Residential Energy Audit in Wallonia: Is It Compulsory to Qualify for Grants?

The residential energy audit has become an essential step for many Walloon homeowners looking to renovate their property. But is it automatically required to access renovation grants? The answer depends on the type of works involved and the scheme you wish to apply for. Here is a clear overview of the situation as it stands in 2026.

What is a residential energy audit?

A residential energy audit is an in-depth assessment of your home carried out by an auditor accredited by the Walloon Region. The auditor inspects the insulation, heating system, ventilation and airtightness of your property. The result is a detailed report that sets out a personalised renovation pathway, with costed priorities.

This report is not simply an opinion. It is an official document, recorded in the Walloon Region's database, which serves as the basis for certain grant applications. The on-site audit typically takes between two and four hours, depending on the size of the property.

In 2026, the cost of a residential energy audit ranges from €700 to €1,200 for a single-family home, before any available subsidies are deducted. A dedicated grant covers part of this cost, which significantly reduces the bill for the homeowner.

Which grants require an audit?

In Wallonia, the residential energy renovation grant system has for several years been built around two main schemes: the Habitation grants (formerly the Energy grants) and the zero-interest loan mechanism. Since the 2023 reform - confirmed and adjusted in 2025 - an energy audit is compulsory in the following situations:

• Whole-house renovation: if you want to carry out several works in a single process and benefit from the higher grant rate, a prior audit is required. The renovation pathway produced by the audit determines the order in which the works should be carried out.
• Zero-interest loan (Rénopack or Écopack depending on the operator): to access this type of advantageous financing through the Fonds du Logement or certain municipalities, an audit is often required as supporting documentation.
• Works on highly energy-inefficient properties (EPC rating F or G): since 2025, certain works on properties rated F or G require a prior audit in order to benefit from the highest grant rates.

For standalone, one-off works - such as replacing a boiler or installing solar panels - an audit is generally not required. An invoice from an accredited installer and a few administrative documents are sufficient in these cases.

When is an audit not compulsory?

Several types of works remain accessible without a prior audit. This is the case in particular for:

• Roof or loft insulation carried out by an accredited contractor
• Installation of a heat pump to replace an oil-fired boiler
• Installation of high-performance double glazing
• Installation of photovoltaic panels

For these specific works, you can submit your grant application directly through the Walloon Region's online portal, without going through an accredited auditor. This simplifies the process and reduces processing times.

That said, even where an audit is not compulsory, it can still be worthwhile. An auditor may identify problems you had not anticipated and help you avoid costly mistakes when choosing what works to carry out. Some homeowners who intended to replace their boiler as a first priority discovered, after an audit, that insulation was the intervention to tackle first for better overall performance.

How much does the audit cost and how is it subsidised?

The Walloon Region directly subsidises the residential energy audit. In 2026, the audit grant covers 70% of the cost for low- and middle-income households, with a ceiling set at €900. For higher-income households, the grant is 30% with a ceiling of €450.

These amounts may vary depending on your municipality if it has put in place an additional subsidy. Some Walloon municipalities, as part of their energy-climate action plans, offer supplementary grants to encourage audits on their territory.

The grant application for the audit is submitted after the audit has been completed, via the Walloon Region's online portal. You have six months from the date of the report to submit your application.

Energy audit and resale value: a direct link

Beyond grants, the energy audit plays an increasingly important role in the market value of a property. In Wallonia, buyers now pay close attention to the EPC certificate, but also to the renovation potential of a home. A property accompanied by a recent audit report, with a clearly defined renovation pathway, inspires confidence and can make negotiations easier.

If you are considering selling your property in the coming years, having an audit carried out now can therefore serve two purposes: accessing grants to improve your home and increasing its value on the market. Properties with a good energy performance rating sell on average 8 to 12% more than comparable properties with a poor EPC, according to Walloon market data for 2026.

Before putting your property on the market, it may also be worth getting a free valuation of your property to measure the real impact of the works on your asking price.

How to find an accredited auditor in Wallonia

Only auditors recognised by the Walloon Region can carry out an audit that qualifies for grants. The list of accredited auditors is available on the Region's energy portal. You can filter by province or by postcode.

Before choosing an auditor, it is advisable to request at least two quotes. Rates vary considerably from one provider to another, and the quality of the report can differ as well. A good auditor takes the time to explain their findings and helps you understand the proposed renovation pathway.

If you are a homeowner considering selling your property after renovation, comparing local estate agents can help you identify the right moment to put your home on the market and maximise your return on investment.

FAQ

Is an energy audit compulsory for all grants in Wallonia?

No. An audit is compulsory for whole-house renovations and certain zero-interest loans, but not for standalone works such as replacing a boiler or installing solar panels. In those cases, an invoice from an accredited contractor is sufficient.

How long is an audit report valid?

In Wallonia, a residential energy audit report is valid for ten years. This gives you time to spread your works over several years while retaining the right to the grants linked to the renovation pathway set out in the report.

Can I apply for the audit grant before starting the works?

No. The audit grant application is submitted after the audit has been completed. You have six months from the date of the report to submit your application via the Walloon Region's online portal.

Can an energy audit influence the sale price of my property?

Yes. A property with a good EPC rating or a clearly documented renovation pathway attracts more buyers. In Wallonia, energy-inefficient properties are subject to a growing discount on the market. Carrying out works following an audit can improve your position when it comes to selling. To find out more, compare estate agents for free in your area.

In summary, a residential energy audit is not automatically compulsory to qualify for grants in Wallonia, but it becomes essential as soon as you are aiming for a whole-house renovation or preferential-rate financing. It is also a worthwhile investment for any homeowner who wants to sell their property under the best possible conditions. Take the time to inform yourself before starting your works, and do not hesitate to seek several professional opinions.