One small unit per room instead of a central ducted system; easier to repair or replace individually if one fails.
Cost
Medium
Upkeep
Seasonal
Skill to build
Intermediate
Lifespan
15-25 years for the core unit; filters need replacement every 3-6 months, same profile as central MVHR
Embodied carbon
Medium
Space / material use
Low
Output timing
On-demand/controllable
Skill to repair
Intermediate
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.
MVHR and small-wind-turbine lifespan industry sources (Envirovent, Ventsolve, Automaxx, RenewableEnergyHub)
What this page does not tell you
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.