Which renovations boost resale value the most?

Renovations and resale: an investment decision, not just comfort

When you ask which renovations boost resale value the most, you’re really asking an investment question: what ROI will I get on my renovation budget? In a buy or rent logic, the renovation budget (montant travaux) is a decisive parameter in any simulator: used poorly, it destroys value; used well, it creates a strong resale gain (capital gain).

In a tool like a buy vs rent simulator (e.g. buy-or-rent.net), the montant_travaux field lets you compare two strategies:

• Buy + renovate (with works amortised over your holding period)
• Rent and invest the same amount in financial assets (ETFs, savings, bonds)

The real question is not “should I renovate?”, but: which works, at what cost, for what resale uplift?

1. How to measure renovation ROI: a simple formula

To compare different renovation options, you can use a basic indicator:

Renovation ROI = (Resale value increase due to works − Total renovation cost) / Total renovation cost

Numerical example:

• Renovation budget: €30,000
• Estimated resale price without works: €300,000
• Estimated resale price with works: €340,000

Value created by the works = €40,000 − €0 (compared with initial state) = €40,000.

ROI = (40,000 − 30,000) / 30,000 = 33%

Now compare that to a scenario where you:

• Rent an equivalent home instead of buying
• Invest the €30,000 in an ETF portfolio at 4.5% per year (a realistic long-term return)

Over 10 years, €30,000 at 4.5% grows to roughly €46,500 (compounding). To be competitive, your works plus general market price growth need to generate at least as much value, after accounting for notary fees, property tax, maintenance, insurance and mortgage costs.

Important: this is for educational purposes only and is not personalised financial advice. Your situation, tax rules and local market can change the result significantly.

2. The renovations that usually add the most resale value: Top 5

2.1. Energy efficiency upgrades (insulation, heating, windows)

This category often has the highest impact on market value, especially in countries where poor energy ratings (e.g. F or G) are penalised by regulation or buyer preferences.

Example on a 60 m² two-bedroom flat rated F:

• Current price: €200,000
• Energy renovation budget: €25,000 (insulation, ventilation, efficient boiler or heat pump, double-glazed windows)
• Energy rating improved from F to C
• Potential resale uplift: +10% to +15% depending on market, i.e. €220,000–230,000

In a tight market, a €30,000 value increase for €25,000 invested means a gross ROI of 20%, not counting:

• Heating savings: say €800/year over 10 years = €8,000
• Lower discount at resale vs non-renovated properties

In your buy or rent simulation, the montant_travaux input should reflect:

• Total renovation cost (VAT included)
• Any subsidies or tax credits that reduce the net cost
• The assumed impact on resale price (a parameter you can test)

2.2. Kitchen and bathroom: the “deal-making” rooms

An outdated kitchen or bathroom often drags the price down because buyers anticipate heavy works. Conversely, modern, neutral, functional rooms tend to create a resale premium beyond their cost, as long as you avoid overspending.

Numerical example:

• Kitchen: €10,000 (mid-range cabinets and appliances)
• Bathroom: €8,000
• Total renovation budget: €18,000
• Price without works: €250,000
• Price after works: €270,000–280,000 depending on the market

Potential gain: €20,000–30,000 for €18,000 invested, i.e. a gross ROI between 11% and 66%. The spread depends heavily on:

• Neighbourhood quality (strong vs weak demand)
• Finish level (avoid top luxury in an average building)

2.3. Layout optimisation: creating one extra room

Turning a one-bedroom into a two-bedroom, or splitting a large living room into two spaces, can move the property into a more valuable market segment. Price per m² may stay similar, but total price increases because more buyers can use the layout.

Example:

• Size: 55 m²
• Before: large one-bedroom, €5,000/m² ⇒ €275,000
• After: functional two-bedroom (partition wall + electrics + door): €10,000 of works
• New price: €5,300/m² ⇒ €291,500

You create €16,500 of value for €10,000 of works, a gross ROI of 65%. In a buy or rent comparison, such a layout play can tilt the balance towards buying if:

• You live in the property for a few years
• You resell once the new layout is completed and the market recognises the value

2.4. Full cosmetic refresh: paint, flooring, interior doors

These are the classic value-add renovations: relatively low cost, strong impact on first impressions.

Example:

• Painting walls and ceilings: €5,000
• New flooring (laminate or quality vinyl): €4,000
• New interior doors: €2,000
• Total: €11,000
• Price before: €180,000
• Price after: €195,000–200,000

Gain: €15,000–20,000 for €11,000 spent, a gross ROI of 36–82%. The main benefit is also reducing time on market and limiting buyer negotiation.

2.5. “Invisible” energy improvements that still pay off

Some changes are not visually striking but do affect value: replacing an old oil boiler with a heat pump, insulating the attic, upgrading the hot-water system.

Example:

• Renovation budget: €12,000
• Energy savings: €700/year
• Energy class improved from E to D
• Resale impact: +5% on a €220,000 property ⇒ +€11,000

Over 10 years:

• Energy savings ≈ €7,000
• Resale uplift ≈ €11,000
• Total benefit ≈ €18,000 for €12,000 invested ⇒ overall ROI ≈ 50%

3. Renovations that often add little value (or even destroy it)

On the other hand, some projects have a low or negative ROI, especially if your main goal is resale, not personal enjoyment.

3.1. Over-the-top luxury in an average neighbourhood

Putting a €30,000 designer kitchen into a building where the going rate is €3,000/m² rarely makes financial sense. Buyers won’t pay the full premium.

Example:

• Luxury kitchen budget: €30,000
• Resale value increase: €10,000–15,000 only
• Gross ROI: −50% to −66%

3.2. Highly personalised works (indoor spa, extreme home cinema, etc.)

Anything very specific to your tastes has little value for the average buyer. In some cases, they see it as a future demolition cost.

Typical examples:

• Indoor jacuzzi, private sauna
• Completely blacked-out cinema room
• Very eccentric materials (aggressive patterns, very dark tiles)

These should be considered lifestyle spending, not investments aimed at resale ROI.

3.3. Heavy extensions in low-price areas

Adding a floor or a large extension can be attractive, but where market prices are low, the build cost per m² often exceeds the local value per m².

Example:

• Market price: €2,000/m²
• Extension cost: €2,800/m²
• 20 m² extension: €56,000 of works
• Value added: 20 m² × €2,000 = €40,000

You mechanically lose €16,000, even before considering higher property tax and maintenance.

4. Integrating renovation budget into a “buy or rent” strategy

The deeper question is not just: “which renovations add the most value?”, but:

Do the renovations I’m planning beat:

• A financial investment at X% per year (your assumed investment rate)
• A strategy where I stay a tenant and invest my savings instead of renovating

In a buy or rent simulator such as buy-or-rent.net, the montant_travaux field lets you:

• Add a renovation budget to the purchase (e.g. €30,000 in year 1)
• Compare the final net worth at 15 or 20 years with a scenario where you rent and invest that €30,000 at 4–5% per year

Simplified 15-year example:

• Scenario 1 – Buy + €30,000 of works
  • Purchase price: €250,000
  • Notary fees (7%): €17,500
  • Renovation budget: €30,000
  • Total outlay: €297,500
  • Resale after 15 years: €330,000 without works, €360,000 with works
  • Value added by works: €30,000
• Scenario 2 – Rent + invest €30,000 at 4.5%
  • Capital after 15 years ≈ €54,000

Looking only at the incremental effect of the works:

• Works: +€30,000 in resale value
• Financial investment: +€24,000 in interest (€54,000 − €30,000)

On paper, the renovations slightly outperform the investment. But you still need to subtract:

• Ongoing maintenance
• Extra property tax linked to a higher assessed value
• Mortgage costs (loan rate around 3.6% + borrower insurance 0.25–0.45%)

This is why simulating the numbers is more reliable than intuition.

5. How to prioritise value-adding renovations

5.1. Step 1: safety and compliance

Before thinking about resale premiums, you must:

• Bring the electrical system up to code if needed
• Fix damp, leaks, roof issues
• Address structural problems (cracks, sagging floors)

These works don’t always create visible extra value, but without them, resale is hard and buyers will negotiate aggressively.

5.2. Step 2: improve energy rating and running costs

Next, focus on what improves:

• The energy rating (e.g. G → F, F → D, etc.)
• Heating and hot water running costs

A better rating reassures buyers and lenders and reduces the risk of regulatory penalties. It’s a central piece of the buy or rent puzzle over the medium term.

5.3. Step 3: layout and key rooms

Once the technical and energy issues are fixed:

• Optimise the layout (extra bedroom, open-plan kitchen where the market values it)
• Upgrade kitchen and bathroom with a good price/quality balance

5.4. Step 4: finishes and presentation

Finally, work on:

• Neutral, light-coloured paint
• Consistent flooring throughout
• Lighting and storage

These are relatively small renovation budgets that can unlock a sale at asking price, or even a bidding situation when supply is limited.

6. Renovations, inflation and tax: don’t forget the context

Your renovation ROI calculation should account for:

• Annual inflation: rising material and labour costs, but also potential nominal house price growth
• Property tax revaluation: upgrades can eventually push your assessed value and tax bill higher
• Capital gains tax (for non-primary residences): part of the value increase may be taxed at resale

With mortgage rates around 3.6% and moderate inflation, well-targeted works can still be very profitable, but they must be benchmarked against a realistic investment rate (3–5% per year) and against the full cost of owning: notary fees, agency fees, borrower insurance, potential early repayment penalties (often capped at 3% of the remaining balance or 6 months’ interest).

Conclusion: renovations pay off when you treat them like investments

The renovations with the best resale ROI tend to be:

• Energy upgrades (DPE/energy rating, heating, insulation)
• Kitchen and bathroom modernisation
• Layout optimisation (extra room, better circulation)
• A well-planned, full cosmetic refresh

Highly personal or over-luxury projects are usually poor value if your main objective is resale profit. As always, the right choice between buy or rent, and the scale of your renovation budget, depends on your profile, timeframe and local market. This article is educational only and does not constitute personalised financial advice.

To see the real impact of a montant travaux of €10,000, €30,000 or €50,000 on your future net worth compared with staying a tenant and investing that same money, simulate your situation on buy-or-rent.net.