How to choose your ventilation system


It is impossible to ignore ventilation during energy-efficiency improvements or LCB and passive house construction. However, how to determine, among the numerous available systems, the one better suited to your needs? We help you make the right choice in the following sections! 




There is no serious energy-efficiency improvements or new building construction without ventilation system. Especially as it greatly improves the isolation and air tightness of the building. Why ventilate? For your health and comfort! Indeed, a ventilation system ensures the air renewal and stale air extraction. It guarantees the hygiene of your home, prevents moisture development, contributes to energy savings and complies with safety criteria: air supply and extraction for heating appliances, firefighting and acoustic comfort standards.


In existing constructions, the design and installation of a ventilation system is more complex than in new ones. It requires a serious assessment of the existing situation. Depending on the type of dwelling, house or apartment, the solutions will not be the same. If there is already a ventilation system, its performance must be evaluated. This study will allow to assess the thermal behaviour of the project. What are the heat losses? Which are related to the ventilation system? How does the building behave during the summer season? Etc. It is the only way to validate the ventilation solution for its potential impact on energy consumption and air exchange rate. Good to know: a ventilation system improperly sized, where the airflow is too high, will lead to overconsumption.


Four options are possible: controlled mechanical ventilation (CMV) single flow hygro-adjustable or not, dual flow CMV, thermodynamic water heater on dumped air or even distributed mechanical ventilation.


The principle is simple: the outside fresh air is distributed in the main rooms (living room, bedrooms...). The air circulation is possible thanks to a system of air ducts towards the sanitary rooms (kitchen, bathroom, WC...). The used air is evacuated outside through air outlets. It is an efficient system! The only drawback, in particular in winter time: the expelling of heated air outside leads to an increased energy consumption. The solution? The single flow hygro-adjustable VMC. Thanks to its air inlets and/or outlets, fitted with «hygro-adjustable» vents that open according to the ambient humidity level, it detects the presence or absence of people in the rooms. It is far more efficient. Two options are possible: A type with hygro-adjusting outlets or B type with hygro-adjustable air inlets and outlets.


With the dual flow CMV, the air intake and extraction are ensured by mechanical devices. Major asset: the intake air is preheated by a heat exchanger that recovers heat from the exhaust air. This leads to heating energy savings. The air inlets are installed in the main rooms whereas the air outlets are located in the sanitary rooms. A solution adapted to major renovations aiming at reaching the LCB performance level. It is possible to connect it to a Canadian well. Weakness: The important renovation required in order to install the dual-duct system and the need for a technical room. It is also the most expensive option.



This compact 2-in1 product takes care of your domestic hot water and home ventilation. It is made of one thermodynamic water heater and one hygro-adjustable controlled mechanical ventilation. Benefits of this technology: significant energy savings, the hot water is produced at a lower cost thanks to the recovery of the heat from the hot air being expelled (by the ventilation system). You can expect about 70 % savings on your domestic hot water bill! It is also an environmentally friendly option.