Where do you start when renovating an older house in Luxembourg?
By Yacine Sahnoune, founder of renov.lu
To renovate an older house in Luxembourg, start with a diagnosis (approved energy advisor and energy performance certificate), then deal with the structure and roof, the networks, insulation and windows, before heating and finishes. A full renovation costs €1,150 to €2,500/m² excl. VAT, i.e. €138,000 to €300,000 excl. VAT for 120 m².
- Order: diagnosis → structure and roof → networks → insulation and windows → heating → finishes
- 120 m² house: €30,000–90,000 (refresh), €138,000–300,000 (full), excl. VAT; partial: €750–1,250 per treated m²
- Energy advice: required for the Klimabonus from 2 renovated elements; grant of €1,700, €2,000 until 30 June 2027
- Approval in principle: before starting insulation, windows or MVHR; for a heat pump, apply after installation
- 1975 house example: €68,200 excl. VAT of energy works, €28,640 of Klimabonus, €9,548 of VAT saved
- Duration: 3 to 6 months on site for a full renovation of 100 to 150 m²
Get your house renovation priced
Describe the house and the planned works: we forward your request to companies established in Luxembourg, 3 free quotes, no obligation.
Where to start: diagnosing the house
The first useful spend is not a works quote but a diagnosis: the state of the structure, roof, damp and networks sets the order and the budget. For the Klimabonus, an approved energy advisor and a pre-works energy performance certificate (EPC) are required as soon as more than one element is renovated.
| What to check | Warning signs | Who, and how much |
|---|---|---|
| Roof structure and covering | Slipped tiles, damaged timber, leak marks | Carpenter or roofer; roof-structure survey €300 to €800 |
| Damp | Saltpetre, mould, cellar smell | Diagnosis before any insulation |
| Electrics | Fuse board, no residual-current device, unearthed sockets | Electrician |
| Plumbing | Lead or galvanised steel pipes | Plumber |
| Asbestos | Corrugated sheets, artificial slates, tile adhesives, floor tiles | Pre-works survey; removal €1,000 to €4,000 for a typical job |
| Energy performance | High heating bills, low EPC class | EPC (free pricing, about €500 to €600 for a house) and approved energy advisor |
Klima-Agence’s basic advice is free (8002 11 90) but does not replace the approved advisor required for the Klimabonus. That approved advice is subsidised at €1,700, or €2,000 if the approval in principle is requested before 30 June 2027, up to its actual cost: see our energy advisor page. For asbestos, see asbestos: survey and removal.
In which order should you renovate a house?
The order that avoids paying twice: first what protects the house (structure, roof), then what runs inside the walls (networks), then the envelope (insulation, windows, ventilation), then heating sized for the insulated house, and finally the finishes. The full schedule (quotes, approvals, works, handover) is set out in our guide to the steps of a home renovation in Luxembourg.
Diagnosis, grants and permits
Renovation concept, quotes, Klimabonus approval in principle for insulation, windows and MVHR, municipal permit if the facade or volume changes. None of these works starts before the approval in principle.
Structure, roof, damp
A leaking roof ruins the insulation beneath it. Use the re-roofing to insulate from the outside. With a heated attic, the Klimabonus then requires replacing roof windows older than 10 years with a Uw above 1.4 W/m²K.
Concealed networks
Electrics, plumbing and drains are redone before linings and screeds: reopening them after the finishes costs twice.
Envelope: insulation, windows, ventilation
Roof or loft floor, walls, windows. New windows in uninsulated walls encourage condensation: to subsidise them, the Klimabonus requires an insulated wall (U ≤ 0.85 W/m²K) or MVHR.
Heating
A heat pump is sized on the needs of the insulated house; sized before insulation, it is oversized and more expensive. Hydraulic balancing is a Klimabonus condition.
Finishes
Partitions, floors, bathroom, kitchen, painting: last, when nothing else has to go into the walls. Details: order and cost of finishing works, room by room.
Have the energy advisor draw up the renovation concept from the start: it sets the order of the stages, and the Klimabonus class bonus (+20% to +50% on the insulation grant) can be earned in stages if the EPC before and after proves a gain of at least 2 classes.
Renovating a 1960s, 70s or 80s house in Luxembourg
A house from the 1960s to 80s that has never been renovated usually combines missing or very thin insulation, single glazing or first-generation double glazing and an oil or gas boiler: the envelope is the priority, and asbestos must be checked for before any demolition.
| Weak point | 1960s | 1970s | 1980s |
|---|---|---|---|
| Insulation | None | None or very thin | First mineral wool, low thicknesses |
| Windows | Single glazing, wood or steel | Single glazing, first double glazing | First-generation double glazing |
| Heating | Oil, high-temperature radiators | Oil or gas | Gas or oil |
| Electrics | Often no RCD or earth | Usually to be redone | To be checked |
| Asbestos | Possible (fibre cement, flues) | Frequent (sheets, adhesives, floor tiles) | Possible |
| Priorities | Roof, walls, heating, electrics | Roof, walls, windows, heating | Windows, heating, extra insulation |
For these houses, coherent stages are often more realistic than one big project: roof and attic, then facade and windows, then heat pump. A terraced house has its own constraints (party wall, uniform facades): see renovating a terraced house.
How much does it cost to renovate a house?
The budget is calculated with the three ranges from our renovation cost per m² page: €250 to €750/m² excl. VAT for a refresh, €750 to €1,250/m² excl. VAT of treated area for a partial renovation and €1,150 to €2,500/m² excl. VAT for a full renovation. Overall budget, duration and grants for a project: see our guide to home renovation in Luxembourg.
| Scope | Cost per m² excl. VAT | 120 m² house | 150 m² house |
|---|---|---|---|
| Refresh | €250 – 750 | €30,000 – 90,000 | €37,500 – 112,500 |
| Partial renovation | €750 – 1,250 per treated m² | 40 m² treated: €30,000 – 50,000 | 60 m² treated: €45,000 – 75,000 |
| Full renovation | €1,150 – 2,500 | €138,000 – 300,000 | €172,500 – 375,000 |
What pushes a house to the top of the range: a roof to redo (€180 to €400/m² depending on the material), a facade to insulate, asbestos removal, structural repairs and location (Luxembourg City is generally 10 to 20% more expensive). Add a 10% contingency in a recent house, 20 to 30% in a pre-1980 house and, if an architect coordinates, 8 to 15% of the works cost excl. VAT.
Worked example: a 1975 house renovated in 2026-2027
A 1975 house, 140 m² of living space, oil-heated, whose owner insulates the facade, replaces the windows and installs a heat pump. Assumptions: mid-range market prices, approval in principle requested and heat pump ordered before 30 June 2027, home over 10 years old used as a main residence.
| Item | Cost excl. VAT | Klimabonus | Grant calculation |
|---|---|---|---|
| External facade insulation, rock wool (standard II), 180 m² | €34,200 | €14,400 | €80/m² × 180 m² (42% of cost, under the 60% cap) |
| Triple-glazed windows (Ug ≤ 0.6), 28 m² | €14,000 | €2,240 | €80/m² × 28 m² |
| Air-to-water heat pump replacing the oil boiler | €20,000 | €12,000 | House flat rate, ordered before 30 June 2027 |
| Total | €68,200 | €28,640 |
3% VAT: €2,046 instead of €11,594 at 17%, i.e. €9,548 saved. Net cost: 68,200 + 2,046 − 28,640 = €41,606. Possible extras: €1,500 if the oil tank is removed by a specialist company, the energy advice (€2,000, up to its cost) and a 20 to 50% bonus on the insulation grant if the house gains at least 2 classes. Redo the calculation for your house with the renovation simulator.
Which grants apply to renovating a house in Luxembourg?
A renovated house combines 3% VAT on all eligible works and the Klimabonus on the energy part; the social top-up (10 to 100% of the Klimabonus depending on income) and the Klimaprêt complete the financing. Amounts for a single-family house (in brackets: applications until 30 June 2027):
- Insulation: €35–130/m² against the outside (€40–155), €20–65/m² against an unheated space (€25–75), at most 60% of the cost excl. VAT; nothing for a conventional fossil insulant
- Windows: €70/m² (€80/m²), glazing Ug ≤ 0.6 W/m²K
- MVHR: €60/m² of energy reference area (€70), at most €9,000 (€10,500), only with energy advice
- Heat pump: air-to-water €10,000 (€12,000), geothermal €12,000 (€14,000) when replacing fossil or direct electric heating; up to +€2,000 to adapt the heat distribution; +€1,500 for removing the oil tank
- Klimaprêt: the State pays 1.5% interest per year on up to €100,000 over up to 15 years; State guarantee up to €50,000
Details by type of works and the forms are on our grants and Klimabonus page; VAT conditions on our 3% VAT page.
Which permits do you need to renovate a house?
For a house, the municipality decides: renovating or insulating a facade or roof without a significant change in appearance is exempt under the model regulation recommended to municipalities, but an extension, raising the roof, a dormer or changes to openings need at least a declaration, often a permit from the mayor.
- External insulation: the model regulation allows a derogation of up to 0.50 m on building lines, setbacks and heights
- Heat pump outdoor unit: at the rear or side, at least 2.00 m from the boundary under the model regulation; for the Klimabonus, at most 40 dB(A) at the neighbouring buildable plot’s boundary, or a sound power of 48 to 55 dB(A) depending on output
- Protected area or listed building: generally a permit, plus approval from the Minister of Culture for a listed building
All cases are on our building permit and works declaration page.
The most expensive mistakes
| Mistake | Cost |
|---|---|
| Starting insulation or windows before the approval in principle | Grant lost: €14,400 for the facade and €2,240 for the windows in the example above |
| Choosing a conventional fossil insulant (polystyrene, polyurethane) | No grant, unless over 50% recycled content, a wall against the ground or a green roof |
| Installing the heat pump before insulating | Oversized unit, dearer to buy and less efficient |
| Replacing windows without insulating walls or ventilating | Risk of condensation and mould; no window Klimabonus without an insulated wall or MVHR |
| Demolishing without an asbestos survey | Site stopped, decontamination at the owner’s expense |
| Starting without a financial reserve | Works blocked at the first surprise: keep 20 to 30% of the budget in a pre-1980 house |
To avoid bad surprises with contractors (deposit, quotes, insurance), read our guide to choosing a renovation company.
Request quotes to renovate your house
Describe your house (year, area, heating) and the planned works: we forward your request to companies established in Luxembourg, business permit checked. You receive 3 quotes, free and without obligation.
Renovate your house, step by step
Roof, insulation, windows, heating or full renovation: one request, comparable quotes.
Frequently asked questions about renovating an older house
Should you insulate before installing a heat pump?
Yes, in an older house insulate first or at least at the same time. A heat pump is sized on the house’s heat demand: sized before insulation, it is oversized, more expensive and runs less well. If the heat pump has to come first, have it sized for the house as it will be after the planned insulation works.
Is an energy advisor mandatory to renovate your house?
To obtain the Klimabonus, yes as soon as the renovation covers more than one element or includes MVHR. For a single element, the company must be approved or an advisor must support the works, and no advice is required for a heat pump alone. Approved advice is subsidised at €1,700, or €2,000 if the approval in principle is requested before 30 June 2027.
How much does it cost to energy-renovate a 1970s house?
For a 140 m² house built in 1975, insulating the facade, replacing the windows and installing a heat pump costs about €68,200 excluding VAT. The Klimabonus covers about €28,640 if applied for before 30 June 2027, and 3% VAT avoids €9,548 of VAT: about €41,600 remains for the owner, before any bonuses.
Can you live in your house during a full renovation?
Rarely during the heavy phases: demolition, networks, screeds and a heating change make the house hard to live in for several weeks. A staged renovation, however, lets you stay by freeing one floor at a time. Budget for temporary housing and do not tie its end to the announced completion date.
Is the Klimaprêt a zero-interest loan?
No. The Klimaprêt is a standard bank loan on which the State pays 1.5% interest per year, on up to €100,000 over up to 15 years, within 10% of the capital. It has no income condition but requires a Klimabonus already granted and a home over 10 years old that becomes the main residence no later than 3 years after the works start.
Can you renovate your house in stages without losing the grants?
Yes. The Klimabonus accepts insulation, window and MVHR works invoiced until 31 December 2035, provided a first approval-in-principle application is filed before 31 December 2030 and each approval is requested before the stage concerned. The energy-class bonus can also be earned in stages, if an energy performance certificate before and after proves a gain of at least 2 classes.