Energy renovation in Liège

Materials, quality, compatibility

A solid result comes from a compatible system from support to finish. We prioritize:

• Suitable insulators (mineral/wood wool, PIR/PUR, cellulose, EPS/XPS) according to use, thickness, summer comfort.
• Breathable plasters/coatings with ETICS, siloxane/silicate finishes according to masonry.
• Frames and fittings from professional ranges distributed in Belgium; glazing with suitable Ug.
• Low-temperature regulations, high-efficiency circulators, balancing.
• Local suppliers and after-sales service (materials and equipment) for reliability and spare parts.

Common problems encountered in Liège

Recurring issues are known; we address them at the source, without "quick fixes".

• Overheating in attics: continuous roof insulation + external solar protection on roof frames.
• Condensation & mold: continuity of the air barrier, improvement of ventilation, and correction of thermal bridges.
• Drafts and high bills: sealing of frame/wall junctions, adjustment of VMC flows.
• Road noise: acoustic glazing + properly installed joinery.
• Oversized boiler: resizing after insulation + balancing and regulation.

The advantages of Avenir Rénovations

You benefit from a project manager who coordinates everything, experienced local teams, and a clean site.

• Clear prioritization: envelope → ventilation → systems, to maximize gain.
• Itemized quotes with readable options; realistic phased schedule.
• Measurable quality: checklists, implementation photos, blower door possible.
• Multi-trade coordination: insulation, frames, roofing, electrician, HVAC.
• Local after-sales service: adjustments, balancing, maintenance, and follow-up.

Urban planning and co-ownership procedures

The majority of interior insulation work does not require permission. On the facade, a change in appearance (rendering ETICS, color, visible thickness, modified frames) may require a Prior Urban Planning Declaration (DUP) or a Urban Planning Permit (PU).

In co-ownership, facade, roofing, and technical ducts are common areas: we prepare a clear file for the property manager/AG (description, colors, schedule, access) and organize signage if it encroaches on the sidewalk. For photovoltaics, the rules are often relaxed, but a simple declaration may still be necessary depending on the municipality and zone.

Grants and access to grants (Wallonia – 2025-2026)

The Walloon Region grants Housing Grants under a temporary scheme in effect until 30/09/2026. In most cases, a Housing Audit by a certified auditor is required to activate the recommended grants from this report (insulation, frames, ventilation, heating).

• Amounts are adjusted according to your income category (R1 → R5) via a multiplier applied to a base amount.
• Exceptions: certain roof items and roof insulation can be incurred without prior audit, but the audit is still recommended to maximize assistance and structure the trajectory.
• We help you compile the file: detailed quotes, before/during/after photos, technical sheets, and plan the related work when the auditor links them to the same wall (e.g. health + insulation).
• Zero-interest loans (Rénopack/Rénoprêt) are available to finance the balance.

Good to know: for a dwelling over 10 years old occupied privately, the 6% VAT may apply under certain conditions.

FAQ

Where to start: insulation or heating?

In the vast majority of cases, we start with the envelope (roof, walls, floors, frames, air tightness). Once the needs are reduced, we size the heating down (better comfort, long-term savings) and adjust the ventilation.

Interior insulation or insulating facade (ETICS)?

The interior is quick, modular "room by room" and interesting in apartments. The ETICS offers uniform performance, eliminates many thermal bridges and refurbishes the facade, but may require an urban planning process. We compare the two according to your street, your frames, and your schedule.

Are hollow walls always injectable?

No. It is necessary to check the presence and width of the cavity, the condition of the joints, and the absence of moisture. When possible, injection offers an excellent cost/benefit ratio with very little disruption.

Is a mechanical ventilation system needed after sealing?

Yes, because a more airtight envelope must be ventilated properly. A well-adjusted extraction (or a double flow mechanical ventilation in some cases) maintains healthy air, protects materials, and improves comfort.

Is a heat pump always the best solution?

Not necessarily. The relevance depends on insulation, emitters, and your consumption profile. Sometimes, a well-sized condensing boiler, balancing, and quality regulation provide excellent results. We advise you transparently.

Can you live in the house during the work?

Most often, yes. The interventions are phased (attics, basement ceilings, linings, frames) to limit dust and noise. For the ETICS, we organize access, protections, and signage.

Need a specialist in energy renovation in Liège?

Benefit from a clear study, a detailed quote with readable options, and a careful execution by local teams.

Contact Avenir Rénovations Liège to build a coherent trajectory, improve your PEB, and stabilize your consumption in the long term.