Roof windows Velux and dormers in Luxembourg: prices, installation and authorizations 2026
Converting attics in Luxembourg requires a well-thought-out project to optimize natural lighting and aesthetics. Velux windows, dormers (lucarnes), small roof windows: each option offers distinct advantages. This comprehensive guide helps you understand window types, realistic prices 2026, mandatory administrative procedures, safety standards, selection criteria and installation steps to transform your attic into bright and welcoming rooms.
Converting your attic in Luxembourg
Get detailed quotes from certified craftspeople and explore optimal lighting solutions for your roof configuration.
Converting your attic in Luxembourg
Get detailed quotes from certified craftspeople and explore optimal lighting solutions.
Types of roof windows and dormers in Luxembourg
Classic Velux windows (manual)
- Simple installation, adapts to existing roof
- Cost: €800–2,000 supply, €300–600 installation
- Optimal price-quality for small to medium budgets
- No permit generally required
Motorized Velux windows
- Cost: €1,500–3,000 supply, €400–800 installation
- Wireless remote, smart home integrable
- Automatic rain/wind closing possible
Dormers (lucarnes)
- Cost: €3,000–12,000 fully installed
- Increased living space (+2 to 5 m²), standard vertical window
- 3–8 weeks depending on complexity
- Requires planning permit
Limited budget (€2,000–5,000): choose 1–2 motorized Velux. Higher budget (€5,000+) and want to maximize space/light: opt for 1–2 small dormers combined with Velux.
Velux windows: advantages and limitations
Popular Velux ranges in Luxembourg
| Velux range | Supply + installation | Note |
|---|---|---|
| Velux Comfort Standard (manual) | €1,100–€1,500 | Single or entry-level double glazing |
| Velux Double-glazed (thermal) | €1,400–€2,200 | Enhanced thermal insulation — eligible 3% VAT |
| Velux Performance motorized | €1,800–€2,600 | Remote, rain/wind sensors, smart home ready |
Some carpenters offer Velux without thermal insulation (single glazing). In Luxembourg, ALWAYS prefer double or triple glazing for heating savings (3% VAT possible on thermal renovation).
Dormers (lucarnes): the premium solution
Detailed costs of a dormer
- New framing: €1,500–3,000
- Covering (slate, tile): €800–2,000
- Vertical window: €600–1,500
- Insulation/lining: €500–1,500
- Labor: €1,500–4,000
- Average total: €5,000–12,000
Comparison table of attic lighting solutions
| Criterion | Standard Velux | Motorized Velux | Dormer |
|---|---|---|---|
| Total cost | €1,100–€1,600 | €1,800–€2,600 | €5,000–€12,000 |
| Installation | 1–2 hours | 2–3 hours | 3–8 weeks |
| Permit required | No | No | Yes (planning) |
| Amount of light | Good | Good | Excellent |
| Living space | Unchanged | Unchanged | +2–5 m² |
| Property value | +2–5% | +3–7% | +15–25% |
Prices and installation costs 2026 in Luxembourg
| Type | Supply | Installation | Total incl. VAT |
|---|---|---|---|
| Standard Velux (manual) | €600–1,000 | €500–800 | €1,300–2,300 |
| Motorized Velux | €1,000–1,500 | €500–1,000 | €1,800–3,100 |
| Dormer (complete) | €3,900–7,500 | €1,500–3,500 | €6,000–13,500 |
Permits and compliance in Luxembourg
Velux windows generally do not require a building permit. A dormer significantly modifies the building envelope and requires authorization from municipal authorities, including consultation of the PAG, filing plans and stability calculations (4–8 weeks processing).
Use an architect or project manager for any dormer project. This ensures administrative and technical compliance, and protects your investment.
Thermal and sound insulation
Insulating windows without insulating attics is ineffective. Always prioritize attic (roof) insulation BEFORE windows. This accounts for 60–70% of thermal losses.
Detailed cost table 2026 in Luxembourg
| Type of work | Total cost incl. VAT | Included / note |
|---|---|---|
| Standard Velux single glazing (78 × 140 cm) | €1,100–€1,500 | Supply + installation — labor 30–40% of total |
| High-performance double-glazed Velux | €1,600–€2,300 | Supply + installation — eligible 3% VAT |
| Motorized Velux with smart home sensors | €2,200–€3,500 | Supply + installation — auto rain/wind closing |
| Standard dormer (1.2 m × 1 m) | €5,500–€8,500 | Full turnkey — framing, roofing, integrated window |
| Large dormer (≥ 1.5 m × 1.5 m) | €9,000–€15,000 | Full turnkey — increased living area |
| Replace existing Velux (removal + reinstall) | €800–€1,300 | Labor only — existing structure reused |
Selection guide: Velux vs Fakro vs Roto in Luxembourg
| Criterion | Velux | Fakro | Roto |
|---|---|---|---|
| Average price (single window) | €1,200–€1,600 | €950–€1,300 | €1,100–€1,400 |
| Thermal performance Uw | Very good (up to 0.89) | Good (up to 1.0) | Very good (up to 0.95) |
| Luxembourg availability | Excellent | Good | Very good |
| Service life | 25–35 years | 20–30 years | 25–35 years |
| Value for money | Excellent (premium) | Very good (budget) | Excellent (high-end) |
3% VAT relief and Klimabonus subsidies
The 3% VAT applies to all roof window installation and replacement work when: building completed at least 10 years ago, approved AED contractor, double glazing minimum, direct invoicing at reduced rate. Savings example: €1,800 ex-VAT installation → save €252 vs standard 17% VAT.
RT standards and thermal performance in Luxembourg
To be eligible for 3% VAT, your roof window must meet Uw ≤ 1.4 minimum. For low-energy building projects, prioritize Uw ≤ 1.0.
Frequently asked questions
Velux or dormer: what to choose?
Limited budget (€2–5K): Velux. Medium budget (€5–8K): combination. Higher budget (€8K+): dormer for max space/light.
Can a Velux cause leaks?
Well-installed Velux: very rare. Risk if insufficient installation, worn joints, water/snow accumulation. Regular maintenance prevents leaks.
Can you combine Velux + dormer?
Yes, intelligent combination: 1 small dormer street-side (visual impact) + 1–2 Velux garden-side (extra light).
Reduced VAT possible?
Yes, 3% VAT if energy improvement in primary residence. Double-glazed Velux + attic insulation eligible.
Winter dormer installation possible?
Discouraged. Humidity, cold, roof snow risk. Prefer spring/summer. Minimum 8–10 weeks total timeline.
Ready to start your project?
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