A RE2020-compliant mechanical ventilation and heat recovery assessment for your property — covering airflow schedule, duct specification, unit selection, and full NF DTU 68.3 compliance check. Produces the complete technical dossier required for your MaPrimeRénov' grant application.
VMC double flux — the French regulatory term for MVHR — is a whole-dwelling mechanical ventilation system that recovers heat from extracted air before expelling it outside. Unlike a simple extractor fan, it simultaneously supplies fresh filtered air to habitable rooms and extracts stale air from wet rooms, recovering 80–90% of the heat in the extracted air stream in the process.
In an older stone farmhouse with oil or electric heating, a correctly specified MVHR system reduces heating demand by 15–25% and eliminates the condensation and mould risk that results from upgrading insulation without upgrading ventilation. For any property heading towards airtight performance — whether through new windows, wall insulation, or roof works — MVHR transitions from an optional upgrade to a practical necessity.
The MVHR Sizing Audit determines the correct system for your specific property: room-by-room airflow calculations, duct route planning, unit selection from available French-market models, and a full compliance check against NF DTU 68.3 and RE2020. The resulting report is what your RGE-certified installer quotes from and what Anah requires for a MaPrimeRénov' application.
Stone construction holds moisture. When you improve insulation and airtightness without providing controlled ventilation, that moisture has nowhere to go. The result — within two to three heating seasons — is condensation on cold surfaces, surface mould, and declining indoor air quality. MVHR removes this risk while simultaneously reducing heating costs.
VMC double flux is a separately eligible action under MaPrimeRénov'. From January 2026 it must be coupled with at least one insulation measure to qualify under the par geste pathway. The MVHR Sizing Audit produces the dossier — airflow schedule, compliance check, unit specification — that Anah requires before approving the grant.
Most MVHR audits are completed from floor plans and photographs. An on-site visit is available for Dordogne-area clients and recommended for older properties where duct routing constraints or structural features need to be assessed directly.
The MVHR Sizing Audit produces a single written report containing all the technical documentation required to proceed — whether that is supporting a MaPrimeRénov' application, briefing an RGE installer, or simply deciding whether the system is right for your property.
The Energy Independent · Dordogne · RE2020
Independent · Fee-paid · No installer affiliation
The audit follows a defined workflow. Each step produces a specific output. Nothing is open-ended.
Short no-charge conversation to understand your property, renovation scope, and grant timeline. No commitment required.
Floor plans, room schedule, construction type, existing ventilation, and planning status. Questionnaire or document upload.
Room-by-room airflow calculation per RE2020 / NF DTU 68.3, duct sizing schedule, and unit selection against French-market models.
8-point NF DTU 68.3 compliance review. ABF / Déclaration Préalable check for listed properties. Grant eligibility confirmed.
Written report delivered within 5 working days. Installer-ready brief and MaPrimeRénov' dossier included. Yours to use with any contractor.
No. MVHR is increasingly specified in deep renovations of existing properties — particularly where insulation upgrades are raising airtightness beyond the point where natural ventilation is adequate. Older Dordogne farmhouses frequently need controlled ventilation after window replacement and wall insulation, regardless of build date.
Typically no, but it depends on your property's status. If your house is within the perimeter of a listed monument (périmètre ABF), any external penetration — including the MVHR intake and exhaust terminals — may require a Déclaration Préalable. This is checked as part of the audit. Properties in conservation areas (secteur sauvegardé) have additional constraints.
For MaPrimeRénov' eligibility, the installation must be carried out by an RGE-certified contractor (Reconnu Garant de l'Environnement). The audit report includes an installer brief designed to be taken to any RGE contractor of your choice — there is no obligation to use a specific company.
RE2020 is the French thermal regulation for new construction and major renovation, which sets minimum ventilation standards including airflow rates by room type and construction year. NF DTU 68.3 is the technical standard governing the design and installation of VMC systems. The audit calculates and checks your system against both frameworks and produces a compliance declaration suitable for building permit submissions.
The audit produces a duct sizing schedule with recommended diameters and a simplified zone plan showing supply and extract room allocations. Detailed duct routing — the physical path through walls, floors, and ceiling voids — is determined by the installer on site. The audit gives the installer the specification; they determine the best physical route for your property.
A chauffe-eau thermodynamique (CET) works by extracting heat from ambient air — from the utility room or garage — and is sometimes integrated with the MVHR extract circuit. The combined MVHR + CET assessment considers both systems together at a reduced combined fee. Both are separately eligible for MaPrimeRénov' grants. Check your eligibility →
The first conversation is short, no-charge, and without commitment. It is simply a chance to understand your property and whether an MVHR audit would be useful before you speak to any installer.