Controlled Mechanical Ventilation (CMV)

Single-flow ventilation

The function of a single-flow CMV system is to ventilate the house.

It is composed of:

• an exhaust unit
• air inlets
• exhaust vents.

Fresh air enters the house through air inlets positioned at the windows and it is expelled by the exhaust vents located in the “wet” rooms i.e. kitchen, bathroom, toilet or laundry.

Working principle

There are two systems:

• Self-adjusting:
  The components have a “self-adjusting” operation because they operate mainly by pressure differential to vary the air flow rates. The exhaust units have two operating speeds: one constant to ventilate the house constantly and the second faster to extract more air flow when preparing meals in the kitchen.
• Humidity-controlled:
  The operation is similar to a self-adjusting operation except that the flow rates are varied according to the relative humidity. The humidity detection system makes it possible to adjust the unit’s speeds, thereby reducing electrical consumption.

Benefits

Self-adjusting system:

• Renews the indoor air
• Prevents the appearance of mould in bathrooms thanks to air extraction from wet rooms
• Quite silent

Humidity-controlled system:

• Renews the indoor air
• Low consumption due to control based on the humidity level
• Prevents the appearance of mould in bathrooms thanks to air extraction from wet rooms
• Quite silent

Mechanical supply and exhaust ventilation

Mechanical supply and exhaust CMV units renew the indoor air with fixed flow rates, which match the needs of your home.

A mechanical supply and exhaust ventilation unit is composed of several components:

• Two separate duct networks, the first blowing fresh air into the living areas (living room and bedrooms), the second expelling stale air from the “wet” rooms (kitchen, bathroom and laundry).
• Inlet grills to diffuse fresh air and vents to extract stale air
• An air inlet for fresh air and an air outlet for stale air
• A supply and exhaust unit

A supply and exhaust unit contains

• two fans to allow air intake on one hand and air extraction on the other.
• a heat exchanger that recovers heat from the extracted air to transfer it to the incoming air. It is associated with a condensate recovery system that must be connected to the waste water system because the exchanger naturally produces water vapour.
• filters
• regulation to optimise the operation

Working principle

A mechanical supply and exhaust ventilation unit ensures both the extraction and supply of outdoor air in the living areas.

A heat exchanger makes it possible to cross the incoming fresh air and the outgoing stale air, without mixing the flows. The mechanical supply and exhaust ventilation unit can thus preheat the fresh air before it is diffused into the rooms in the house.

By stirring the air in the house and reusing the calories present in the extracted air, the mechanical supply and exhaust ventilation unit can save money and avoid the discomfort associated with the feeling of incoming cold air.

Also with its filters, the mechanical supply and exhaust ventilation unit improves the quality of indoor air:

1. on the heat exchanger side, the filter protects the unit against the risk of fouling
2. on the injection side, the filter curbs the entry of dust or pollen or other allergens into the living areas.

In winter, the mechanical supply and exhaust ventilation unit saves energy as the incoming air is preheated by the outgoing air. In summer, as the bypass is open, it is not necessary to heat the incoming air.

Air quality is ensured through the operation of the mechanical supply and exhaust ventilation unit which maintains the flow rates adjusted to the home’s needs with protection against indoor and outdoor pollutants through filters.

Benefits of a mechanical supply and exhaust ventilation unit

• Renewing air in the home while saving energy
• Purifications of wet rooms by eliminating mould problems
• Energy savings:
  • The exchanger recovers the heat lost in the case of a simple extraction
  • The power consumption is low
• Acoustic comfort because the flows are controlled according to the needs, and so the sound levels are low.
• Improvement of indoor air the through controlled, permanent air renewal combined with effective filtration to fight against pollutants, both perceptible and hidden.

Compare to make the right choice

It is very easy to make the right choice: just compare the products. But when product performance is not certified, this becomes impossible.

Certification makes it possible to compare objectively.

• The product performance is evaluated according to the same criteria, and the results are expressed in the same unit of measurement, regardless of the country where the products are manufactured or marketed.
• A certified product has its performance verified by an impartial, independent and competent accredited body.
• Certified products comply with standards.
• A product whose performance is certified will work according to the specifications stated by the manufacturer.

The performances and characteristics we certify

Single-flow humidity controlled ventilation

Self-adjusting exhaust vents

• Air flow performance
• Acoustic isolation (for double-flow vents)
• Sound power level

Self-adjusting air inlets

• Air flow performance
• Acoustic isolation

Single-flow and mechanical supply and exhaust CMV

• Scope (Type of housing by number of rooms, and Room type (Bathroom, WC, utility room, Kitchen)
• Sound power level (noise) (dB)
• Consumption in watt

Related technical insights