Do you own or inherit an old building and wonder how to tackle the renovation obligation? Sustainable renovation of an old building is not only a legal requirement, but also your greatest opportunity. You can reduce energy consumption by up to 80% and significantly increase the property's value.
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The topic briefly and concisely
Legal Pressure: New owners must renovate within two years according to GEG, otherwise they face fines of up to €50,000.
High yield: An energy-efficient refurbishment can reduce energy consumption by up to 80% and increase property value by over 15%.
Maximum funding: By combining KfW and BAFA programmes, you can receive grants of up to 67,500 euros for your renovation.
Rising energy costs and the updated Building Energy Act (GEG) present challenges for homeowners. But what if these obligations were a strategic opportunity? A well-thought-out, sustainable renovation of an old building can transform the existing structure into a future-proof, value-stable home. It's about not only meeting the minimum legal standards but using them as a lever for increased living quality and financial returns. This article shows you how to strategically plan your renovation, which measures have the greatest impact, and how to secure up to €67,500 in government funding. This way, an obligation becomes one of the best investments in your property.
Why the time for a renovation is now pressing
The Building Energy Act (GEG) sets clear deadlines for new owners of existing properties. After purchase, you have exactly two years to implement mandatory energy measures. Failure to comply can result in fines of up to 50,000 euros.
The obligation to renovate primarily affects buildings constructed before 1978 that have not yet undergone comprehensive modernisation. In particular, the replacement of boilers over 30 years old is one of the central demands of the GEG. Exceptions are low-temperature and condensing boilers, which are already more efficient.
An additional requirement is the insulation of the top floor ceiling or the roof. Here, the legislator stipulates a thermal transmittance coefficient (U-value) of no more than 0.24 W/(m²K). This measure alone can already reduce heating energy loss by 10-20%. With an energy-efficient modernisation, you not only meet the legal requirements but also lay the foundation for the next step: increasing value.
Strategically weigh up costs and returns
A comprehensive renovation of an old building costs on average between 800 and 1,200 Euros per square metre. For a living area of 140 m², this corresponds to an investment of around 112,000 to 168,000 Euros. These figures may initially seem high, but the return is compelling.
Through a complete energy-efficient renovation, the energy requirements of an old building can be reduced by up to 80%. With current energy prices, this means an annual saving of several thousand Euros. The investment often pays off within 10 to 15 years just through the savings in operating costs.
In addition, a renovation significantly increases the market value of your property. Energy-efficient buildings achieve on average a 15-20% higher price when sold. A data-supported evaluation before and after the measure, as offered by Auctoa, precisely quantifies this added value. Thus, a pure cost consideration becomes a clear investment calculation, paving the way for financing.
The most effective remediation measures in focus
Not every measure provides the same benefit. Prioritising is crucial for the success of your sustainable old building renovation. The greatest effects are achieved with a combination of insulation, window replacement, and modern heating technology.
Insulating the building envelope is the most important step. Professional facade insulation can reduce heating costs by up to 25%. Replacing old, single-glazed windows with modern triple glazing reduces heat loss in these areas by over 50%. These measures are the basis for the next step.
Here are the key levers for a successful renovation:
Roof insulation: Up to 30% of heating energy is lost through an uninsulated roof. An above-rafter or between-rafter insulation is the most effective solution here.
Window replacement: Modern windows with a U-value of less than 1.3 W/(m²K) are now standard and a legal requirement when more than 10% of the window area is being renewed.
Heating modernisation: Switching to a heat pump, often in combination with a photovoltaic system, meets the 65% renewable energy requirement of the GEG.
Basement ceiling insulation: An often underestimated but cost-effective measure that noticeably improves living comfort on the ground floor by 5-10%.
The right combination of these measures, tailored to your building, is crucial. A detailed analysis, as provided by our ImmoGPT chat, helps you find the optimal strategy for your tips on old building renovation.
Sustainable Building Materials: More Than Just Ecology
The choice of the right materials is a key aspect of sustainable renovation of old buildings. Natural building materials such as wood, hemp, cellulose, or clay offer far more than just a good ecological balance. They demonstrably improve the indoor climate through their ability to regulate moisture.
Cellulose insulation, made from recycled newspaper, provides excellent summer heat protection, enabling interior temperatures to be up to 7 degrees cooler. Wood fibre insulation boards have similar properties and also store CO2. Clay plaster on the interior walls can bind and neutralise pollutants from the air.
These materials are often particularly suitable for the fabric of old buildings. They are open to diffusion, meaning they can absorb and release moisture. This significantly reduces the risk of mould, a common problem in improperly renovated old buildings. A focus on sustainable building materials is thus an investment in the longevity of the structure.
Intelligently use funding and reduce costs
The investment in sustainable renovation is heavily supported by the government. The Federal Funding for Efficient Buildings (BEG) offers attractive grants and loans through the KfW Bank and BAFA. Those who renovate their house to an efficiency house standard can receive a loan of up to 150,000 euros with a repayment grant of up to 45% through the KfW program 261. This means a reduction of the loan amount by up to 67,500 euros.
For individual measures such as window replacement or insulation, there are grants available from BAFA. These are usually between 15-20% of the eligible costs. It is important to submit applications before starting any construction measures. A certified energy efficiency expert is required for most applications.
This is how you secure maximum funding:
Energy consultation: An individual renovation roadmap (iSFP) is subsidised by up to 80% and increases the funding rates for individual measures by an additional 5%.
Combine loan and grant: The KfW complementary loan (358/359) can be combined with BAFA grants for individual measures.
Utilise income bonus: Households with a taxable annual income of under 90,000 euros receive an additional interest reduction on KfW loans.
Heating exchange bonus: For the replacement of an old fossil-based heating system with one based on renewable energies, bonuses of up to 70% are available.
Navigating through the funding jungle is complex. Early planning and advice on green funding is key to not throwing away money.
Conclusion: Achieve Success with a Data-Driven Strategy
A sustainable renovation of old buildings is the logical response to legal obligations and rising energy costs. It not only preserves the value of your property but actively increases it. A reduction in energy costs by 80% and an increase in value of over 15% are realistic goals.
The key lies in strategic planning based on a neutral, data-driven analysis of the current state. Do not rely on gut feeling. A professional property valuation from Auctoa delivers the facts you need for an informed decision. This is how you turn a complex challenge into a profitable investment in your future.
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Additional useful links
Umweltbundesamt offers everyday environmental tips focusing on heating, building, and renovation.
Umweltbundesamt provides comprehensive information on energy-efficient building renovation.
Destatis publishes press releases and statistics on the construction and housing industry.
KfW provides information on funding programmes for individuals for energy-efficient renovation of existing properties.
KfW lists specific funding products for the energy-efficient renovation of existing properties.
KfW explains the eligible measures to increase energy efficiency in renovation projects.
dena offers a compact building report from 2018, providing insights into the building sector and energy efficiency.
FAQ
Do I need to renovate if I have owned the house for a long time?
No, the renovation obligation under the Building Energy Act (GEG) typically only applies when there is a change of ownership (purchase, inheritance, gift). If you have been living in your single or two-family house since before 1 February 2002, you are exempt from the retrofit obligations.
Is a heat pump worthwhile in an unrenovated old building?
A heat pump can also operate efficiently in older buildings, but it benefits enormously from energy improvements. Good insulation and replacing old windows reduce the required flow temperature, which can increase the heat pump's efficiency by 20-30%. Prior energy consulting is crucial here.
What is an individual renovation timetable (iSFP)?
The iSFP is a document prepared by a certified energy consultant that analyzes the energy status of your property and presents a step-by-step plan for meaningful renovation measures. The creation of this document is government-subsidized and also increases the funding rate for many individual measures by 5%.
Can I combine funding?
Yes, a combination is often possible and makes sense. For instance, you can combine BAFA grants for individual measures with a KfW supplementary loan (358/359). However, you should clarify the exact combination rules with an energy consultant beforehand.
What happens if I miss the two-year renovation deadline?
If you do not implement the renovation measures stipulated in the GEG within two years of the property transfer, you commit an administrative offence. The responsible authority may impose a fine of up to €50,000.
How does Auctoa help me with my renovation decision?
Auctoa offers a fast, data-driven, and impartial property valuation. We analyse the current market value and potential of your property. With our ImmoGPT chat, you can also address initial questions and understand which measures have the greatest financial leverage for your specific situation.
