VMC vs VMI: Which Ventilation to Choose?
When dealing with a humidity problem, ventilation is often the first solution to consider. But between VMC and VMI, which one should you choose? A complete comparison to make the right choice.
Understanding the fundamental difference
The VMC (Mechanical Extract Ventilation) works by extraction: it sucks stale air from wet rooms (kitchen, bathroom, toilets) and creates negative pressure that draws fresh air in through air inlets in dry rooms.
The VMI (Positive Pressure Ventilation) works in reverse: it supplies filtered and preheated fresh air, creating overpressure that naturally pushes stale air outside.
VMC: Pros and Cons
Points forts
- Most widespread and proven system
- Moderate installation cost (500-2000€)
- Effective for removing humidity
- Double flux: heat recovery
- Low power consumption
Points faibles
- Requires a network of ducts
- Can create negative pressure in the home
- Regular filter maintenance required
- Possible noise if poorly installed
VMI: Pros and Cons
Points forts
- Simple installation without duct network
- Creates overpressure (prevents parasitic air intake)
- Filtration of incoming air
- Air preheating possible
- Ideal for renovation
Points faibles
- Higher cost (2000-4000€)
- Higher electrical consumption
- Less effective in summer
- Does not recover heat from outgoing air
Comparison Table
| Criterion | Single-Flow VMC | Double-Flow VMC | VMI |
|---|---|---|---|
| Installation price | 500-1,500 € | 3,000-7,000 € | 2,000-4,000 € |
| Annual consumption | 30-50 € | 50-100 € | 100-200 € |
| Heat recovery | No | Yes (up to 90%) | Partial |
| Air filtration | No | Yes | Yes |
| Renovation ease | Average | Complex | Simple |
Which Solution for Your Situation?
New construction or major renovation
Opt for a double-flow VMC. More expensive to install, it allows for significant heating savings and offers optimal comfort.
Light renovation, limited budget
The humidity-controlled single-flow VMC is an excellent compromise: efficient, economical, and adaptable to most configurations.
Old house, porous walls, allergies
The VMI is ideal: simple installation, filtered air, and the overpressure prevents cold air infiltration through porous walls.
Sources et références
Cet article s'appuie sur des sources officielles et vérifiées pour garantir la fiabilité des informations.
- [1]
- [2]Indoor air quality— ANSES
Rédaction ZeroHumi
Équipe éditoriale ZeroHumi
Documentation technique vérifiée à partir des sources citées (ADEME, ANSES, OMS, CSTB, CEREMA)