Financial aid may be sought by any person wishing to improve the energy performance of their home (single-family house or house divided into flats). Eligible candidates include:

• natural persons;
• legal persons established under private law;
• public legal persons other than the State.

You can submit your application in your capacity as:

• legal representative of a group of natural or legal persons, provided that you are a part of this group yourself;
• owner(s) of the dwelling, except when there is a change of ownership and the new owner of the dwelling and/or technical installation forgoes the aid in question for the benefit of the former owner who made the investments.

Installations and residences

The Klimabonus aid:

• is granted only for residential buildings located in Luxembourg;
• is not be granted for:
  • used (second-hand) systems; or
  • an exchange, replacement or repair of a part of a system that cannot function independently of the rest of the system.

Technical installations for which financial aid was granted under the 2012 or 2017 financial aid scheme are not eligible.

Requirements

Hydraulic balancing

The heating network must undergo hydraulic balancing upon the installation of:

• heat pumps;
• solar thermal systems with complementary heating in a new single-family house or new multi-unit building.

Solar thermal systems

Solar thermal systems must meet the following requirements:

• solar thermal collectors must be certified by the European Solar Keymark quality mark;
• the installation must be equipped with a calorimeter;
• the gross surface area of the collectors with complementary heating must be:
  • greater than or equal to 9 m² for flat-plane collectors;
  • greater than or equal to 7 m² for vacuum tube collectors;

Non-glass thermal collectors with polyethylene pipes and hybrid solar collectors generating hot water and electricity are not eligible for the financial aid.

Solar photovoltaic systems

Solar photovoltaic systems must meet the following requirements:

• the peak power capacity of the installation must be lower than or equal to 30 kW;
• the system must be:
  • installed on the roof or facade of the building; or
  • incorporated in the building envelope.

Hybrid solar collectors generating hot water and electricity are eligible as photovoltaic collectors.

The electricity storage facility can be an eligible element when applying for financial aid for a new photovoltaic installation if the following conditions are met at the same time:

1. the storage facility is connected to a solar photovoltaic installation operated in self-consumption mode or as part of an energy community;
2. the peak power capacity of the solar photovoltaic installation is greater than 4 kW and, in the case of a multi-unit residential building, greater than 1.5 kW per unit;
3. the storage capacity of the storage facility for the energy produced is less than or equal to:
   • 1.5 kWh per kW_peak of the photovoltaic (PV) installation where the solar photovoltaic installation and the storage facility supply a building used for residential purposes, without exceeding:
     • 12 kWh for a single-family home;
     • 9 kWh per unit in a multi-unit residential building.
   • 1 kWh per kW_peak of the photovoltaic (PV) installation where the solar photovoltaic installation and the storage facility supply a building that is not used for residential purposes.

Heat pumps

Heat pumps concerned

The following heat pumps and hybrid heat pumps are concerned:

• geothermal heat pumps with vertical sensors (geothermal probes) or horizontal sensors (geothermal collecting lines and baskets) meeting the following coefficient of performance (COP) requirement: COP is equal to or greater than 4.3 at B0/W35, determined in accordance with the EN 14511 standard;
• hybrid geothermal heat pumps for existing residential buildings that:
  • are installed in addition to an existing heating system to create a hybrid system, or are installed in the form of combined hybrid devices to replace an existing heating system; and
  • must meet the following coefficient of performance (COP) requirement: COP is equal to or greater than 4.3 at B0/W35, determined in accordance with the EN 14511 standard;
• direct expansion geothermal heat pumps meeting the following coefficient of performance (COP) requirement: COP is equal to or greater than 4.3 at E4/W35, determined in accordance with the EN 14511 standard;
• heat pumps combined with a latent heat accumulator and a solar thermal collector, meeting the following coefficient of performance (COP) requirement: COP is equal to or greater than 4.3 at B0/W35, determined in accordance with the EN 14511 standard;
• air-to-water heat pumps (including vented air-to-water heat pumps) meeting the following coefficient of performance (COP) requirement: COP is equal to or greater than 3.1 at A2/W35, determined in accordance with the EN 14511 standard;
• hybrid air-to-water heat pumps for existing residential buildings that:
  • are installed in addition to an existing heating system to create a hybrid system, or are installed in the form of combined hybrid devices to replace an existing heating system; and
  • must meet the following coefficient of performance (COP) requirement: COP is equal to or greater than 3.1 at A2/W35, determined in accordance with the EN 14511 standard.

Requirements to be met

The relevant heat pump must meet the following requirements:

• the heating system must be able to supply the heating circuit with a maximum starting temperature of 35°C (35W). If this is not the case, the coefficient of performance of the heat pump must reach at least the required threshold at W35 with the chosen starting temperature;
• the rated capacity of the heat pump is determined at 100 % output, under the conditions indicated in the previous paragraph;
• the power supply of the heat pump must be equipped with an electricity meter;
• the heat pump for which the invoice was issued from 1 January 2024 must be equipped with a heat meter;
• when a heat pump is installed, the heating network must undergo hydraulic balancing;
• for heat pumps and hybrid heat pumps for existing residential buildings, a buffer tank with a minimum capacity of 30 l/kW _thermal must be installed, with the exception of heat pumps and hybrid heat pumps equipped with a variable frequency drive ('inverter') with speed/power modulation;
• a geothermal heat pump or hybrid air-to-water heat pump must be able to operate on its own, i.e. in monovalent mode, and the hybrid system must cover at least 70 % of the useful heat demand for the year in heat pump mode;
• for air-to-water heat pumps and hybrid air-to-water heat pumps, the sound power LW ('Schallleistungspegel'; based on the EN 12102 standard) for the heat pump component installed on the building exterior must meet the following requirements:

* For a system whose external component exceeds the maximum value shown in the table above, the value to take into account may be reduced by adding a soundproofing and noise protection system that reduces the sound emitted by the heat pump's external component. The sound-reduction value in dB(A) must be guaranteed and specified in the technical data of the soundproofing equipment.

Alternatively, if the sound power requirements L_W in the above table are not met, the noise level, increased where necessary by correction terms, caused at the boundary of the nearest building site to the fixed technical equipment of the heat pump installed outside the building must not exceed 40 dB(A).

In order to demonstrate that the installation complies with this requirement, a noise assessment based on a calculation of noise emissions shall be carried out for the fixed technical components of the heat pump installed outside the building. It is established prior to the installation of the heat pump and exclusively on the basis of a calculation tool called the 'calculatrice des émissions sonores' (noise emission calculator) made available by the Ministry.

For heat pumps without an outdoor unit, installed entirely within the building envelope, the acoustic calculation must be carried out exclusively using the calculation tool provided by the Ministry.

Wood-fuelled boilers

In order to be eligible:

• the installation must have a controlled combustion system (power and combustion regulation);
• wood-pellet or wood-chip boilers must be equipped with an automatic feeder and ignition system;
• wood pellet stoves must be integrated in a central heating system and the degree of useful heat transfer must reach at least 50 %;
• for staged log combustion boilers and combination wood log-pellet boilers, a buffer tank with a minimum capacity of 55 l/kW _{rated thermal capacity} must be installed;
• the following emission and yield thresholds must be complied with:
  • particle emission less than or equal to 8 mg/m³;
  • nitrogen oxide (NO) emission less than or equal to 200 mg/m³;
  • boiler production yield greater than or equal to 90%;
  • combustion yield of pellet stove greater than or equal to 90%.

Wood-fuelled boilers may be equipped with a particulate filter (electrostatic or other) whose separation efficiency ('Abscheidegrad') must be such that the particle emission rate of the system after commissioning/acceptance does not exceed 8 mg/m³.

Heating networks and connections

The rate of coverage by renewable energy sources must be greater than or equal to 75% (substantiated by presenting a certificate issued by the heating network operator).

The transfer of heat between the heating network and the residential building must occur through a heat transfer station.

Invoices

Invoices for the technical installations must be issued between 1 January 2022 and 31 December 2025 inclusive at the latest.

Applications for the financial aid must be filed with the Single point of contact for housing assistance within 4 years as of 31 December of the calendar year in which the invoice was issued.

The financial aid may be requested for the investments and services for which the invoice is issued:

• between 1 January 2022 and 31 December 2025 inclusive;
• for all technical installations, other than photovoltaic systems, until 31 December 2029 inclusive, if the investments are concurrent with the energy efficiency renovation of an existing building.

If the installations:

• are not concurrent with the energy efficiency renovation, the deadline for submitting the application is 31 December 2031 at the latest;
• are concurrent with a new sustainable construction that is eligible under the 2017 aid scheme, the deadline for submitting the application is 31 December 2028 at the latest.

For solar photovoltaic installations operated in self-consumption mode or as part of an energy community, the financial aid allocated is increased by a financial aid bonus of 25 % provided:

• the order is placed between 1 January 2023 and 31 December 2023 inclusive; and
• the invoice is issued by 31 December 2025 at the latest.

The financial aid bonus in addition to the financial aid for the replacement of:

• an existing fossil fuel boiler; or
• existing electrical heating system;
• combined with an improvement of the energy performance of the heating system by installing a heat pump, a hybrid heat pump or a wood-fuelled boiler;

is increased from 30 % to 50 % for any installation ordered between 1 November 2022 and 31 December 2023, on condition that the invoice is issued no later than 31 December 2025.

Submitting the application

Applications must be submitted after the work has been completed:

• either online via MyGuichet.lu or the MyGuichet.lu mobile application (see 'Online services and forms' below). This is a procedure with authentication that requires:
  • a LuxTrust product (Token, Smartcard or Signing Stick); or
  • an electronic identity card (eID);
• or by post (preferably by registered mail), or by handing in the dedicated form (see 'Online services and forms') at the Single point of contact for housing assistance (Guichet unique des aides au logement):
  • if you are a private individual: the DEPA-2022 aid application form for natural persons; or
  • if you represent a legal person: the DEPA-2022 financial aid application form for legal persons.

Supporting documents

In addition to the financial aid application, you must also provide:

• the detailed and receipted invoices in connection with the requested financial aid. The invoices may refer to an itemised estimate, in which case the latter must be attached to the invoice;
• one or more specific technical data sheets, depending on the type of installation:
  • photovoltaic system;
  • heat network or connection to a heat network;
  • solar thermal systems;
  • heat pumps;
  • wood-fuelled boilers;
• if applicable, the energy consultation related to the technical installation(s) concerned;
• if applicable, the dated order form for the photovoltaic installation;
• if applicable, the dated order form for the heat pump or wood-fuelled boiler.

Given that each application may cover different domains depending on the owner's or architect's choices, the various sheets should be accompanied by any additional documents specified on the application forms.

If the application is for a commonhold property or multi-unit residence, you must attach:

• appendix form COLL-2022;
• a power of attorney from each owner;
• the list of the flats, specifying the energy reference area per flat, excluding the common areas.

The Single point of contact for housing assistance may ask you to provide any documents it deems necessary to process the file.

If the aid is granted, the beneficiary's file may be reviewed at any time.

Note: implementing technical installations may also be eligible for financial aid for an energy consultation and a report by an approved energy consultant. If the improvement only applies to a renewable energy-based technical installation, the subsidy will be reduced by 70 %.

Table of subsidies for technical installations

Subsidies for solar thermal systems

An additional flat-rate subsidy of EUR 1,000 may be granted if the solar thermal system is installed concurrently with a wood-fuelled boiler or a heat pump.

Subsidies for solar photovoltaic systems

Subsidies for heat pumps

Subsidies for wood-fuelled boilers (for existing residences only)

Urban heating network

Additional aid and bonus

Heat pumps

A financial aid bonus of 30 % may be granted if:

• the fossil fuel, electric or electric storage heating system was manufactured at least 10 years prior to the year of filing for the financial aid. This bonus is also allocated if, in a hybrid system, a heat pump is combined with an existing fossil fuel boiler and this boiler is removed within 5 years of the date of issue of the invoice;
• the replaced heating system was used as the main source of heating;
• a report evaluating the energy performance of the heating system was drawn up using the 'Heizungscheck' tool (not necessary if an electric heating system is being replaced);
• the upgrades recommended further to the energy performance assessment have been implemented.

The aid bonus is increased from 30 % to 50 % of the financial aid for any installation ordered between 1 November 2022 and 31 December 2023, on condition that the invoice is issued no later than 31 December 2025.

Additional aid for the removal, neutralisation and recycling of the oil tank may be granted if:

• the oil heating system was manufactured at least 10 years prior to the year of filing of the financial aid;
• the replaced heating system was used as the main source of heating;
• an energy performance assessment report for the heating system was established using the 'Heizungscheck' tool;
• the upgrades recommended further to the energy performance assessment have been implemented.

Additional aid for the adaptation of the existing heating distribution system may be granted if an existing boiler is being replaced by a geothermal heat pump or an air-to-water heat pump, and if:

• the fossil fuel heating system was manufactured at least 10 years prior to the year of filing of the financial aid;
• the replaced heating system was used as the main source of heating;
• an energy performance assessment report for the heating system was established using the 'Heizungscheck' tool;
• the upgrades recommended further to the energy performance assessment have been implemented.

Wood-fuelled boilers

Aid for the installation of a particulate filter on an existing boiler may be granted. This financial aid is capped at EUR 1,500 and may not exceed 50 % of the actual costs.

A financial aid bonus:

• of 15 % may be granted if a buffer tank is installed (30 l/kW_{thermal rated capacity});
• of 30 % may be granted if:
  • the fossil fuel, electric or electric storage heating system was manufactured at least 10 years prior to the year of filing for the financial aid;
  • the replaced heating system was used as the main source of heating;
  • a report evaluating the energy performance of the heating system was drawn up using the 'Heizungscheck' tool (not necessary if an electric heating system is being replaced);
  • the upgrades recommended further to the energy performance assessment have been implemented.

The aid bonus is increased from 30 % to 50 % of the financial aid for any installation ordered between 1 November 2022 and 31 December 2023, on condition that the invoice is issued no later than 31 December 2025.

Additional aid for the removal, neutralisation and recycling of the oil tank may be granted if:

• the oil heating system was manufactured at least 10 years prior to the year of filing of the financial aid;
• the replaced heating system was used as the main source of heating;
• an energy performance assessment report for the heating system was established using the 'Heizungscheck' tool;
• the upgrades recommended further to the energy performance assessment have been implemented.

Urban heating network

A financial aid bonus of 30 % may be granted if:

• the fossil fuel, electric or electric storage heating system was manufactured at least 10 years prior to the year of filing for the financial aid;
• the replaced heating system was used as the main source of heating.

Additional aid for the removal, neutralisation and recycling of the oil tank may be granted.

Other aid

Some communes grant additional aid. Applicants may estimate the amount of communal aid they are eligible for by using the Klima-Agence simulator.

Natural gas and electricity suppliers operating in Luxembourg also offer aid programmes for the implementation of energy efficiency measures. The list of suppliers is available on the website of the Luxembourg Regulatory Institute (Institut Luxembourgeois de Régulation - ILR):

• list of electricity suppliers;
• list of natural gas suppliers.

Payment of the aid

The aid is generally transferred directly to your bank account.

If you act in your capacity as a legal representative of a group of natural or legal persons, the aid is transferred directly to your bank account and you must immediately credit the bank accounts of the natural or legal persons concerned with their respective share of the aid.

A copy of these payments must be sent to the Single point of contact for housing assistance.

Repayment of the aid

If you have already received the aid, you may be required to return it, if:

• you are found to have made inaccurate or incomplete statements in order to obtain the aid; or
• you fail to provide the Single point of contact for housing assistance with the requested declaration, information or documents.

Procedures

Links