Do you own or have you inherited a flat from the 1970s and are wondering what costs you might face when modernising it? Many owners underestimate the effort, which can quickly exceed €1,000 per square metre. This guide will show you how to realistically plan your budget and avoid expensive surprises.
Chat with ImmoGPT for free now.
With access to Google, BORIS, and Deep Research.
The topic briefly and concisely
For a comprehensive renovation of a 1970s apartment, expect costs of 900 to 1,400 euros per square metre.
The energy renovation (windows, insulation, heating) is the biggest lever for increasing value and is subsidised by the government by up to 70%.
Hidden defects such as asbestos or moisture can unexpectedly increase costs by more than 20%; a professional analysis is therefore essential.
An inherited flat from the 70s – blessing or financial curse? The building structure is often solid, yet outdated technology and lack of insulation pose significant cost risks. Modernisation costs for a 70s flat can quickly escalate without precise planning. Expect to spend between 900 and 1,400 euros per square metre for a comprehensive renovation. This article provides you with a data-driven breakdown of the costs involved, from electrics to energy refurbishment. This way, you can transform an ageing property into a value-stable home and make well-informed decisions that pay off in the long term.
The basis: Accurate assessment of refurbishment needs
Before creating budgets, a professional inventory is essential. Buildings from the 1970s have specific weaknesses that often only become apparent at second glance. The first thermal insulation regulation did not come into force until 1977, which is why insulation is almost always inadequate. Typical deficiencies include outdated electrics, corrosion-prone water pipes made of zinc or steel, and panoramic windows with poor insulation values. A pollutant check is also advisable, as materials like asbestos or formaldehyde were used in up to 60% of buildings from this era. A detailed analysis protects you from unforeseen expenses that can exceed your budget by 20-30%. This initial phase lays the foundation for cost-effective renovation.
Core renovation: Costs for electrics, plumbing, and heating
The renovation of building services is the largest cost factor when modernising a 70s-era apartment. For a complete electrical refurbishment, you should budget between 80 and 150 euros per square metre of living space. A new electrical installation is essential for safety reasons after more than 50 years. The bathroom renovation can incur costs between 3,000 and 5,000 euros per square metre of bathroom area, with just the dismantling and disposal of old tiles potentially costing up to 350 euros per square metre. The heating system usually needs to be completely renewed, which, depending on the system (e.g. heat pump), is estimated at 15,000 to 30,000 euros. A precise renovation cost calculator helps to understand these key expenses. These investments are crucial for future safety and living comfort.
Energy-efficient renovation for value enhancement
Energy-efficient refurbishment is not a cost factor, but an investment that increases property value by up to 30% and permanently reduces ancillary costs. The costs for energy-efficient measures range between 200 and 500 euros per square metre. A complete window replacement costs around 1,500 euros per window. Insulating the facade can cost between 150 and 250 euros per square metre. The state generously supports these measures: Through the Federal Funding for Efficient Buildings (BEG), grants of up to 70% for a new heating system are possible. A funding check is therefore a must. The following list shows typical measures:
Replacement of windows with triple glazing (approx. 20% energy savings).
Insulation of the top floor ceiling (costs approx. 25-60 €/sqm).
Installation of a modern heating system with renewable energies (up to 50% lower heating costs).
Facade insulation to reduce thermal bridges (savings of 15-25% of heating energy).
These measures are key to making a 1970s flat fit for the future.
Interior construction: Costs for floors, walls, and doors
Following the technical trades, the visible part of the modernisation takes place. The cost of interior construction is heavily dependent on material choice. For new flooring, such as parquet or high-quality tiles, you should budget between 50 and 150 euros per square meter. Plastering and painting the walls costs approximately 20 to 35 euros per square meter, including materials. Replacing old interior doors improves not only aesthetics but also sound insulation, costing between 300 and 700 euros per door. With a budget of 10,000 euros for a 70-square-meter apartment, a significant visual enhancement can be achieved here. A well-thought-out planning of renovation costs is crucial to success. These final steps significantly influence the living quality and first impression during a potential sale.
Identify cost traps and potential savings
The biggest hidden costs are lurking. Asbestos in tile adhesives or insulation can drive renovation costs up by over 1,000 euros per square metre. Moisture damage in the basement, due to the end of the technical lifespan of the sealant, can quickly cause costs of over 10,000 euros. Savings potential lies mainly in personal contribution, which can reduce costs by up to 40% in electrical renovation (e.g. cutting slots). Other cost-saving possibilities are:
Obtaining at least 3 comparative quotes for each trade.
Careful examination of funding opportunities, which can cover up to 20% of the total costs.
Using standard sizes for windows and doors, which reduces costs by 15-25%.
Engaging an energy consultant, whose fee is 50% subsidised and who prevents inefficient measures.
A data-driven analysis, as offered by the Auctoa Sanierungspotenzial-Bericht, objectively reveals these risks and opportunities. This ensures that your budget is not consumed by unforeseen expenses.
Conclusion: Planning is the key to success
The modernisation costs for a 1970s flat are considerable, but with precise planning and professional support, they can be manageable. Expect an overall budget of at least 60,000 euros for a 70-square-metre flat to bring it up to a contemporary standard. An energy-efficient renovation is not only mandatory but also enhances the long-term value of your property. Use AI-assisted assessments to determine the exact renovation needs and potential for value increase. This way, you make well-informed decisions based on facts, rather than intuition. A well-planned renovation is the best investment in the future of your property.
modernisierungskosten-fur-eine-70er-jahre-wohnung
Additional useful links
BUND offers a study on climate protection in rental apartments from the year 2024.
Gesetze im Internet contains Section 559 of the BGB, which regulates rent increases following modernization measures.
BRAK (Federal Bar Association) provides a news article about how landlords do not need to explain modernization costs in detail.
KfW offers an overview of its funding products for existing properties for private individuals.
KfW provides information about the KfW Loan 261/262 to promote energy-efficient residential buildings.
KfW provides current press releases.
Statistikportal.de offers statistics on residential buildings by year of construction.
Destatis (Federal Statistical Office) contains a glossary entry on the subject of year of construction.
Destatis (Federal Statistical Office) publishes press releases.
FAQ
What is the pure modernisation cost per square metre?
The costs vary greatly depending on the extent. For a comprehensive refurbishment of a 1970s property, the costs range between 900 and 1,400 euros per square meter. A purely energy-related renovation costs about 200 to 500 euros per square meter.
What government grants can I use for the renovation?
You can apply for grants and low-interest loans from KfW (e.g. Programme 261) and BAFA. Funding is available for individual measures such as heater replacement (up to 70% subsidy) or complete renovations to an efficiency house. Alternatively, you can claim a tax deduction of 20% of the costs.
How long does it take to renovate a 1970s apartment?
A complete renovation of a flat usually takes between 3 and 6 months, depending on the scope and coordination of the trades. Smaller modernisations can be completed in a few weeks.
What are the most common unforeseen costs?
The most common unforeseen costs arise from the discovery of hazardous substances (asbestos, PCBs), which require expensive specialist disposal, as well as from moisture damage to the building fabric, which only becomes visible after opening walls or floors.
Can I really save money by doing it myself?
Yes, by doing tasks like demolition, chiselling grooves, or painting yourself, you can significantly reduce the costs of craftsmen, sometimes by up to 40% for certain trades. However, tasks related to electrics or water pipes should always be left to a professional.
How does Auctoa help me plan my modernization?
Auctoa provides a data-driven property valuation and a refurbishment potential report. Our analysis objectively identifies the condition of your property, the refurbishment needs, and the potential costs. With our ImmoGPT, you can also quickly address initial questions, thus creating a well-informed decision-making basis for your project.
