Ventilation systems in comparison - the inVENTer-Check
Overview of the advantages and disadvantages of ventilation systems
Controlled air exchange is essential in modern, energy-efficient buildings. At the same time, builders and planners are faced with a wide range of technical options: from central ventilation systems to decentralized devices and simple window solutions. But how do these systems differ in concrete terms—and which one is suitable for which application? The following comparison highlights the functionality, planning, costs, and areas of application of the various ventilation systems.
Why is controlled ventilation necessary today?
The Building Energy Act (GEG) requires that newly constructed buildings be designed in such a way that the minimum air exchange necessary to protect health and ensure heating is guaranteed (Sections 13, 15, and 28 GEG). This necessary air exchange is already taken into account in energy planning, for example in heating load calculations.
In practice, the specific ventilation design is carried out in accordance with DIN 1946-6. The background to these requirements is the increasing airtightness of building envelopes, which reduce energy losses but hardly allow any natural air exchange through joints. The required air exchange must therefore be ensured in a targeted manner by suitable ventilation systems in order to prevent moisture damage and mold growth.
Ventilation systems ensure continuous and controlled air exchange in buildings. To achieve this, the supply and exhaust air volumes must be balanced, which is often difficult with decentralized ventilation systems. The decentralized systems are integrated into the exterior wall. While one unit extracts stale, warm air from the room to the outside, the second unit simultaneously supplies fresh air from outside. The ventilation units switch functions at set intervals, resulting in a periodic change between exhaust and supply air operation. The inVENTer portfolio includes, for example, the iV-Zero or the iV-Smart+.
With central ventilation, a central unit supplies fresh air to all living spaces via an air distribution system. It is installed in a storage room, for example, while the air ducts can be discreetly routed through suspended ceilings. Typical solutions based on this principle from inVENTer are the Centra 150 and Centra 250, which supply the building with fresh air in a controlled and uniform manner. Central systems are not only suitable for residential buildings, but also for larger spaces such as schools, daycare centers, or other commercial units.
In addition to mechanical ventilation systems, forms of free ventilation, such as window rebate ventilation, are also among the options for air exchange. These consist of simple ventilation slots in the window frame and enable passive air flow. Regardless of the ventilation option chosen, early and careful planning of ventilation during construction or renovation measures is crucial. The advantages and disadvantages of the various ventilation systems are examined in more detail below.
Which ventilation system is the best?
The best ventilation system always depends on the specific application. There is no ventilation system that is equally suitable for all buildings and usage scenarios. Both central and decentralized systems have specific strengths and areas of application that result from structural conditions, the type of building, and the requirements for planning and installation. Therefore, it is not the systems themselves that are decisive, but rather a professional and needs-based selection. While decentralized systems are particularly impressive due to their flexibility, central ventilation systems demonstrate their strengths especially when it comes to holistic comfort and efficiency requirements.
The respective product overviews for decentralized ventilation systems and central ventilation systems, which cover different requirements and areas of application, provide an overview of typical designs and system solutions.
1. Installation & planning of ventilation systems in comparison
The following overview compares the installation effort and planning requirements of different ventilation systems. The focus is on installation flexibility, structural requirements, and necessary expertise.
2. Features of ventilation systems in comparison
This table compares the technical characteristics of ventilation systems – from energy efficiency and noise levels to sensor technology. It shows which systems offer long-term comfort and savings potential.
3. Practical use of ventilation systems in comparison
This overview highlights the differences in the daily operation of the ventilation systems. It takes into account aspects such as control, maintenance requirements, and running costs.
Advantages and disadvantages of window rebate ventilation
- Cost-effective solution for easy air exchange
- Easy installation directly in the window frame
- No power connection required
- Low maintenance and easy to clean
- Enables basic fresh air exchange and can prevent mold growth
- No controlled airflow
- No heat recovery
- Continuous heat loss through uninsulated openings
- Only works with sufficient natural airflow (e.g., opposite facades)
- Often limited effectiveness in practice
- May promote cooling and moisture problems in unfavorable conditions
Classification:
Window rebate ventilation systems are a simple and cost-effective way of enabling basic air exchange. They meet the requirements of DIN 1946-6 for user-independent ventilation for moisture protection and can be particularly useful in buildings with low ventilation requirements or as a supplementary measure, for example to reduce moisture peaks.
However, due to the lack of control over air flow, air volume, and heat recovery, these systems are not suitable as a sole solution for permanent, demand-based, and energy-efficient air exchange. In addition, window rebate ventilators do not replace manual window ventilation for nominal or intensive ventilation.
Advantages and disadvantages of the central ventilation system
- Centralized and uniform supply of fresh air to all rooms
- Precise control of air exchange rates for the entire building
- Central control of air volume, humidity, and temperature
- Overall balanced heat and moisture balance in the building
- Targeted removal of exhaust air from the kitchen, bathroom, and toilet
- High energy efficiency through heat recovery
- Effective filtering of the supply air (e.g., dust, pollen, fine dust)
- Option for temperature-controlled or pre-conditioned supply air (e.g., cooling in summer)
- Very quiet operation thanks to air silencer and central technology
- Ideal for new buildings and larger buildings
- Higher planning costs
- Higher investment costs
- Retrofitting in existing buildings only possible with major construction work
- Regular cleaning of air ducts required for hygienic reasons
Classification:
Central ventilation systems operate with a centrally located ventilation unit that supplies fresh air to all rooms in a building via a shared air duct system and extracts stale air in a controlled manner. They offer a comprehensive and convenient solution for controlled residential ventilation. Their strengths are particularly evident in new buildings or comprehensive renovations, where the system is integrated into the building design from the outset. In such applications, they enable even air distribution, high energy efficiency, and very quiet operation, but require careful planning and regular maintenance of the air ducts. In single-family homes and apartment buildings, compact central ventilation units such as the Centra 150 or 250 from the Centra series by inVENTer are often used, which enable uniform ventilation of all living spaces via a central air distribution system.
In addition, central ventilation systems are particularly suitable for buildings with high requirements in terms of air quality, comfort, and energy efficiency. Central control allows air volumes, humidity, and temperature to be optimally coordinated, which contributes to stable and consistent indoor air quality, especially in larger residential buildings.
Decentralized ventilation: advantages and disadvantages
- Fresh air supply with heat recovery via ceramic heat storage
- High energy efficiency with low power consumption
- Comparatively low acquisition costs
- Quick and flexible installation
- Can be used in both new and old buildings
- Maintenance and cleaning can usually be carried out by the user themselves
- Possible noise generation from external and internal sound
- Sound insulation depends on device design and structural conditions
- Maintenance costs are spread across several individual devices
- Central air conditioning or conditioning of the supply air only possible to a limited extent
- Cannot usually be installed if exterior walls are missing or facades are fully glazed.
Classification:
Decentralized ventilation systems are characterized by their high flexibility and can be installed relatively easily in both new and existing buildings. Decentralized systems are particularly suitable for renovation projects, individual residential units, or buildings with limited structural possibilities. Combining heat recovery, low energy consumption, and easy maintenance, they represent an efficient solution whose acoustic properties depend largely on the choice of equipment and the structural situation. However, there are also numerous sound insulation measures available to minimize internal and external noise. For special requirements, such as larger rooms or increased air exchange requirements, more powerful single-room units such as the X-Flow are available, which can also be used flexibly in renovations.
Decentralized residential ventilation systems offer significant advantages in many applications, particularly due to their flexible usability, comparatively simple installation, and efficient heat recovery. They have therefore established themselves as a practical and energy-efficient solution, especially in renovations, individual residential units, or buildings with structural limitations, which is also reflected in rising demand.
Central ventilation systems, on the other hand, offer a highly efficient long-term solution, especially in new buildings or comprehensive renovations. They enable even air distribution throughout the entire building, central control of air quality, and high energy efficiency, making them particularly suitable for larger buildings and demanding usage concepts. For larger residential or functional buildings with high requirements for air quality and controllability, more powerful central systems are also used, such as the Centra 1000, which is also used in educational institutions and apartment buildings.
Nevertheless, there is no ventilation solution that is equally suitable for all buildings and usage scenarios. Both central ventilation systems and simpler forms of ventilation fulfill their function in certain applications and can be used effectively with appropriate planning. It is always crucial to select systems that are tailored to the specific needs, taking into account the structural conditions, the type of building, and individual requirements.