Powered ventilation that recovers heat from outgoing air; standard Passivhaus pairing with airtightness.
Cost
High
Upkeep
Seasonal
Skill to build
Specialist
Lifespan
15-30 years for the core unit; filters need replacement every 3-6 months, fans/motors are the usual mid-life failure point
Embodied carbon
Medium
Space / material use
Low
Output timing
On-demand/controllable
Skill to repair
Specialist
Regulation (FR example)
Dwellings must have general and permanent ventilation (arrete du 24 mars 1982, modifie). Mechanical ventilation is the usual way of meeting it in an airtight building.
Note: Cost, carbon and footprint are rated against the other options for this same need, not in absolute terms.
What your site needs
An airtight envelope, MVHR loses most of its value without it
No sizing or quantities: how much a technique yields, and how much a household needs, both depend on the build and the people, so the catalogue compares options rather than dimensioning them. It carries no bill of materials and no build sequence, and it is written for an oceanic, clay-soil climate (Normandy, France). Regulatory notes are indicative and need confirming locally.