When a Luxembourg homeowner asks whether a renovation will "pay back at sale," the honest answer depends on three variables: the type of work, the property's current condition, and the location. A new kitchen in Belair returns differently than the same kitchen in Wiltz; energy upgrades on a Class F house return more than on a Class C house.
This article gives the 2026 numbers — cost ranges and value-uplift estimates — drawn from valuations completed across Luxembourg over the past 24 months. The categories are ranked by ROI, best to worst.
Tier 1: Energy upgrades (often 80–120% ROI)
Since 2023, energy class has become a major price driver in Luxembourg. Upgrading the energy class of a property is consistently the highest-return renovation category — but only if it actually changes the certificate class.
Insulation (façade, attic, roof)
- Cost: €40,000–€90,000 for a typical 150 m² house
- Energy class shift: typically 1–2 letters (e.g., F→D, D→C)
- Value uplift: €60,000–€110,000 in suburban locations, €80,000–€150,000 in Luxembourg City
- ROI: 100–130%
The single highest-ROI renovation in Luxembourg right now. The reason: the discount on F/G properties has widened to 10–15%, so eliminating it is worth a lot.
Heating system replacement (heat pump)
- Cost: €18,000–€35,000 (incl. removal of old oil/gas boiler)
- Often combined with insulation to maximise class shift
- Value uplift: €25,000–€50,000 standalone, but synergistic with insulation
- ROI: 100–130% combined with insulation; 60–80% standalone
A heat pump alone rarely shifts the energy class enough to justify itself, but combined with even modest insulation, it does.
Triple-glazed windows
- Cost: €25,000–€45,000 for full house replacement
- Value uplift: €15,000–€35,000 standalone; substantially more in combination
- ROI: 60–80% standalone; 100%+ in package
Always do windows in combination with other energy works, never standalone — the renovation disruption cost is similar either way, but the bundled ROI is much better.
Tier 2: Kitchen and bathroom (50–80% ROI)
These are the rooms buyers judge most harshly. A dated kitchen or bathroom can knock 5–8% off a home's perceived value, even when nothing structural is wrong.
Kitchen replacement
- Cost: €15,000–€35,000 for a quality mid-range kitchen including appliances
- Value uplift: €18,000–€30,000
- ROI: 70–90% if the existing kitchen was 15+ years old; 30–50% if it was newer
The trick: don't over-invest. A €40,000 designer kitchen rarely returns more value than a €25,000 quality kitchen on a sub-€1.5M property. Buyer perception saturates above a threshold.
Bathroom renovation
- Cost: €8,000–€18,000 per bathroom
- Value uplift: €6,000–€12,000 per bathroom
- ROI: 60–80%
For older houses with two or three dated bathrooms, doing all of them in one project is more efficient than staging.
Tier 3: Floor area additions (40–70% ROI)
Adding livable surface area is generally positive but more capital-intensive than cosmetic upgrades.
Attic conversion (loft / combles aménagés)
- Cost: €40,000–€90,000 for converting 30–50 m² into livable space (insulation, dormer windows, electricity, partial bathroom)
- Value uplift: €60,000–€140,000 (depending on commune €/m²)
- ROI: 100–150% in central communes; 60–90% in rural
For Luxembourg City and first-ring suburbs, attic conversion is often the single best value-creating renovation, comparable to or better than energy upgrades.
Cellar conversion (basement living space)
- Cost: €30,000–€60,000
- Value uplift: €25,000–€50,000 (cellar space valued at 50–60% of above-ground €/m²)
- ROI: 60–90%
Less impactful than attic conversion because cellar space carries a perceived discount even after conversion.
Extension (extension de plain-pied)
- Cost: €2,000–€3,500 per added m² of high-quality living space (varies hugely by complexity)
- Value uplift: 70–110% of the local €/m² for added space
- ROI: 50–90%
Extensions face two ROI killers: planning permission delays/refusals, and the construction-cost inflation in Luxembourg over the past 3 years (now ~4–5% annually). Quote prices have a short shelf life.
Tier 4: Bedrooms and useful additions (30–50% ROI)
Adding a bedroom (e.g., dividing a large room)
- Cost: €3,000–€8,000 (partition, door, possibly ventilation)
- Value uplift: €15,000–€30,000 for going from 3 to 4 bedrooms in family-suitable houses
- ROI: 200–400%
The highest single-action ROI in this entire list — but only if the property realistically supports the additional bedroom (i.e., the rooms remain large enough to be functional).
Home office / dedicated workspace
- Cost: €5,000–€15,000 for converting a small space
- Value uplift: €10,000–€20,000 in a post-2020 market that values WFH-friendly homes
- ROI: 80–130%
Worth doing for properties that lack a defined office; not worth it if the home already has a flexible spare room.
Balcony / terrace upgrade
- Cost: €5,000–€20,000
- Value uplift: €8,000–€20,000 in apartments; less in houses
- ROI: 60–100% in apartments; 30–50% in houses
Apartment buyers heavily value outdoor space; house buyers mostly care about the garden, not the terrace.
Tier 5: Cosmetic / superficial (40–70% ROI on small spends)
Repainting (interior)
- Cost: €4,000–€10,000 for a 150 m² house
- Value uplift: €5,000–€10,000 in apparent condition; aids faster sale
- ROI: 80–120% if the original paint was clearly worn; near-zero if it wasn't
The cheapest pre-sale cosmetic improvement. Always consider before listing.
Floor refinishing or replacement
- Cost: €4,000–€20,000 depending on material
- Value uplift: €5,000–€15,000
- ROI: 50–80%
Refinish if possible (sanding/varnishing wooden floors); replace only if the existing material is genuinely beyond saving.
Garden landscaping
- Cost: €3,000–€20,000
- Value uplift: €4,000–€15,000
- ROI: 60–90%
Modest landscaping (lawn, simple beds, perhaps a path) helps significantly in photographs and viewings. Heavy hardscaping (designer terraces, water features) rarely returns its cost.
Tier 6: Low or negative ROI
Swimming pool (in-ground)
- Cost: €40,000–€100,000+ for installation; €1,500–€3,000/year for maintenance
- Value uplift: €15,000–€35,000
- ROI: 20–40%
Swimming pools are an emotional purchase, not a financial one. They limit your buyer pool (some buyers actively avoid them) and impose ongoing costs.
Designer architecture (custom features, atriums, oversized rooms)
- Cost: variable, often €100,000+
- Value uplift: rarely more than 50% of cost
- ROI: 20–60%
Highly personal taste rarely translates into higher resale value. Buy a home you love, but don't expect the next buyer to share your specific vision.
Solar panels (roof)
- Cost: €15,000–€30,000
- Value uplift: €5,000–€15,000 (solar is increasingly priced in but still discounted vs. cost)
- ROI: 40–70%
Improving steadily as energy prices rise, but still below cost on most properties. Combined with broader energy upgrades, the package ROI improves.
Garage conversion to living space
- Cost: €15,000–€30,000
- Value uplift: -€5,000 to +€10,000 (sometimes negative — buyers want garages)
- ROI: variable, often poor
In Luxembourg, off-street parking is heavily valued. Converting a garage usually loses more than it gains.
How to think about renovation strategically
Three principles emerge from the data:
- Energy class drives the biggest returns. If your property has a poor energy class (D or below), this is almost always the highest-return work, especially in Luxembourg City and first-ring suburbs.
- Adding bedrooms and converting attics outperform pure renovations. Increased livable space at scarce-land Luxembourg prices delivers high ROI.
- Cosmetic work pays best on tired properties. A tired property gains a lot from light renovation; a well-maintained property gains little from more spending.
A timing consideration: renovate before or after listing?
Ideally before, but with two caveats:
- Time on market matters. A renovation that takes 6 months ties up your capital. If interest rates are dropping, this can offset the value gain.
- Buyer preferences differ. Some buyers prefer to renovate to their own taste — and pay roughly fair value for an unrenovated property. Others want move-in-ready and pay a 5–10% premium for it.
For mid-range Luxembourg properties (€800K–€1.5M), pre-listing renovation usually wins. For ultra-luxury (€2M+), the buyer often prefers to customise.
Closing thought
Renovation in Luxembourg is rarely about adding total spending — it's about adding the right spending. The highest-ROI works are usually energy upgrades, attic conversions, and selective bedroom additions. The lowest-ROI works are swimming pools and designer custom features.
For a renovation impact analysis on your specific property — modeling current value, post-renovation value, and ROI for each major option — request a no-obligation quote. The report quantifies which renovations make economic sense and which don't.