Facing the decision of a complete renovation and fearing skyrocketing costs? Many online calculators provide only a rough estimate, often deviating by 30%. This guide shows you how to accurately analyse the costs of a complete renovation, avoid pitfalls, and increase the value of your property by over 20%.
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The topic briefly and concisely
The costs for a complete renovation typically range between 800 and 2,000 euros per square metre, depending on the condition of the old building.
Always plan for a financial buffer of at least 15-20% for unforeseen expenses such as asbestos or moisture damage.
State incentives from KfW and BAFA can reduce renovation costs by up to €67,500 through grants and low-interest loans.
Wondering if the estimate from an online calculator for the costs of your complete renovation is really accurate? Renovating an old building is one of the largest investments for property owners, where costs can quickly rise from €800 to over €2,000 per square metre. Inaccurate planning often leads to additional financing and jeopardises the profitability of your project. We provide you with a data-driven method to maintain control from the initial cost estimate to the final approval, uncover hidden costs, and secure government grants of up to €67,500. This way, you can transform your property into a value-stable and future-proof asset.
Cost per square metre: The basis for your calculation
The first question in any complete renovation is: What will it cost? An online calculator for renovation costs provides an initial indication, but the actual figures heavily depend on the condition and type of property. For an old building, expect costs between 800 and 2,000 euros per square metre. In cases of poor condition or high-end specifications, costs can even rise to up to 2,500 euros per square metre. For a 150 m² property, this means an investment range of 120,000 to 300,000 euros. A detailed analysis of renovation costs is therefore the first step. This basic calculation is crucial before we examine the specific cost drivers in more detail.
The 7 Biggest Cost Drivers of a Complete Renovation
After the rough estimate per square metre, the main cost drivers that can account for up to 70% of the total budget must be identified. A precise understanding of these items is crucial for realistic budget planning.
Here are the seven key areas, the renovation of which significantly influences costs:
Roof Renovation: A new cover including insulation costs between 150 and 300 euros per square metre of roof area.
Heating System: Replacing an old system with a modern heat pump can cost between 25,000 and 40,000 euros.
Windows and External Doors: You should expect to pay 750 to 1,500 euros per window, depending on the material and glazing.
Electrical Installation: The complete renewal of the electrics costs approximately 100 to 190 euros per square metre of living area.
Water and Sewage Pipes: Replacing all pipes can, including wall and floor work, cost 8,000 to 15,000 euros.
Facade Insulation: An external wall insulation system (EWIS) costs between 100 and 200 euros per square metre of facade area.
Bathroom Renovation: A completely new bathroom requires a budget of at least 15,000 to 30,000 euros.
The costs of an energy-efficient refurbishment are considerable, but they also offer the greatest potential for increasing value and savings. However, aside from these manageable expenses, unforeseen items often lurk in the background.
Hidden Risks: Allow for a 20% Buffer
What no cost estimator for a complete renovation can capture are the unforeseen defects that only become visible after the work has started. Especially in older buildings constructed before 1990, problems like dampness in the basement, asbestos contamination, or deteriorating wooden beams often occur. These "surprises" can quickly exceed the planned costs by 20-30%. Therefore, be sure to plan a financial buffer of at least 15%, preferably 20%, of the total costs. For a budget of 150,000 euros, this equates to a reserve of 30,000 euros. A professional assessment of renovation needs in advance can halve this risk. With a secured budget, you can further optimise the financing through government assistance.
Reduce costs: Take advantage of government subsidies up to 67,500 euros
The high investment costs of a core refurbishment can be significantly reduced through targeted government subsidies. The Kreditanstalt für Wiederaufbau (KfW) and the Bundesamt für Wirtschaft und Ausfuhrkontrolle (BAFA) are your key contacts here. For comprehensive refurbishment to an energy-efficient house, KfW offers a loan of up to 150,000 Euros per residential unit in Programme 261. In addition, you can receive a repayment grant of up to 45%, corresponding to a reduction in the loan amount by up to 67,500 Euros. For individual measures such as window replacement or insulation of the building envelope, BAFA grants subsidies of up to 20%. It is important to submit the applications before starting the measures. A professional funding check ensures that you do not miss out on any funds. But how reliable are the tools that provide an initial cost estimate?
Online calculators in practical test: opportunities and limitations
A cost calculator for a complete renovation is a useful tool for an initial rough cost estimate. Such calculators use statistical averages for various trades and provide you with an initial figure within minutes. However, their accuracy is limited. Most online tools cannot account for the unique condition of your property, regional price variations in tradespeople, or the quality of materials. As a result, the discrepancy between the calculated costs and reality can be 30% or more. Use these calculators as a starting point, but never as the sole basis or justification for your financial decision. For a precise analysis, a detailed renovation potential report based on the specific data of your property is essential. Ultimately, investing is not only about the costs, but about the value creation achieved through it.
Achieve Value Increase: How Renovation Increases Property Value by 30%
A complete renovation isn't just an expense, but an investment in the future value of your property. A property that has been renovated to a high standard can experience a value increase of 20 to 30%. Measures to improve energy efficiency are especially worthwhile. A house with an energy certificate of class A or B can achieve a market sale price up to 25% higher than a comparable property of class G. The focus should therefore not just be on aesthetics, but on technical and energy modernisation. A well-planned renovation before sale enhances appeal to buyers willing to pay more for lower utility bills and high living comfort. The right strategy transforms high renovation costs into a profitable asset.
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A cost calculator for a comprehensive renovation provides a valuable initial orientation but does not replace detailed planning. The key to a successful renovation lies in a structured approach: Start with a realistic cost estimate of 800 to 2,000 euros per square meter, identify the main cost drivers, and plan a 20% buffer for unforeseen expenses. Use government grants to relieve your budget by up to 67,500 euros. Do not view the renovation as a cost factor, but as a strategic investment that can increase the value of your property by up to 30%. A data-driven analysis, like the one Auctoa offers with ImmoGPT, protects you from costly wrong decisions. A well-planned renovation is the surest way to a value-stable and future-proof property.
Additional useful links
The Federal Statistical Office offers comprehensive information on construction prices and the property price index.
Detailed data on the construction price index is available on the website of the Federal Statistical Office.
Frequently asked questions about the construction cost index are answered by the Federal Statistical Office in their FAQs.
The Federal Statistical Office provides specific price indices for residential buildings.
The KfW informs private individuals about the possibilities and benefits of energy-efficient renovation of existing properties.
An overview of funding products for energy-efficient refurbishment of existing properties is provided by the KfW.
Current tables and data on construction prices and the property price index are available on the website of the Federal Statistical Office.
FAQ
Can I deduct the costs of a complete renovation from tax?
As a landlord, you can offset the costs of a complete refurbishment against tax as maintenance expenditure over several years. For owner-occupiers, tradesmen services of up to €1,200 per year (20% of a maximum of €6,000 in labour costs) are tax-deductible. However, the use of KfW or BAFA subsidies usually excludes a tax deduction for the same measure.
How long does a full renovation take?
The duration of a core renovation for an average single-family home typically ranges from six to twelve months. The exact time depends on the scope of the work, the coordination of trades, and unforeseen complications.
Is a complete renovation worthwhile for an inherited property?
Whether a complete renovation is worthwhile depends on the market value, location, and condition of the inherited property. A renovation can significantly increase the resale value or enable profitable letting. A data-driven analysis, as offered by Auctoa, helps you make the most economical decision between renovating, selling, or letting.
What is the difference between restoration, renovation, and modernisation?
A renovation is purely aesthetic (e.g., painting). A modernisation enhances the living standard (e.g., a new bathroom). A refurbishment restores the original condition and rectifies defects (e.g., roof repair). Core refurbishment is the most comprehensive form and renews the building down to the supporting structure.
What role does the energy certificate play in refurbishment?
The energy performance certificate is central. It documents the energy condition before renovation and the standard achieved thereafter. A significant improvement in the energy efficiency class (e.g., from G to B) is a key driver for increasing value and is often a prerequisite for receiving funding.
How can Auctoa assist me in my renovation decision?
Auctoa provides an objective, data-driven basis for decision-making with ImmoGPT and detailed renovation potential reports. We analyze the condition of your property, estimate renovation costs more precisely than any standard online calculator, and calculate the expected increase in value. This allows you to make informed decisions about which measures are truly worthwhile for you.
