Which ventilation system to choose?

Why opt for an efficient ventilation system in the house?

You may have already heard that the air in your home is more polluted than the air outside. This is true because living in a house leads to the emission of pollutants: you, your animals, your plants, humidity… Ventilation and airing are necessary to keep the air clean.

But a natural ventilation system is not always easy to install, especially if it has not been integrated at the construction stage. Fortunately, several efficient ventilation systems can help keep your home pleasant and comfortable, such as CMV (controlled mechanical ventilation).

Above all, it is important to know that poor air renewal can lead to allergies, headaches, discomfort, and even illness. A home with too much moisture is also more likely to deteriorate, producing mould and weakening the whole structure.
In humidity-prone rooms (and others), it is essential to limit condensation and water vapour, which affect the quality of the air. Getting rid of VOCs (volatile organic compounds) and other pollutants by ventilation allows you to breathe healthy air at home all the time.

So opting for an efficient ventilation system in a house or a flat is not a luxury, it is (literally) an obligation (legal but not only)!

What are the different ventilation systems?

Natural ventilation, or mechanical ventilation… there are many different ways of ventilating the house. What are they and how do you choose them?

Natural ventilation, the cheapest and most energy-efficient system

The most common and natural ventilation system used at the time was simply natural ventilation of the rooms in the house. Before the widespread use of CMV and other mechanical systems, natural ventilation was popular for its efficiency at low cost and without energy consumption.

Rudimentary, taking advantage of thermal or wind draught and operating with ventilation grilles, it is a ventilation system that is still used, efficient and effective. Maintenance is minimal (annual cleaning of the ventilation grilles is sufficient) but it is sometimes difficult to install in renovation works.

How does natural ventilation work? Ventilation grilles are placed at the bottom of the building in the main rooms of the dwelling. This allows air to circulate upwards as its temperature rises and then to be released through the ventilation grilles, this time placed high up.
As easy as pie but far from being the most efficient, natural ventilation systems are now often replaced by CMVs.

CMV, the most widely used mechanical ventilation

Controlled mechanical ventilation or CMV comes in various forms.
Firstly, the most popular, the single flow CMV, which is cheap and easy to install in most houses and all types of housing. This single flow ventilation system is permanently active and can therefore generate draughts, noise, and heating losses… which is not ideal.
Secondly, humidity-sensitive CMV limits energy losses because the flow is not continuous but adapts. The airflow rate is modified according to the hygrometry of the environment of the CMV. The energy losses are thus lower than with a conventional single flow ventilation system, as the airflow is constantly adjusted.

Then, more complex and difficult to install but also more efficient, the double-flow ventilation system is based on 2 air circulation networks. With this unit, the fresh air from outside is heated before it reaches the rooms in the house. This means no draughts or energy losses. Humidity-controlled, capable of cooling in summer, and very efficient, it is also a more expensive solution than the others.

Note that the double-flow ventilation system can also be thermodynamic: this is one of the most efficient ventilation systems on the market. It combines a double-flow CMV and a geothermal heat pump to efficiently ventilate while pleasantly heating. Reversible, renewable energy, and free energy, the thermodynamic double-flow ventilation system is an excellent way to ventilate and heat at the same time.

CMV can also be gas-fired, especially in multi-family housing. As for the MVI, mechanical ventilation by insufflation principle, this system blows fresh air towards the interior of the house, filters it, and preheats it. Easy to install, the VMI effectively reduces the humidity levels but is more expensive than other mechanical ventilation systems.

DMV or OMV for distributed or One-shot mechanical ventilation

Finally, there is the last type of mechanical ventilation: distributed mechanical ventilation or DMV. Similar to a CMV, this system is older, less practical to install, and consumes energy that is not renewable. It is, therefore, best to avoid it if possible!

Thermal insulation renovation of the house, optimisation of energy consumption and heating, reduction of humidity in water rooms… there are many opportunities to install an efficient ventilation system. Don't wait any longer.

Costs vary, as does the ecological impact, but you can finance your home ventilation system with financial aid in some cases. Don't forget to compare offers and quotations to choose the best solution, the most suitable, the best value for money and if possible the most energy-efficient and responsible!