Estimating your renovation budget: a practical buy or rent guide

Why your renovation budget can flip the buy or rent equation

Two homes, same listing price: one fully renovated, the other “with great potential”. On paper they look similar, but the renovation budget can easily reach 10–40% of the purchase price and totally change whether it makes more sense to buy or rent.

Our buy-or-rent.net simulator uses a key parameter: montant_travaux (total renovation cost). If this is wrong, the whole comparison is biased. If it’s realistic, you can finally compare apples to apples: keep renting and invest your savings, or buy, renovate and repay a mortgage.

The main components of a renovation budget

Before we talk numbers, break your renovation budget into clear cost blocks. A serious estimate is more than a random cost per square meter.

1. Structure and heavy work

• Opening a load‑bearing wall: €2,000–€8,000 depending on span, steel beam, engineering.
• Floor reinforcement: €80–€200/m².
• Full roof replacement: €150–€250/m² of roof surface.

Example: 100 m² house with 80 m² of roof to replace at €200/m² = €16,000, before insulation.

2. Energy renovation (insulation, windows, heating)

This is strategic because it affects your energy rating, monthly bills and resale value.

• Internal wall insulation: €40–€80/m² of wall.
• Replacing single‑glazed windows: €500–€900 per window.
• Heat pump: €10,000–€18,000 installed.

Example: 70 m² flat with 6 windows to replace and 50 m² of walls to insulate:

• Windows: 6 × €700 ≈ €4,200
• Insulation: 50 × €60 ≈ €3,000

Already €7,200 in your renovation budget just for the thermal envelope.

3. Kitchen, bathroom and wet rooms

• Fitted kitchen: €3,000–€12,000 (excluding luxury), including installation.
• Complete bathroom: €5,000–€15,000 depending on range and plumbing complexity.
• WC: €1,000–€2,500.

For a two‑bed apartment with a kitchen and one bathroom to redo, realistic ranges:

• Entry level: €4,000 (kitchen) + €6,000 (bathroom) = €10,000.
• Mid‑range: €7,000 + €9,000 = €16,000.

4. Cosmetic work and finishes

• Painting walls and ceilings: €20–€35/m² of wall/ceiling surface.
• Flooring (laminate, tiles): €30–€80/m² installed.
• Electrical upgrade: €60–€120/m² for a full rewire.

Example: global refresh of a 60 m² flat:

• Paint (about 150 m² of walls/ceilings) at €25/m² = €3,750.
• Floors on 50 m² at €45/m² = €2,250.
• Electrical upgrade at €90/m² = €5,400.

Total refresh: €11,400.

Three quantified renovation scenarios per m²

To plug montant_travaux into a buy or rent simulation, cost per square meter is a useful starting point.

Scenario 1: basic refresh (€200–€400/m²)

For a sound property with no major issues:

• Painting: €80–€150/m² of living area.
• Some flooring changes: €50–€100/m² on part of the home.
• Minor fixes, light fixtures, taps: €1,000–€3,000.

For 50 m²: typical range €10,000–€18,000, i.e. €200–€360/m².

Scenario 2: full renovation (€600–€1,000/m²)

Kitchen, bathroom, floors, paint and part of the electrics are redone.

For 70 m²:

• Kitchen: €7,000
• Bathroom: €9,000
• Floors (70 m² × €60): €4,200
• Paint (180 m² × €25): €4,500
• Partial electrics (70 m² × €70): €4,900

Total: €29,600, about €420/m². With contingencies and extra finishes, you easily reach €35,000, about €500/m². In hot markets or with higher‑end finishes, €800–€1,000/m² is common.

Scenario 3: heavy renovation with energy upgrade (€1,000–€1,500/m²)

Structure, heating, insulation and windows are all involved.

For a 100 m² house:

• Roof: €16,000
• Wall insulation: 80 m² × €70 = €5,600
• Windows (10 × €800): €8,000
• Heat pump: €14,000
• Full rewiring (100 m² × €110): €11,000
• Plumbing, kitchen, bathroom, floors, paint: €40,000

Total ≈ €94,600, about €950/m². Add 10–15% for surprises and you are near €105,000, or €1,050/m².

How renovation cost affects your buy or rent decision

The montant_travaux parameter does more than raise the total price. It affects several levers that change the buy or rent outcome.

1. Loan amount and monthly payment

Assume:

• Property price: €250,000
• Renovation: €50,000
• Down payment: €40,000
• Loan rate: 3.6%
• Term: 25 years

Amount to finance = €250,000 + €50,000 + ~€20,000 fees (notary + agency, rough estimate) − €40,000 = €280,000.

At 3.6% over 25 years, the monthly payment (excluding insurance) is about €1,420. If renovation were only €20,000, total finance would be €250,000 + €20,000 + 20,000 − 40,000 = €250,000, for a payment around €1,270. An extra €30,000 of works = roughly €150/month more for 25 years.

2. Borrower insurance and prepayment penalties

With an insurance rate of 0.30% on €280,000, annual insurance cost is about €840, or €70/month. If you sell earlier than planned and repay the loan, prepayment penalties can reach 3% of remaining principal or six months of interest. The larger the loan (including renovation), the larger these amounts.

3. Effect on future property value

Spending €50,000 on works does not guarantee a €50,000 value increase. It depends on:

• Local market conditions.
• Energy rating improvement (jumping from F to C has more impact than C to B).
• Finish quality and buyer expectations.

Example: you buy a flat for €200,000 and spend €60,000 on works (so €260,000 invested before fees). If the market allows a resale at €3,800/m² for 70 m², that’s €266,000. The gross gain is only €6,000 before selling costs, property tax, inflation. In such a case, renovation mainly improves comfort and bills, not necessarily your financial return.

Comparing buy or rent with renovation included

To evaluate whether to buy or rent, you must compare two consistent scenarios where renovation cost is correctly integrated.

Scenario A: you buy and renovate

Typical parameters to enter in the simulator:

• Purchase price: €220,000
• Montant_travaux: €40,000
• Notary fees: ~7% (older property) ≈ €15,400
• Agency fees: 4% ≈ €8,800
• Loan rate: 3.6%
• Insurance rate: 0.30%
• Property tax: e.g. €1,200/year, increasing 2%/year
• Annual inflation: 2–3%

The simulator then computes:

• Monthly mortgage payments.
• Total cost of ownership over 10, 15, 20 years (interest, insurance, property tax, maintenance).
• Potential property value at the end (with your price growth assumptions).

Scenario B: you rent and invest instead

Parameters to enter:

• Rent: e.g. €1,050/month.
• Annual rent increase (linked to national rent index): 2–3%.
• Investment rate for your savings (ETFs, savings accounts, etc.): 3–6% depending on your risk profile.

The idea is to compare, after 10–20 years:

• Your net wealth if you buy (property value − remaining loan − selling costs).
• Your net wealth if you rent (investment capital + returns − rent paid).

Here again, montant_travaux is a pivot: a “cheap” place needing €1,000/m² of works can be more expensive overall than a more expensive but already renovated property.

How to refine your renovation budget (montant_travaux)

1. Start from benchmarks, then adjust

Useful ballpark ranges:

• Refresh: €200–€400/m².
• Full renovation: €600–€1,000/m².
• Heavy renovation: €1,000–€1,500/m².

Then adjust:

• Upwards if the energy rating is poor, the building is very old, or you are changing the layout.
• Downwards if only cosmetics are needed.

2. Get multiple quotes

For any serious project, obtain at least 2–3 contractor quotes. For your simulation, you can enter in the buy or rent tool a montant_travaux slightly higher (say +10%) to cover unforeseen issues.

3. Add a contingency margin

Renovation surprises are common: hidden damage, updated electrical standards, material price hikes. A prudent rule of thumb:

• +10% contingency for a simple refresh.
• +15–20% for heavy or energy renovation.

If your quotes sum to €60,000, use €70,000–€72,000 as montant_travaux in your simulation.

Common mistakes when estimating renovation cost

• Forgetting side costs: architect, structural engineer, permits, extra diagnostics, temporary accommodation during works.
• Confusing material price with installed price: a €4,000 kitchen can easily cost €6,000 including fitting and plumbing.
• Underestimating timelines: the longer the project, the more months you might pay both rent and mortgage.
• Ignoring energy impact: some works (insulation, heating) reduce monthly bills; others (pure decoration) don’t.

Case study: same flat, three renovation budgets

Imagine a 60 m² flat in need of work. Purchase price: €180,000. You hesitate between three renovation levels:

• Option 1 – Minimal refresh: €15,000 (paint + partial flooring).
• Option 2 – Full standard renovation: €35,000.
• Option 3 – High‑end with energy works: €60,000.

Assume:

• Loan rate: 3.6%.
• Insurance rate: 0.35%.
• Notary + agency fees: €18,000 (approx.).
• Down payment: €30,000.

Total loan for each option:

• Option 1: 180,000 + 15,000 + 18,000 − 30,000 = €183,000.
• Option 2: 180,000 + 35,000 + 18,000 − 30,000 = €203,000.
• Option 3: 180,000 + 60,000 + 18,000 − 30,000 = €228,000.

Monthly payments (principal + interest, rough) over 25 years:

• Option 1: ≈ €930/month.
• Option 2: ≈ €1,030/month.
• Option 3: ≈ €1,160/month.

Adding insurance at 0.35% increases all three, but the relative gap remains: about €230/month between minimal refresh and high‑end renovation. Over 10 years, that’s nearly €27,600 difference in cash outflow, which your buy or rent simulator will compare with rent and potential investment returns.

Conclusion: renovation cost is central to any buy or rent analysis

Montant_travaux is not just a line item tacked onto the price. It drives your loan size, your monthly payment at current ~3.6% mortgage rates, your insurance cost around 0.25–0.45%, your energy bills and your property’s future value. Depending on the case, a large renovation budget can be a smart long‑term investment—or tilt the scales in favour of renting and investing instead.

The answer to the question “buy or rent?” always depends on your situation, your time horizon and your appetite for renovation risk. This article is for information only and is not personalized financial advice.

To see the real impact, plug different montant_travaux values (€20,000, €40,000, €60,000…) into the simulator and observe how your projected net wealth changes in each scenario.

Simulate your situation on buy-or-rent.net and measure precisely how your renovation budget shapes your buy or rent decision.