Heat Pump Subsidies in Luxembourg

What the public support covers

Installing a heat pump falls under the Klimabonus Wunnen, with different treatment depending on whether it replaces an existing fossil heating system in an older home or equips a new building. Replacing an oil or gas boiler is generally treated as its own strand, since it specifically targets the phase-out of fossil fuels.

Air-water and geothermal systems (ground-water or water-water) both fall under the same scheme, but each carries its own technical requirements, notably linked to drilling for geothermal systems. The amounts and conditions applicable at the time of your application are published on guichet.lu and should be checked before any commitment.

Air-water or geothermal: two different logics

An air-water heat pump draws heat from outside air; installation is faster and less invasive, but its efficiency varies with outdoor temperature. A geothermal heat pump draws heat from the ground via probes or a horizontal loop, with more stable year-round efficiency, at the cost of more extensive drilling or earthworks and a prior soil survey.

The choice between the two depends on available land, budget and access constraints for drilling, but also on the home's existing structure: a renovation with limited outdoor space often points to air-water, while a new build with available land may justify a geothermal borehole.

The heat load assessment and emitter temperature

A heat load assessment of the home is needed to size the heat pump correctly: an oversized unit costs more upfront and runs in short cycles that shorten its lifespan, while an undersized one fails to cover needs during cold spells. This calculation must be documented by the company, independently of the subsidy application.

The operating temperature of existing heat emitters — radiators or underfloor heating — directly affects the heat pump's efficiency. A system designed for a high-temperature boiler performs poorly with a heat pump without adaptation: replacing some radiators with low-temperature models, or checking that existing underfloor heating is suitable. This adaptation is part of the project and must appear in the quote.

Decommissioning the old system

Replacing an oil or gas boiler involves removing the old equipment, including the oil tank where applicable, whose disposal follows specific rules. This step must be planned and costed in the quote: it often determines eligibility for the fossil-fuel replacement strand, which is distinguished from a simple new installation.

The heat pump's electrical connection must also be checked by an electrician, as the power drawn often exceeds that of conventional electric heating.

Documents, process and common reasons for rejection

The sequence to follow: energy advice from Klima-Agence, a heat load assessment and detailed quote from an authorised heating company, prior approval where the strand requires it, the works and decommissioning of the old system, a detailed invoice, then submitting the file with the heat load assessment, the unit's technical data sheet and proof that the old installation was disposed of.

Frequent rejections involve a file without a documented heat load assessment, confusion between the fossil-fuel replacement strand and the new-build one, or works started before the required prior approval. Communal subsidies, which vary by commune, add to the national scheme: check with your commune's technical department.

Where to find binding figures

The exact amounts, caps and technical conditions, notably the performance threshold required depending on the technology, are published on guichet.lu. Klima-Agence offers free, independent energy advice, particularly useful for deciding between air-water and geothermal before requesting quotes.