownership history of the house is required.

Before the notary appointment, it should be established how long the seller has owned the property and how they acquired it. If it has already been transferred since the beginning of February 2002, it should also be checked whether the work required at that time was carried out. Suitable evidence includes contractor declarations, tradespeople's invoices, technical documents and clear photos.

A lack of supporting documents does not in itself prove a violation. However, it is a risk that should be professionally investigated and taken into account when planning the financing. A verbal statement such as “The roof was done at some point” answers neither the question of its construction nor whether it meets the statutory standard.

The purchase agreement can document which information and documents the seller has provided. Anyone requiring a binding provision regarding responsibility, condition or possible breaches of obligations should have it drafted with the notary or a lawyer. An estate agent can compile documents and highlight questions, but cannot provide legal advice.

Does an old heating system have to be replaced after the purchase?

No, not solely because of the change of ownership. The previous general requirement to replace certain old boilers was abolished following the legislative amendment in summer 2026. The provisions that previously applied have been removed from the current version of the law. Older guides frequently still present this differently.

However, this does not mean that every existing heating system may continue to operate unchanged indefinitely. Other technical, emissions-control or safety-related requirements may still be relevant. Statutory requirements also apply as soon as a heating system is actually replaced. An operational existing heating system and the planned installation of a new heating system are legally distinct situations.

Buyers should therefore not ask only about age and fuel. The condition of maintenance, availability of spare parts, consumption, chimney sweep records and the building's suitability for future heating solutions are important. Whether it makes economic sense to continue operating a heating system is a technical and financial decision. It is not the same as an obligation to replace the system triggered directly by the purchase.

When do voluntary works trigger further requirements?

Anyone who simply moves in after purchasing the property and does not alter any affected building components is not required to fully replace the windows, façade or roof solely because of the purchase. However, if exterior building components are replaced or altered on a larger scale, the work carried out must meet the applicable energy-efficiency requirements.

This applies, for example, to a planned roof replacement, the comprehensive replacement of windows or work on the façade. The obligation then arises from the specific construction work, not from the purchase itself. Minor repairs must be assessed differently from extensive renovation.

It is therefore important to proceed in the right order. First, it should be determined which measures are required by law. This should be followed by comprehensive technical planning. Only then should individual trades be commissioned. Anyone who tackles the windows first, then the heating system and subsequently the roof or façade without an overall plan risks unnecessary duplication of work or poorly coordinated building services.

What should buyers check before the notary appointment?

The energy performance certificate is an important starting point. As a general rule, it must be made available to prospective buyers no later than the viewing and handed over after the contract has been concluded. When a detached or semi-detached house is sold, the law also provides for an informational consultation on the energy performance certificate if this is offered free of charge as a standalone service. [Section 80 GModG](https://www.gesetze-im-internet.de/geg/__80.html)

However, the energy performance certificate is neither a renovation roadmap nor a detailed assessment of the property’s condition. It shows the building’s energy-efficiency classification but does not reliably indicate whether every pipe is insulated, how a concealed roof structure was constructed or when a previous transfer of ownership took place.

A building-specific assessment is therefore advisable. This should include the energy performance certificate, any available records of modernisation work, the land register or known ownership history, chimney sweep records and a professional inspection of the critical areas. The planned measures should then be included in the financing on the basis of realistic quotations.

For completed energy-efficiency work, the specialist contractor should issue a contractor’s declaration. It serves as evidence that the building components or systems installed comply with the statutory requirements. This declaration should be kept permanently with the property records and, in the event of a subsequent sale, passed on together with invoices and technical documents. [Section 96 GModG](https://www.gesetze-im-internet.de/geg/__96.html)

What is particularly important for houses in the Eifel?

In the Eifelkreis Bitburg-Prüm, Trier-Saarburg and the Vulkaneifel, buyers often encounter buildings that have been extended over time or modernised in stages. A residential property may have an older core, a later extension and roof sections constructed in different ways. A blanket statement that “The roof is insulated” is not sufficient for such buildings. Each relevant area should be considered separately.

Unheated basements, former utility rooms and hard-to-inspect eaves spaces also deserve attention. Heating and hot-water pipes often run through these areas in particular. For the legal assessment, it is not the overall impression of the property that matters, but the specific route of the pipes, their accessibility and the condition of their insulation.

For properties in the Trier area or near the Luxembourg border, financing, place of work and the time available for renovations are also often closely linked. This makes it all the more important not to discover necessary work only after the keys have been handed over. A preliminary technical assessment turns a general concern into a manageable list of tasks.

Are there any exceptions or exemptions?

The law provides for exceptions and the possibility of an exemption in cases of undue hardship. For certain owner-occupied single-family and two-family homes, the cost-effectiveness of insulating the top-floor ceiling may also be relevant. However, an exception should never be assumed solely on the basis of a rough cost estimate.

An exemption from the authorities generally requires an application and verifiable supporting documentation. Particular structural, financial or personal circumstances may be taken into account. The competent authority decides whether the requirements are met on a case-by-case basis. [Section 102 GModG](https://www.gesetze-im-internet.de/geg/__102.html)

For listed buildings, particularly valuable historic building fabric, unusual structures or transfers within the family, professional advice should be sought at an early stage. Qualified energy consultants and experts are responsible for technical matters. Legal questions should be referred to a notary or lawyer, and tax implications to a tax adviser.

Before the notary appointment, first have the ownership history checked, then the roof or top-floor ceiling, and finally any accessible pipes. PRIOCASA can organise the available documents and highlight unresolved matters during the sales process; the technical assessment is carried out by a qualified professional, while legal and tax matters are clarified by a notary, lawyer or tax adviser.

Frequently Asked Questions

Do I have to renovate within two years after every house purchase?

No. There is no general obligation to carry out a complete renovation. The two-year period applies to certain upgrades and a specific exception for previously owner-occupied single-family and two-family homes.

Does the period begin with the notary appointment or the handover of the keys?

For a standard property purchase, the transfer of ownership through entry in the land register is generally decisive. In the case of inheritance, gifts or special ownership arrangements, legal advice should be sought to determine when the period begins.

Do I receive another two years if the property is resold?

Not automatically. The law refers to the first transfer of ownership after the cut-off date. If this took place earlier, the period may already have expired.

Does an old oil or gas heating system have to be removed because of the house purchase?

Under the current version of the law, a change of ownership alone no longer triggers a general obligation to replace the boiler. However, when a heating system is actually replaced, the requirements applicable at that time must be met.

Is the energy performance certificate sufficient for checking the renovation obligation?

No. It provides an overview of the property's energy performance, but does not replace an inspection of the building components or a review of the ownership history. The roof or top-floor ceiling, pipes and existing documentation should be checked separately.

Who is liable if the seller has not completed an upgrade that was due?

That depends on the statutory responsibility, the information provided by the seller and the provisions of the purchase agreement. Have such a case reviewed by a notary or lawyer before the purchase.

Topics: renovation obligation when buying a house, Buildings Energy Act, Building Modernisation Act, change of ownership, energy-efficient renovation, Eifel, Trier, Bitburg-Prüm

Responsible for this article: Joé Christian Ewrard — Owner & IHK-certified real estate agent, PRIOCASA Immobilien & Finanzservice. Last updated: 09.10.2026. The draft was created with the support of artificial intelligence and reviewed and approved before publication (AI Transparency). This post does not replace legal or tax advice; for individual questions, please contact a notary, lawyer, or tax advisor.

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