Heat Pump in Luxembourg:
Complete Guide 2026
A heat pump produces 3 to 5× more energy than it consumes and can cut your heating bills by 50% or more. In Luxembourg, it benefits from Klimabonus grants of up to €9,500 and a reduced 3% VAT rate.
How does a heat pump work?
A heat pump captures thermal energy from the environment (air, ground or water) and transfers it to your home via a refrigerant circuit. It doesn’t create heat — it moves and amplifies it. That’s why it’s so efficient.
The principle is based on a 4-step thermodynamic cycle: evaporation (the refrigerant absorbs heat from the outside source), compression (an electric compressor heats the gas — this is where electricity is consumed), condensation (the hot gas transfers its heat to your heating circuit), and expansion (the fluid cools and the cycle restarts).
COP and SCOP: measuring real efficiency
The COP (Coefficient of Performance) measures instantaneous efficiency. A COP of 4 means 1 kWh of electricity produces 4 kWh of heat — 400% efficiency. The SCOP (Seasonal COP) is the figure that truly matters: it measures average efficiency across the whole heating season. In Luxembourg (H1 climate zone), air-to-water heat pumps typically achieve a real SCOP of 3.5 to 4.5. Learn more: COP and SCOP guide.
In Luxembourg, temperatures drop below freezing for less than 5% of annual heating hours. The impact on the annual bill is limited, especially for inverter models that operate down to -20°C without activating the backup resistance. See: heat pump performance in cold winters.
Real-world efficiency by temperature: the 2026 verdict
Verdict, August 2026: in Luxembourg, a heat pump delivers 3 to 5 kWh of heat per kWh of electricity consumed. An air-to-water heat pump reaches a COP of 4 to 4.5 at +7 °C outdoors, and still 2 to 2.5 at −5 °C — and most of the Luxembourg winter sits between 0 and +7 °C.
| Outdoor temperature | COP air-to-water | COP ground-source | Situation in Luxembourg |
|---|---|---|---|
| > +7 °C | 4.0 – 4.5 | 4.5 – 5.5 | Optimal — spring, autumn |
| 0 °C to +7 °C | 2.5 – 3.5 | 4.0 – 5.0 | Good — mild winter, most of the season |
| −5 °C to 0 °C | 2.0 – 2.5 | 3.5 – 4.5 | Reduced — frequent cold spells |
| < −5 °C | 1.5 – 2.0 (+ backup) | 3.0 – 4.0 | Rare episodes |
On refrigerants: R410A has been banned for new installations since 1 January 2025 (EU Regulation 2024/573); R32 (GWP 675) and propane R290 (GWP 3, water up to 75 °C) are replacing it. Full grant details are on our heat pump grants in Luxembourg page.
COP and SCOP of a heat pump: what efficiency to expect in Luxembourg?
In August 2026 in Luxembourg, an air-to-water heat pump achieves a real-world SCOP of 3.2 to 4.5. The COP (EN 14511) measures instantaneous efficiency in laboratory conditions: 3 kW of electricity for 12 kW of heat = COP 4. The SCOP (EN 14825) is the seasonal average, computed over four reference temperatures (−7, +2, +7 and +12 °C) for the « average » European climate — Strasbourg’s, very close to Luxembourg’s. A catalogue COP of 4.5 typically translates into a field SCOP of 3.8 to 4.2, and the Oesling loses 5 to 10% of SCOP compared with the south of the country.
The COP is what determines Klimabonus eligibility:
| Heat pump type | Minimum COP for Klimabonus | Test regime |
|---|---|---|
| Air-to-water (incl. non-fossil hybrid) | COP ≥ 3.1 | A7/W35 |
| Ground-source brine/water | COP ≥ 4.3 | B0/W35 |
| Direct-expansion ground-source | COP ≥ 4.3 | E4/W35 |
The heat emitters matter as much as the machine: underfloor heating at 35 °C = SCOP up to 4.5+, high-temperature radiators at 55–65 °C = SCOP 3.0 to 3.6. The ETAS shown on the energy label equals SCOP ÷ 2.5 × 100: a SCOP of 4.0 gives 160%, versus ~94% for a gas condensing boiler. Estimate the SCOP achievable in your home with our heat pump simulator.
Types of heat pumps
There are three main families of heat pumps, each drawing on a different energy source:
1. Aerothermal (air-to-air or air-to-water) — the most common
They extract energy from outdoor air. Most common in Luxembourg due to simpler installation and lower upfront cost. SCOP 3.5–4.5. Cost: €8,000–€18,000 installed. Grants up to €9,500.
2. Geothermal (ground-to-water) — the most efficient
They use the stable ground temperature (~10°C year-round). SCOP 4.5–5.5. Cost: €25,000–€45,000. Grants up to €14,000. Requires significant excavation work.
3. Hydrothermal (water-to-water) — the least common
They exploit groundwater or watercourse heat. Excellent efficiency but heavily constrained by geological conditions and Luxembourg water use regulations.
| Type | Energy source | Avg. SCOP (LU) | Installation cost | Complexity |
|---|---|---|---|---|
| Aerothermal | Outdoor air | 3.5 – 4.5 | €8,000 – €18,000 | Low |
| Geothermal | Ground / subsoil | 4.5 – 5.5 | €25,000 – €45,000 | High |
| Hydrothermal | Groundwater | 4.5 – 5.0 | €20,000 – €40,000 | Very high |
→ Detailed heat pump operation guide · Sizing and power guide
Heat pump and domestic hot water in Luxembourg
In 2026, producing your hot water with a heat pump is 3 to 4 times more efficient than a classic electric water heater: COP of 2.5 to 4, meaning 50 to 70% less energy and €250 to €400 in yearly savings for an average family. Allow 40 to 60 L of hot water per person per day — a 200 to 300 L tank for a family of 4.
| DHW source | Annual consumption | Annual cost | CO₂ emissions |
|---|---|---|---|
| Heat pump (COP 3.0) | 1,500 – 1,800 kWh | €200 – €250 | 200 kg |
| Electric water heater | 3,500 – 4,200 kWh | €500 – €700 | 500 kg |
| Gas boiler | 2,500 – 3,000 kWh | €300 – €400 | 800 kg |
| Solar thermal | Near 0 kWh | €0 – €50 | 0 kg |
Two Luxembourg rules to know: domestic hot water must be kept at at least 55 °C (legionella prevention, weekly one-hour pasteurisation), and a standalone heat pump water heater is not eligible for the Klimabonus — only an air-to-water heat pump that also provides space heating is (up to €10,000 when replacing a fossil-fuel boiler), while the 3% VAT and Enoprimes remain available. For hot water alone, see our heat pump water heater guide, or request a heat pump quote for a combined heating + hot water solution.
Air-to-air vs air-to-water heat pump: which to choose in Luxembourg?
🌬️ Air-to-Air
- Blows heated (or cooled) air directly into rooms
- Best for: replacing electric radiators, apartments
- Lower upfront cost (from €5,000)
- Installation: 1–2 days
- Savings: ~30% vs direct electric heating
- Cannot produce domestic hot water
💧 Air-to-Water Recommended
- Heats the water in your existing heating circuit
- Best for: replacing gas/oil boilers in houses
- Higher upfront cost (from €10,000)
- Installation: 2–4 days
- Savings: up to 50% vs gas, 70% vs oil
- Can produce domestic hot water
- Maximum Klimabonus (up to €9,500)
In the vast majority of Luxembourg cases, the air-to-water heat pump is the most cost-effective solution for replacing a gas or oil boiler. It attracts the highest Klimabonus grants and delivers the best long-term savings. Detailed comparison: air-to-water vs air-to-air guide.
Air-to-water or air-to-air: the 2026 verdict in figures
Verdict, August 2026: after grants, an air-to-water heat pump often ends up cheaper net than an air-to-air multi-split. Air-to-water stacks the Klimabonus, Enoprimes (~€1,500), 3% VAT and municipal aid (up to €3,000) for a total that can exceed €15,000; the air-to-air heat pump is not eligible for the standard Klimabonus.
| Criterion | Air-to-water heat pump | Air-to-air (reversible) |
|---|---|---|
| Gross installation cost | €16,000 – €24,000 (100–150 m² house) | €1,500 – €3,500 (mono-split) / €3,500 – €8,000 (multi-split) |
| Combined grants | Up to ~€15,000 | 3% VAT only |
| Net cost after grants | From ~€5,000 – €9,000 | €1,400 – €7,700 |
| Seasonal COP (Lux.) | 3.0 – 3.5 | 2.5 – 3.2 as main heating |
| Lifespan / EPC impact | 15 – 20 years / +1 to +2 classes | 12 – 15 years / little or no gain |
Beware of air-conditioning sellers mentioning « Klimabonus grants » for an air-to-air unit: only one narrow exception exists (~€6,000 max, main heating without a hydraulic circuit replacing a fossil-fuel boiler), to be verified case by case. Full details on our heat pump grants in Luxembourg page.
Benefits of a heat pump in Luxembourg
Exceptional efficiency: up to 500%
Unlike boilers (efficiency <100%), a heat pump produces 3–5 kWh of heat per kWh of electricity consumed. Result: heating bills cut by 2 to 4 times depending on your current system.
Among Europe’s most generous grants
In Luxembourg 2026, Klimabonus covers up to €9,500 for an air-to-water heat pump, up to €14,000 for geothermal. Stackable with Enoprimes (~€1,500) and 3% VAT. See all heat pump grants 2026.
Energy passport class jump
Replacing an oil boiler with an air-to-water heat pump in a well-insulated home typically gains 2–3 classes on the energy passport, directly increasing property value.
Heating AND reversible air conditioning
Most modern heat pumps are reversible: they cool your home in summer without additional installation — a major advantage over standard air conditioning systems.
CO₂ emission reduction
Versus a gas boiler, a heat pump on the Luxembourg grid reduces CO₂ emissions by 30–50%. Combined with solar panels, you can reach near-zero emissions for your heating.
Long lifespan and low maintenance
A well-maintained heat pump lasts 15 to 20 years. Annual maintenance is simple and inexpensive compared to boiler servicing. Learn more about maintenance.
Heat pump limitations: what to know
Limitation 1: flow temperature of the heating circuit
A heat pump works best with a low flow temperature (35–45°C), ideal for underfloor heating or low-temperature radiators. With old high-temperature radiators (60–70°C), COP drops to 2.0–2.5. Options: replace radiators with low-temperature models, or use a hybrid system. Heat pump and underfloor heating: the ideal combination.
Limitation 2: the home must be well-insulated
A heat pump in a poorly insulated home runs continuously, degrading SCOP and potentially tripling electricity bills. Golden rule: insulate first, then install the heat pump.
Limitation 3: large areas need adequate power
1 kW of heat pump capacity covers 10–15 m² (in an insulated home). A precise EN 12831 heat loss calculation is essential.
Limitation 4: apartments and co-owned buildings
Installing a heat pump in an apartment or co-owned building requires owners’ agreement and may need municipal permission. Luxembourg regulations also impose acoustic constraints.
Never start heat pump installation before obtaining the Klimabonus agreement in principle from Agence Klima. Without this, you forfeit all Klimabonus grants. Your certified installer handles this step for you.
What about deep cold? The Luxembourg winter in figures
Verdict, August 2026: deep cold below −10 °C accounts for less than 3% of winter hours in Luxembourg (MeteoLux data 1990–2024: December–February average of 0 to 5 °C, usual lows of −5 to −8 °C). A properly sized heat pump delivers 85 to 92% of the annual heat, with the backup covering the remaining 8 to 15%.
| Temperature range | Winter frequency (Lux.) | Operating mode | Heat pump COP |
|---|---|---|---|
| +7 °C to −2 °C | ~80% of the time | Heat pump alone — backup off | 3.0 – 4.0+ |
| −2 °C to −10 °C | 15 – 18% of the time | Heat pump + backup (bivalent) | 2.0 – 3.0 |
| Below −10 °C | < 2 – 3% of the time | Backup as main source | 1.5 – 2.0 |
Defrost cycles (5 to 10 min, 1 to 3 times a day in a typical winter) account for less than 2% of winter time and cost less than 1 °C indoors. The optimal bivalence point sits between −2 and −5 °C; the models to compare on this criterion are in our heat pump brand comparison.
Insulation: the essential prerequisite for any heat pump
The Luxembourg Klimabonus itself requires a minimum COP of 3.1 (A7/W35 conditions) — only sustainably achievable in a well-insulated home.
| Home EPC class | Real SCOP (air-to-water HP) | Annual heating cost (120 m²) |
|---|---|---|
| A / B (well insulated) | 4.0 – 4.5 | €550 – €800 |
| C / D (partial insulation) | 3.2 – 4.0 | €800 – €1,400 |
| E / F (little insulation) | 2.5 – 3.2 | €1,400 – €2,500 |
| G (energy-inefficient) | 2.0 – 2.5 | €2,500 – €4,000 |
→ Insulation as a heat pump prerequisite · Complete insulation guide
Is your home ready for a heat pump? Simulate your current EPC class and recommended works before installation.
Simulate my project →What minimum energy class before installing a heat pump?
Verdict, August 2026: class C minimum (under 200 kWh/m²/year), class B recommended. In a poorly insulated house, the COP drops from 3–4 to 1.5–2, the lifespan falls from 15–20 years to 10–12 years and the payback exceeds 20 years. A heat pump’s profitability depends 80% on insulation, 20% on the type of heat pump.
| EPC class | Consumption (kWh/m²/yr) | Heat pump compatibility | Recommended action |
|---|---|---|---|
| A – B | < 100 | Optimal — COP 3.5–4.5 | Install the heat pump directly |
| C | 100 – 200 | Viable — COP 2.8–3.2 | Insulate roof + windows first |
| D – E | 200 – 400 | Not advised — COP < 2.5 | Renovate roof, windows, walls first |
| F – G | > 400 | Not profitable | Full renovation required |
Insulating first cuts heating needs by 40 to 60%, allows a heat pump 30 to 40% cheaper to buy and brings the payback down to 8–12 years. Test the effect of your EPC class in the heat pump simulator.
Heat pump prices and grants in Luxembourg 2026
| Heat pump type | Installation cost 2026 | Klimabonus grant | Estimated net cost |
|---|---|---|---|
| Air-to-air (monosplit) | €5,000 – €8,000 | ~€2,500 | ~€2,500 – €5,500 |
| Air-to-water (boiler replacement) | €12,000 – €20,000 | Up to €9,500 | ~€4,000 – €12,000 |
| Geothermal (vertical probes) | €25,000 – €45,000 | Up to €14,000 | ~€12,000 – €32,000 |
For a 130 m² home replacing an oil boiler with an air-to-water heat pump, payback typically falls between 7 and 10 years. See the complete heat pump ROI analysis.
→ Heat pump prices and grants guide 2026 · Heat pump grant details
Calculate your real heat pump cost after grants
Every project is unique. Simulate your personalised Klimabonus grant in 2 minutes or request a precise quote from a certified installer.
Heat pump profitability in Luxembourg: real 2026 payback
In August 2026, a kWh of heat produced by an air-to-water heat pump (COP 3.2) costs about 8.06 cents — 18% less than heating oil (9.85 ct) and 25% less than gas (10.8 ct), based on the 2026 integrated electricity price of ~25.8 ct€/kWh (state measures from 1 January 2026, Ministry of the Economy). After grants, subsidies cover 69 to 81% of the gross cost:
| House profile | Net cost after grants | Annual saving | Payback | Cumulative 20-yr gain |
|---|---|---|---|---|
| A — 120 m², EPC E–F, oil | ~€6,180 | €444/yr | ~13.9 yrs | +€2,700 |
| B — 150 m², EPC D, gas (most common case) | ~€6,920 | €1,053/yr | ~6.6 yrs | +€14,140 |
| C — 130 m², EPC C, gas | ~€3,480 | €888/yr | ~3.9 yrs | +€14,280 |
Since 1 January 2026, the Klimabonus third-party payment lets the approved installer deduct the grant directly from the invoice, and the minimum-age condition for the replaced boiler has been abolished. Paired with 6 kWp of solar PV, profile B’s saving rises to €2,253/year with over €30,000 net gain over 20 years. On the property side, gaining 2 EPC classes (D → B) adds 10 to 15% to a home’s value. Work out your own payback with the heat pump simulator or request a free quote.
Heat pump installation steps in Luxembourg
Thermal study and sizing
A certified expert performs a building thermal study (EN 12831 standard) to determine the required capacity. This step conditions everything else and is often combined with the energy audit required for Klimabonus.
Klimabonus agreement in principle
Before any work commitment, your installer submits the agreement request to Agence Klima. Without prior agreement, you lose all Klimabonus grants. Processing time: typically 2–6 weeks.
Removal of existing heating system
The old boiler is removed and hydraulic circuits are cleaned. If needed, radiators are replaced with low-temperature models or underfloor heating is installed.
Heat pump installation and connections
Outdoor unit placed on anti-vibration supports. Penetrations through the façade allow refrigerant and hydraulic connections between units. Heat pump connected to dedicated electrical circuit and heating network.
Commissioning, settings and tests
Installer charges refrigerant, programmes weather-compensated control (essential for efficiency), calibrates the heating curve and performs functional tests. Commissioning typically takes half a day.
Post-installation inspection + grant application
An expert issues a new energy passport. Your installer then assembles the Klimabonus settlement file. Payment delay: generally 2–6 months.
For an air-to-water heat pump replacing a boiler: 2–4 working days on site, but the complete process (audit → agreement → works → payment) takes 3–6 months. Plan your project outside the heating season if possible.
Heat pump maintenance and lifespan
A well-maintained heat pump lasts 15 to 20 years. Annual professional maintenance is recommended (often required for warranty) and includes: filter and outdoor unit heat exchanger cleaning, refrigerant charge check, hydraulic circuit pressure check, weather compensation settings review, and electrical safety checks.
Average annual heat pump maintenance cost: €150–€300 — about 5 times less than a gas boiler service contract. More on heat pump maintenance and lifespan.
→ Compare: Replacing a gas boiler with a heat pump · Replacing an oil boiler with a heat pump
Essential heat pump guides
Specific use cases
To combine with the heat pump
Frequently asked questions about heat pumps in Luxembourg
How efficient is a heat pump compared to a boiler?
A heat pump is 3 to 5 times more efficient than a boiler. For 1 kWh of electricity consumed, it produces 3–5 kWh of heat (COP 3–5), versus ~0.92 kWh of heat per kWh of gas in a condensing boiler. In practice, replacing an oil boiler with an air-to-water heat pump saves 50–70% on heating bills.
Which type of heat pump to choose in Luxembourg?
For most Luxembourg detached homes with gas or oil boilers: air-to-water is the most suitable and best-subsidised. For apartments or homes with direct electric heating: air-to-air is often simpler. For large plots with a high budget: geothermal offers the best performance. See our air-to-water vs air-to-air comparison.
What grants are available for heat pumps in Luxembourg 2026?
Cumulative grants 2026: Klimabonus (up to €9,500 for air-to-water, €14,000 for geothermal) + Enoprimes (~€1,500) + 3% VAT (instead of 17%) + municipal grants. Main condition: minimum COP 3.1 (A7/W35) and approved installer. Simulate your personalised grant on our simulator.
Should you insulate your home before installing a heat pump?
Yes, strongly recommended. In a poorly insulated home (class E/F/G), the real SCOP drops to 2.0–2.5, making the installation much less cost-effective. Golden rule: insulate first, install the heat pump second. See our insulation prerequisite guide.
How long does a heat pump last and what maintenance is required?
A well-maintained heat pump lasts 15 to 20 years. Annual professional servicing is recommended: filter cleaning, refrigerant check, hydraulic pressure check. Cost: €150–€300/year — about 5 times less than a boiler service contract. Heat pump maintenance guide.
Take action — your heat pump quote in August 2026
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