Mechanical ventilation provides a constant supply of fresh air in many Dutch homes, without you having to open windows yourself. Below we explain exactly how this system works and what components are involved.
The basic principle
In mechanical ventilation, a fan extracts air from the rooms where most moisture and odours are generated: the kitchen, bathroom, toilet, and sometimes the laundry room. This air is vented outside through ducts, usually through the roof. Because air is being extracted, fresh air must also enter. In the most commonly used variant, this happens through ventilation grilles in the exterior walls or windows of the living rooms and bedrooms.
The main components
A mechanical ventilation system usually consists of a ventilation unit (containing the motor), a system of ducts, extraction points in the wet rooms, and a control switch. The control unit is often located in the kitchen or bathroom and has multiple settings, from low to high, so that you can temporarily increase extraction while cooking or showering, for example.
Natural supply versus balanced ventilation
The most common system in the Netherlands is mechanical extraction with natural supply: air is actively extracted, and fresh air enters through grilles without a motor. In balanced ventilation, also known as system D, the air is also actively supplied, often with heat recovery so that the incoming air is preheated using the heat from the extracted air.
Settings and controls
Modern systems are often demand-controlled: a sensor measures the CO2 concentration or humidity, and the fan automatically adjusts the extraction accordingly. This means that extra ventilation is only provided when necessary, which helps to reduce energy loss while maintaining good air quality.
Why this system is so common
Mechanical ventilation is popular because it provides a constant supply of fresh air, regardless of the wind or outdoor temperature. This is especially important in well-insulated and airtight homes, where natural ventilation often does not move enough air. The system does require maintenance: filters and grilles must be cleaned regularly, otherwise their capacity will decrease and the air may start to smell musty.
How can you tell if the system is working properly?
A properly functioning system is barely audible on the lowest setting and clearly moves more air on the highest setting, for example, when you can feel it at the grille in the bathroom while showering. If the house still smells musty despite the ventilation, or if condensation remains on the windows, this may indicate a clogged filter, a dirty grille, or a motor that is no longer running at full capacity.
Many residents do not know exactly what type of system is installed in their home. A look at the control switch, usually in the kitchen or bathroom, often gives a clue: a simple switch with settings usually belongs to mechanical extraction with natural supply, while a thermostat-like control panel with a temperature or CO2 display usually belongs to balanced ventilation.
A properly functioning ventilation system is the foundation of a healthy indoor climate, but it is not the only thing that matters. Fine dust, pollen, and household dust also continue to enter through windows and doors. If you want to address this further, you can look at solutions at Dynter that further support the air quality in your home.