Central ventilation system: functions, planning and installation

In the simplest configuration, stale air is actively drawn in by a fan and expelled outside. Air diffusers in such systems are typically located in exhaust ventilation zones. These include the kitchen, bathroom, and toilet, which tend to have higher humidity and unpleasant odors than living spaces such as living rooms or offices. Fresh air, on the other hand, enters the home only passively through diffusers in the building envelope, window, and door openings.

In practice, mechanical ventilation systems that actively draw in both supply and exhaust air are often used. These combined supply and exhaust ventilation systems feature a central ventilation unit and an air distribution system. Not only is stale air actively drawn in and removed, but fresh air is also actively introduced into the home. To prevent unwanted airborne particles and noise, most systems are equipped with filters.

To more accurately calculate the required ventilation, it’s necessary to consider the number of rooms and occupants, as well as their usage patterns. Therefore, regardless of the application, homeowners should always entrust the planning and implementation of a mechanical ventilation system to a contractor. They can accurately determine how large a ventilation system should be to ensure maximum efficiency. In the next section, you can read about other considerations homeowners and remodelers should take into account when choosing the right ventilation system.

In existing buildings that haven’t been modernized, fresh air enters the home passively through leaky building cladding, door cracks, and window gaps. However, using a ventilation system in such buildings is a good idea, as the risk of mold formation is still very high. However, central ventilation is rarely feasible in older buildings that haven’t been modernized. This is because it requires significant planning, which is generally only practical during the construction or modernization phase. In principle, it’s important to note that while central ventilation is possible in older buildings, its installation will be more complex. This is because it requires structural modifications. Furthermore, the air ducts must be lined.

Central ventilation systems are often used in new buildings. They are installed early in the construction phase, even when the building is still incomplete. Once the building is completed, they are no longer visible. Therefore, a central ventilation system in a new building should always be planned in advance. For residential buildings, a ventilation concept according to DIN 1946-6 is developed for this purpose. The ventilation system is used to ensure the minimum air exchange rate associated with health risks and to protect the building. Most building owners choose central ventilation during the construction phase. This is usually sensible, but not always necessary. With optimal planning and implementation, decentralized mechanical ventilation can also effectively supply new buildings with fresh air.

This type of installation is often used in new buildings. In this case, flat ducts are first laid directly on the unprepared floor, followed by insulation. If necessary, underfloor heating pipes are laid over this, followed by a final layer of screed. After this, the air ducts are no longer visible. Only floor or ceiling diffusers indicate the presence of a ventilation system underneath.

An alternative to installing air ducts on unfinished floors is installation in concrete. For this purpose, round air ducts are typically placed within the steel ceiling reinforcement during the initial construction phase. Only then is the concrete poured. This installation method is suitable for both partially finished ceilings and concrete ceilings poured in place. The advantage of this installation is that no additional floor structure is required. However, detailed preliminary planning with a design engineer is necessary.

Depending on the room’s height, ventilation systems can also be installed in suspended ceilings. The Vitovent 200-C and Vitovent 300-C flat ceiling units are particularly suitable for this purpose. These units can be mounted directly to the ceiling. The air ducts leading to individual rooms are integrated into the suspended ceiling, making them invisible.