Up to €17,500 in grants
Heat pumps in Luxembourg: is one right for your home?
In Luxembourg, a heat pump is the right choice if the house stays comfortable in very cold weather with heating water at 55 °C or less: it then delivers 3 to 4.5 kWh of heat per kWh of electricity. One of the cheapest heating systems to run, it is also the most subsidised: a €12,000 Klimabonus for an air-to-water unit ordered before 30 June 2027 that replaces fossil-fuel or direct electric heating.
Your result in 2 minutesFree simulator Recommended outputkWEstimated grants€Savings€ Instant result, no obligationStart the simulation →- Efficiency: 1 kWh of electricity gives 3 to 4.5 kWh of heat over the year (SCOP), depending on the emitters and the heat source
- Key condition: a house that stays comfortable with heating water at no more than 55 °C in a cold spell, ideally 35 to 45 °C
- Subsidised types: air-to-water and ground source. An air-to-air heat pump (reversible air conditioning) gets no Klimabonus
- Installed price: air-to-water €12,000 to €24,000, ground source €25,000 to €45,000 (3% VAT)
- Klimabonus 2026 (house, replacing fossil or electric heating): €12,000 for air-to-water, €14,000 for ground source when ordered by 30 June 2027
- After installation: acceptance by the Chambre des Métiers requested within a month, first inspection 1 to 2 years after commissioning, then every 4 years
How does a heat pump work?
A heat pump does not make heat: it takes it from the outdoor air or the ground, then raises its temperature with an electric compressor, like a fridge working in reverse. A refrigerant circulates in a closed loop through four stages.
Evaporation
The very cold refrigerant absorbs heat from the air or the ground and turns to vapour, even when it is freezing outside.
Compression
The electric compressor squeezes this gas and its temperature rises sharply. This is the only stage that uses electricity.
Condensation
The hot gas gives up its heat to the water in the radiators, the underfloor heating or the hot-water cylinder, and turns back into liquid.
Expansion
The expansion valve drops the pressure and temperature of the liquid, which goes back to pick up heat. The cycle starts again.
Because the heat drawn from outside is free, a heat pump returns on average 3 to 4.5 kWh of heat per kWh of electricity over the year. The cooler the water it has to produce, the better this ratio: that is why underfloor heating, which needs only 35 °C, is the ideal emitter. On refrigerants, Regulation (EU) 2024/573 bans, from 1 January 2027, placing on the market new air-to-water heat pumps of 12 kW or less whose refrigerant has a GWP of 150 or more, such as R32: propane (R290) is becoming the standard.
Air-to-water, ground source, air-to-air, hybrid: which heat pump for which house?
In Luxembourg, the air-to-water heat pump suits the vast majority of houses with wet central heating; ground source is for long-term projects with land, and air-to-air for homes without central heating.
| Type | Source and distribution | Suited to | Klimabonus 2026 (house) |
|---|---|---|---|
| Air-to-water | Outdoor air → water for radiators or underfloor heating, domestic hot water | Replacing an oil or gas boiler in a house: the typical case | €12,000 (ordered by 30/06/2027), then €10,000 |
| Ground source | Ground, via drilled vertical boreholes or horizontal collectors → water | Accessible plot, drilling permitted, underfloor heating, horizon of 20 years or more | €14,000 (ordered by 30/06/2027), then €12,000 |
| Compact ventilation + heat pump | Exhaust air from the ventilation system → water | Very high-performance house with heat-recovery ventilation | Same as air-to-water |
| Hybrid | Heat pump + back-up boiler | Transition in a house not yet insulated | Only if the back-up is not fossil and the heat pump covers at least 70% of demand |
| Air-to-air | Outdoor air → air blown into the rooms | Flats, rooms without central heating | None |
Installed prices by type and output: see how much a heat pump costs in Luxembourg.
Air-to-air or air-to-water heat pump: which to choose in Luxembourg?
If your house has wet central heating, choose air-to-water: it is the only one of the two that replaces the boiler, produces hot water and qualifies for the Klimabonus. Air-to-air, a reversible air-conditioning system, heats and cools room by room, with no grant and normally at 17% VAT.
To cool a flat or a few rooms, the right starting point is our guide to air conditioning in Luxembourg, which compares reversible air conditioning (air-to-air) or air-to-water heat pump in detail.
COP and SCOP: what efficiency to expect from a heat pump in Luxembourg?
COP measures a heat pump’s instantaneous efficiency in the lab, SCOP its average efficiency over the whole heating season: SCOP is what drives your bill. A SCOP of 3.5 means a house needing 18,000 kWh of heat uses about 5,150 kWh of electricity a year.
COP is measured under standard EN 14511 at a fixed point, for example A7/W35 (air at 7 °C, water at 35 °C). It is the figure the Klimabonus checks: at least 3.1 at A7/W35 for air-to-water and 4.3 at B0/W35 for ground source. SCOP (standard EN 14825) depends mainly on the temperature of the water sent to the emitters.
| Emitters | Flow temperature in a cold spell | Typical SCOP, air-to-water |
|---|---|---|
| Underfloor heating | 30 – 40 °C | 3.5 – 4.0 |
| Low-temperature or generously sized radiators | 45 – 55 °C | 3.0 – 3.5 |
| Original high-temperature radiators | 60 – 80 °C | 2.5 – 3.0 |
A ground-source unit reaches a SCOP of 4.0 to 4.5 because the ground stays at a stable temperature all year round. Consumption in kWh by floor area depends on this SCOP and on the house’s heat demand.
Is your house ready for a heat pump? Insulation and emitters
A house is ready for a heat pump if it stays comfortable in a cold spell with heating water at 55 °C at most. Insulation and radiator size decide this, not the age of the house.
The simple test: during a cold week, lower your boiler’s flow temperature to 50-55 °C. If every room stays warm, an air-to-water heat pump will work well on your current radiators. If one or two rooms fall short, replacing those radiators is often enough. If the whole house is cold, insulate first.
| State of the house | What to do |
|---|---|
| Insulation class A to C, or underfloor heating | Install the heat pump straight away |
| Class D or E, adequate radiators | Heat pump possible: insulating the roof and replacing undersized radiators clearly improves the SCOP |
| Class F to I, high-temperature radiators | Insulate the roof and walls first, or plan a transition solution |
The heat pump Klimabonus requires no prior insulation, but a heat pump fitted in a house that leaks heat costs more (more output) and uses more. Insulating the roof before sizing the heat pump reduces both. An approved energy advisor sets the order of the works: their report is mandatory as soon as the subsidised renovation covers more than one element.
The limits of a heat pump: cold, noise, space and co-ownership
An air-to-water heat pump still heats at −15 °C, but its efficiency falls with the cold, its outdoor unit must respect noise limits and it needs space outside. These four points should be checked before signing.
- Cold spells: around −7 °C, the COP of an air-to-water unit on radiators drops to about 2 to 2.5 and a back-up heater may take over for a few hours. Spells below −10 °C are rare in Luxembourg: the effect on the annual bill is limited if the heat pump is correctly sized. Ground source is barely affected.
- Noise: for the Klimabonus, the sound power of the outdoor unit must not exceed 48, 51 or 55 dB(A) depending on output (up to 5 kW, 5 to 12 kW, above), or the noise at the boundary of the neighbouring buildable plot must stay below 40 dB(A), checked with the official calculator schallrechner.lu. Sound power model by model: see our heat pump brand comparison.
- Space and permits: the municipality decides. The model building regulation proposed to municipalities sets a minimum 2 m set-back from the boundary for an air-to-water outdoor unit. Check before ordering: details in heat pump regulations in Luxembourg.
- Co-ownership: a unit on the façade or in common areas must be authorised by the general meeting by a majority of the votes of all co-owners. See heat pumps in flats.
What heat pump output does your house need?
The right output is the one that covers the house’s heat loss at your municipality’s design outdoor temperature, about −10 °C in the centre and south of the country and −12 °C in the Oesling. It is calculated room by room under standard EN 12831.
Never copy the output of the old boiler, which is often two to three times too high. An oversized heat pump costs more and runs in short cycles; an undersized one leans on its electric heater. In practice, a recent 150 m² house needs 5 to 8 kW, a house from the 1980s or 1990s 8 to 12 kW. The calculation method is set out in sizing a heat pump.
Heat pumps and domestic hot water
An air-to-water heat pump also produces domestic hot water, with a 200 to 300-litre cylinder for a family of four. As hot water is produced hotter than heating water, efficiency is lower, around 2.5 to 3, which means about 1,500 to 1,800 kWh of electricity a year for four people.
Three set-ups exist: a cylinder built into the indoor module, a separate cylinder connected to the heat pump, or a stand-alone heat pump water heater, useful if the boiler stays or if the heat pump is air-to-air. A solar water heater can complement the heat pump: the Klimabonus supports a solar hot-water system with €2,500. Manufacturers usually programme an anti-legionella cycle that takes the cylinder to around 60 °C once a week.
Prices and grants in brief
An air-to-water heat pump costs €12,000 to €24,000 installed, a ground-source system €25,000 to €45,000, before a Klimabonus of €12,000 or €14,000 (house, replacing fossil-fuel or direct electric heating) for orders placed by 30 June 2027. The details are in heat pump prices, item by item, grants and their conditions and the simulator for your own case.
Does a heat pump pay off in Luxembourg?
Yes, in a reasonably insulated house replacing an oil or gas boiler: after the €12,000 Klimabonus, the extra cost is recovered in 5 to 15 years through energy savings of about €650 to €800 a year. And if the boiler had to be replaced anyway, the heat pump is often cheaper from day one.
| Case (ordered before 30/06/2027) | Net cost | Energy saving per year | Payback |
|---|---|---|---|
| 2005 house, 140 m², gas → 8 kW air-to-water | ≈ €3,970 | ≈ €800 | ≈ 5 years; cheaper than a new gas boiler (€7,000 to €11,000) |
| 1975 house, 150 m², oil → 12 kW air-to-water + 4 radiators | ≈ €9,040 | ≈ €650 | ≈ 14 years; cheaper than a new oil boiler (€10,000 to €16,000) |
Three factors drive payback. The SCOP, which depends on insulation and emitters. The ratio between electricity and gas prices: the heat pump wins as long as a kWh of electricity costs less than its SCOP times a kWh of gas, i.e. 3.3 times for a SCOP of 3.3. And solar self-consumption, which lowers the price of the kWh the heat pump uses. The detailed calculations behind these examples are on the price page.
The steps of a heat pump project in Luxembourg
For a heat pump alone, there is no approval in principle to request and no mandatory energy advice: the Klimabonus is claimed after installation. The project follows six steps.
Estimate and get informed
Online simulator, then free advice from Klima-Agence (8002 11 90) if you are unsure about the type of heat pump or the order of the works.
Site visit and quotes
Each installer calculates the heat loss and proposes a model, output, cylinder and ancillary work. Compare at least three offers.
Dated order
The order date decides the increase: order by 30 June 2027 and invoice by 31 December 2028 at the latest to get €2,000 more.
Permits
Municipality for the outdoor unit, general meeting in a co-ownership, drilling permit for ground source. For 3% VAT, the installer requests AED approval before the works.
Installation and commissioning
Two to four days on site for air-to-water, plus drilling for ground source. The installer requests acceptance of the heat pump by the Chambre des Métiers within the following month.
Klimabonus application
On MyGuichet.lu or at the Guichet unique des aides au logement, with form DEPA-2026, sheet POCH-2026 and the invoices, no later than 4 years after the end of the invoice year.
To receive comparable offers, see how to get three heat pump quotes.
Servicing, inspection and lifespan of a heat pump
Under the law of 17 August 2026, published in the Official Journal on 14 September 2026, a water-based heat pump must be inspected like a boiler: first 1 to 2 years after commissioning, then every 4 years, or every 5 years if it is remotely monitored. Forgetting exposes you to an administrative fine of €75 to €5,000.
The inspection is carried out by an inspector trained by the Chambre des Métiers; it does not apply to air-to-air units without a water circuit. Annual servicing is still recommended (€150 to €300 a year) to keep the efficiency and the warranty. An air-to-water heat pump usually lasts 15 to 20 years, the unit of a ground-source system 20 to 25 years. Details in heat pump maintenance.
Take the next step
First estimate the price and grants for your house with the simulator, in 2 minutes. If the project stands up, request 3 quotes from installers established in Luxembourg: site visit and heat-loss calculation included, free and without obligation. For servicing or repairing your current heating, find a verified heating engineer among the trades covered.
From idea to quote
An instant simulation, then offers from installers who know the Klimabonus requirements.
Frequently asked questions about heat pumps in Luxembourg
How do I know whether my house is ready for a heat pump?
Lower your boiler’s flow temperature to 50-55 °C for a cold week. If every room stays comfortable, an air-to-water heat pump will work well with your radiators. If only one or two rooms are cold, replacing their radiators is often enough. If the whole house is cold, insulate the roof and walls first. A house with underfloor heating or rated A to C is ready straight away.
What is the difference between COP and SCOP, and what value should I aim for in Luxembourg?
COP is the efficiency measured in the lab at a fixed point, for example air at 7 °C and water at 35 °C; SCOP is the average efficiency over the whole heating season. The Klimabonus requires a COP of at least 3.1 at A7/W35 for air-to-water and 4.3 at B0/W35 for ground source. For real-world SCOP, aim for 3 or more on radiators and 3.5 or more on underfloor heating.
Air-to-water or ground-source heat pump: which to choose in Luxembourg?
Air-to-water suits most houses: €12,000 to €24,000 installed, fitted in a few days, €12,000 Klimabonus before 30 June 2027. Ground source costs €25,000 to €45,000 but uses about 20 to 25% less electricity, makes no noise outside and receives €14,000. It makes sense with an accessible plot, a permitted borehole and a horizon of 20 years or more.
How much space does an air-to-water heat pump need?
Outside, a clear spot for a unit about one metre wide, on a base or wall-mounted, at least 2 m from the boundary if your municipality applies the model regulation. Inside, the space of a fridge for a module with a built-in cylinder, or a wall-hung module plus a 200 to 300-litre cylinder. The boiler room freed up by the boiler and the oil tank is usually enough.
Does a heat pump improve the energy performance certificate rating?
Yes for two of the three indicators of the energy performance certificate: energy performance, calculated in primary energy, and environmental performance, calculated in CO₂, both of which fall sharply when a heat pump replaces an oil or gas boiler. The thermal insulation class does not move, because it depends only on the building envelope. The exact gain is measured with a certificate issued before and after the works.
Does a heat pump have to be inspected like a boiler?
Yes, under the law of 17 August 2026 (published on 14 September 2026) for water-based heat pumps. The installer requests acceptance by the Chambre des Métiers within a month of commissioning, then a first inspection takes place 1 to 2 years later, and every 4 years after that, or every 5 years if the installation is remotely monitored. Failing to do so carries a fine of €75 to €5,000. Air-to-air units without a water circuit are not covered.