PEB in Wallonia: understanding your score and going from E to C

The PEB certificate (Energy Performance of Buildings) has been mandatory in Wallonia for any sale or rental since 2010. Since 2024, the requirements have tightened: a home rated F or G can no longer be rented out from 2030, and the renovation obligation applies progressively to landlords. Here is how to navigate the PEB system in 2026.

Understanding the PEB score

The PEB rates homes from A++ (very efficient) to G (very energy-hungry), based on primary energy consumption in kWh/m².year:

Class	Consumption (kWh/m².year)	Description
A++	< 0	Energy-producing building
A+	0 to 45	Passive building
A	45 to 85	Very low energy
B	85 to 170	Low energy
C	170 to 255	Good performance
D	255 to 340	Average performance
E	340 to 425	Low performance
F	425 to 510	Very low performance
G	> 510	Energy-hungry

The average Walloon home is rated E (370 kWh/m².year). The political objective is to bring the entire residential stock below the 255 kWh/m².year threshold (class C or better) by 2050.

The PEB in 2026: what has changed

Since January 1, 2026, several novelties impact owners:

1. Validity period: 10 years for certificates issued after 2024 (versus 10 years with a recommended review at 5 years previously).
2. Mandatory home audit for any property rated E, F or G put up for sale. The audit identifies priority works and their order.
3. Habitation grant bonus of 25% if you follow the works order recommended by the audit.
4. Rental ban progressive: G in 2028, F in 2030, E in 2035.

Reading your PEB report

A standard PEB certificate runs 8 to 12 pages. The sections to understand:

Page 1: class and figures

This is the visual summary. You will find your class (A to G), your primary consumption and your CO₂ emission. Important note: primary consumption differs from your actual bill. The PEB is a standardised theoretical calculation, your real consumption also depends on your behaviour.

Pages 3 to 6: breakdown

The certifier breaks down heat losses per wall:

• Roof: if uninsulated, almost always the priority area.
• Walls: external wall insulation (EWI) is the most effective but also the most expensive.
• Floors and slabs: often overlooked, can represent 10 to 15% of losses.
• Frames and glazing: standard double glazing since 1995, triple glazing since 2015.
• Heating system: boiler type, efficiency, age.
• Ventilation: presence or absence of mechanical ventilation.

Page 7 onwards: recommendations

The certifier lists priority works with estimated savings. This is your roadmap.

From E to C: the optimal path

For a Walloon home rated E (370 kWh/m².year), here is the works sequence that maximises energy gain and grants:

Step 1: roof insulation (gain 25 to 35%)

This is always where to start. Average cost €2,000 to €3,500 for a 100 m² home (before grants). Wallonia Habitation grant: €30 to €50/m² depending on income. Bill savings: €350 to €600/year.

See our comparison glass wool vs PIR vs cellulose.

Step 2: double or triple-glazed frames (gain 8 to 12%)

If your frames are single-glazed or pre-2000 double-glazed, replacement brings 8 to 12% gain. Average cost €600 to €1,200/frame installed. Wallonia grant: €60/m² of glazing for double, €120/m² for triple.

Step 3: heating system (gain 15 to 25%)

Replacing a pre-2010 oil boiler with an air-water heat pump or a gas condensing boiler. Cost €8,000 to €18,000 depending on the technology. Heat pump grant: up to €4,500 in Wallonia in 2026.

Step 4: wall insulation (gain 15 to 20%)

EWI (external thermal wall insulation) is the best but costs €100 to €150/m². Internal insulation is cheaper (€40 to €80/m²) but reduces living space and shifts the thermal bridge.

Step 5: mechanical ventilation (gain 5 to 10%)

Without mechanical ventilation, your insulated home becomes a humidity pressure cooker. Dual-flow ventilation recovers 70 to 85% of the heat from extracted air. Cost €4,500 to €8,000 installed.

Typical result

A 100 m² Walloon home rated E that follows this path lands at C or C+ after €25,000 to €40,000 invested (before grants), recovered in 12 to 16 years via energy savings. Bonus: your property gains 8 to 15% in real-estate value.

Choosing a PEB certifier

The PEB certificate can only be issued by a certifier accredited by Wallonia. There are about 1,800 active in 2026.

Criteria to choose:

• Accreditation number: to be checked on the official Walloon Region website.
• Price: between €200 and €350 for a standard home. Beware of offers below €180 (often rushed in 30 minutes).
• Lead time: a serious certifier spends 1h30 to 2h on site, then 3 to 5 days to produce the report.

On Batizzy, you find verified Wallonia PEB certifiers with customer reviews. Find a PEB certifier.

Common mistakes

1. Doing the audit after the works

The audit must be done BEFORE to scope the project and unlock the 25% bonus. Too many owners launch the works and then ask for the audit, losing the bonus.

2. Forgetting the mention on the listing

For rental or sale, the PEB score must appear on every real-estate listing. A listing with no PEB mention can lead to an administrative fine of up to €1,000.

3. Confusing PEB with an insulation study

The detailed insulation study (carried out by a thermal engineering office) is more thorough than the PEB. It costs €800 to €1,500 but gives an ultra-precise roadmap. If you plan works above €30,000, the investment pays off.

How Batizzy helps you

On Batizzy, you can:

• Find an accredited PEB certifier near you
• Get comparable quotes for insulation, frames, heating works
• Track every job's progress in a unified interface
• Keep a history of invoices (useful for grants and resale)

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