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When a certificate is required
According to Guichet.lu, an energy performance certificate is required for residential buildings:
- when a new building is constructed;
- when an existing building is extended;
- when an existing building or apartment changes owner or tenant, if there is no valid certificate.
Exceptions exist, for example sales for demolition. A certificate is valid for ten years.
It must be established by a qualified professional: an architect, a consulting engineer, or an expert approved by the ministry. The owner pays for it.
Listings must show the class
Advertisements for the sale or rental of a home must display the energy performance class and the thermal insulation class shown on the valid certificate. If a listing does not show them, ask. A seller or landlord who cannot provide a certificate is not meeting a legal obligation.
How to read the certificate
Luxembourg rates homes on a scale from A+, the best, to I, the worst. The certificate shows several indicators, the most important being:
- Energy performance class: overall primary energy need of the building.
- Thermal insulation class: how well the envelope, walls, roof, windows and floor, keeps heat in.
- Environmental performance: CO₂ emissions linked to the energy used.
The two classes do not always match. A building with modest insulation but a very efficient heat pump can have a better energy class than its insulation class suggests. The insulation class is the better guide to comfort: draughts, cold walls and condensation.
What it means for tenants
For a tenant, the energy class is mostly a question of bills and comfort.
- In buildings with central heating, heating costs are part of the monthly charges and are reconciled once a year. A poor class often means a large balance after a cold winter. See our guide to rental charges.
- In homes with individual heating, you pay the gas or electricity directly, and the difference shows up in your own bills.
- Poorly insulated homes are more prone to condensation and mould, which also matter at the end of the lease.
When comparing two rentals at a similar price, the one with the better class is often the cheaper one to live in. Our viewing checklist includes the questions to ask.
What it means for buyers
For a buyer, the stakes are larger.
Future works
A class F, G, H or I home will almost certainly need energy renovation within the period you own it: insulation, windows, heating. That is a cost to budget, partly offset by national renovation grants and the 3% VAT on renovation work described in our guide to the 3% housing VAT.
Co-ownership costs
Since August 2023, the minimum annual contribution to a co-ownership's works fund depends on the building's energy class: €3 per m² for classes A+ to C, €5 for D and E, and €6 for F to H or where there is no valid certificate. A poor class therefore means higher mandatory contributions. Our guide to buying in a co-ownership explains the fund.
Value and financing
Energy performance increasingly affects how buyers, and banks, see a property. A poor class is often reflected in the price, and some lenders look at it when assessing a loan. Our mortgage guide covers what banks look at.
Rent
For a landlord, a better energy class generally makes a home easier to let, because tenants increasingly compare total monthly cost, not just rent.
Check the date. A certificate issued nine years ago may not reflect works done since, or may predate changes to the calculation method. If you are buying, ask whether any renovation has been carried out since the certificate was issued.
Questions to ask
- What are the energy class and insulation class, and when was the certificate issued?
- What type of heating does the home or building use, and how old is it?
- Have windows, the roof or the facade been renovated? When?
- For an apartment: are any energy works planned or voted by the co-ownership?
- For a rental: what were the actual heating costs last year?
Reading two certificates side by side
Suppose you are choosing between two apartments of 75 m² in the same quarter. The first is in a 1970s building, class F for energy and G for insulation, with an old gas boiler for the building. The second is in a building completed a few years ago, class A for energy and A for insulation, with a heat pump.
Before you look at the price, the certificates already tell you that the first flat will cost more to heat each winter, will have a higher minimum works fund contribution, is likely to face a facade or window renovation in the coming years, and may be colder and more prone to condensation. The second will cost less to run and has most of its major works ahead of it only in the distant future.
That does not make the first flat a bad purchase. It means its price should reflect those costs, and your budget should include them.
Improving a home's class
For owners, the most effective improvements are usually, in order: insulating the roof, replacing old windows, insulating the facade, and replacing an old boiler with a more efficient system. In a co-ownership, most of these are decisions for the general assembly, not for an individual owner, which is why the works fund matters.
National programmes offer grants for energy renovation and for advice before starting works. Get independent energy advice before committing to a large project; the order in which works are done matters for the result.
Our take
The energy certificate is the most underrated document in a Luxembourg property file. For a tenant, it predicts winter bills. For a buyer, it predicts works, co-ownership contributions and, increasingly, resale value. Ask for it at the first contact, not after the offer.
See our homes for rent and properties for sale, or our guide to the buying process.
Sources
This article describes general rules and market practice in Luxembourg and is not legal, tax or financial advice. Rules and announced measures change; confirm the position that applies to you with a notary, your bank or a tax adviser before signing.
