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Back to Knowledge Hub30.06.2026
Thoughtful airflow routing is essential to the performance of a ventilation system. It determines how fresh air is distributed throughout a building, how reliably humidity and pollutants are removed, and whether a comfortable indoor climate can be maintained without drafts.
Whether for new construction or renovation, efficient and comfortable heat recovery ventilation is only achieved when airflow, air exchange, pressure conditions, and the correct positioning of the ventilation systems work together.
In this article, you’ll learn the fundamental principles of airflow routing, the most common planning mistakes to avoid, and the key considerations when designing decentralized ventilation systems.
Airflow routing determines how fresh air is distributed throughout a building and how reliably stale air is removed. It is therefore a fundamental component of every controlled residential ventilation system. Even high-performance ventilation systems cannot deliver their full benefits if airflow, air distribution, and system placement are not properly coordinated.
Well-designed airflow routing ensures that fresh air is supplied directly to occupied rooms while humidity, CO₂, and odors are continuously removed from kitchens, bathrooms, and utility rooms. At the same time, it prevents drafts and creates a consistently comfortable indoor climate.
In modern airtight buildings, the ventilation system performs functions that were previously provided by uncontrolled air leakage or regular window ventilation. To ensure a hygienic air exchange over the long term, air must follow the intended airflow paths.
Thoughtful airflow routing directly affects several important factors:
Not only the airflow rate but also the way air moves through a room is important. Even minor changes in the placement of supply air and exhaust air openings can significantly influence airflow patterns.
Optimal airflow does not happen by chance. It is established during the building design process. Important planning considerations include:
The positioning of the systems is especially important in decentralized ventilation systems. Because each system is installed directly through the exterior wall, its installation location largely determines how air is distributed throughout the room and whether the required air exchange is achieved. Careful planning minimizes later modifications while simplifying installation and ensuring economical operation. This reflects the approach of adapting ventilation solutions to each construction project during the planning phase.
A common misconception is that higher airflow rates automatically result in better ventilation. In reality, perceived comfort is determined primarily by air velocity within occupied areas.
If air moves too quickly or is directed at occupants, drafts can occur—even when temperature and airflow comply with technical specifications. The objective of effective airflow routing is therefore to create a gentle, barely noticeable air movement that allows fresh air to spread gradually throughout the room while stale air is reliably removed.
This balanced airflow pattern is especially important in bedrooms and living areas, where it significantly contributes to occupant comfort.
Controlled residential ventilation ensures that fresh air is supplied directly to occupied rooms while stale air is removed from moisture-prone rooms. To achieve reliable performance, air exchange, airflow, and pressure conditions must work together.
Air exchange describes how often the air within a room is replaced over a given period of time. It helps maintain consistently high indoor air quality while protecting the building structure.
Adequate air exchange ensures that:
In residential buildings, air is intentionally directed from supply air rooms to exhaust air rooms. Fresh air is supplied to living rooms and bedrooms, for example, before flowing through hallways or door undercuts into kitchens, bathrooms, or restrooms, where the stale air is exhausted outdoors.
This airflow concept offers several advantages:
Controlled ventilation systems operate with slight pressure differences to generate the desired airflow. Air is distributed evenly throughout the building only when airflow rates, pressure conditions, and airflow paths are properly coordinated.
Effective airflow routing is therefore always based on the interaction of:
Effective airflow routing is based on clearly defined airflow paths. The objective is to deliver fresh air to areas where occupants spend most of their time while removing stale air from spaces where humidity, odors, or pollutants are generated.
For this reason, supply air rooms and exhaust air rooms should already be defined during the planning stage.
Fresh air is typically supplied to the following rooms:
Exhaust air is removed from rooms where humidity or odors are regularly generated:
This arrangement creates controlled airflow throughout the building.
To allow air to follow its intended path, the individual rooms must be connected through transfer air paths, such as door undercuts or dedicated transfer air elements.
If these connections are missing or undersized, airflow can be restricted, resulting in uneven air distribution and reduced performance of the ventilation system.
Effective air distribution depends on much more than the location of individual ventilation systems. The interaction of all system components is what matters most.
Important planning considerations include:
Carefully planned airflow routing provides the foundation for efficient air exchange and consistently high living comfort. The following sections take a closer look at system placement and practical measures for preventing drafts.
A controlled residential ventilation system should provide fresh air without creating uncomfortable airflow. Occupant comfort therefore depends not only on the airflow rate but also on air velocity and the location of the air outlets.
Even slight air movement can be perceived as a draft if it continuously impacts occupants. Careful airflow planning helps prevent these issues from the outset.
Drafts usually occur when fresh air enters the room at excessive velocity or from an unfavorable direction. Common causes include:
This can significantly reduce comfort, particularly in living rooms and bedrooms.
The objective of effective airflow routing is to distribute fresh air evenly throughout the room. Air should spread gently and without drafts before flowing toward the exhaust air area.
The following factors are particularly important:
Uniform air distribution not only improves comfort but also supports efficient air exchange throughout the living space.
In most cases, drafts can be prevented during the planning stage. When airflow routing, airflow rates, and system placement are coordinated with the floor plan from the beginning, balanced airflow conditions and a consistently comfortable indoor climate can be achieved.
With decentralized ventilation systems, selecting the right installation location is especially important. The position of the system has a major impact on how fresh air is distributed throughout the room—and therefore on whether comfortable, draft-free ventilation can be achieved.
The placement of ventilation systems has a significant influence on airflow routing throughout the building. Only when supply air and exhaust air openings are strategically positioned can air be distributed evenly and a comfortable indoor climate be maintained.
Fresh air is supplied to occupied rooms, while exhaust air is removed from moisture-prone rooms.
Typical supply air rooms:
Typical exhaust air rooms:
This creates controlled airflow throughout the building.
Because decentralized ventilation systems are installed directly through the exterior wall, their installation location is especially important. The following factors should be considered during planning:
Careful positioning supports even air distribution, improves living comfort, and simplifies future installation and maintenance.
Decentralized ventilation systems provide controlled air exchange without requiring a central duct network. Each system supplies fresh air directly to its respective room or exhausts stale indoor air outdoors. This makes them particularly well suited for renovation projects, individual living areas, or buildings where installing a centralized system would require significant effort.
Many decentralized ventilation systems operate according to the push-pull principle. In paired operation, two systems alternate between supply air and exhaust air. While one system supplies fresh outside air, the other exhausts stale indoor air. After a defined period, both systems switch functions.
This:
To achieve optimal airflow routing, decentralized ventilation systems should be coordinated with the building layout and room usage. Important considerations include:
The result is a balanced indoor climate with high indoor air quality and excellent living comfort.
Even minor planning mistakes can impair airflow routing and reduce living comfort. Coordinating airflow routing, system placement, and airflow rates early in the planning process helps prevent problems later.
The most common mistakes include:
Careful planning ensures that fresh air reaches every occupied room while stale air is reliably removed. This creates the ideal balance between comfort, energy efficiency, and consistently high indoor air quality.
Thoughtful airflow routing is the foundation of comfortable and efficient residential ventilation. It ensures that fresh air is distributed where it is needed, stale air is reliably removed, and drafts are avoided.
The following points should therefore be considered during the planning stage:
Especially in decentralized ventilation systems, proper system placement plays a key role in achieving uniform air distribution and a high level of living comfort. When airflow routing is incorporated into the planning process from the beginning, comfort, energy efficiency, and consistently high indoor air quality can be optimally combined.
We support consulting engineers, architects, and contractors with customized ventilation solutions—from decentralized ventilation systems and practical planning documentation to technical consulting. This enables ventilation concepts to be planned efficiently and implemented cost-effectively.
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We provide architects and technical planners tailored solutions to address every ventilation challenge with precision. Whether it is sound insulation, energy efficiency, or optimising facade aesthetics, our expert technical teams are equipped to provide you with the ideal solutions.
With Ventomaxx, you gain access to comprehensive hybrid ventilation concepts that seamlessly combine passive and active systems from a single, trusted source. Our mission is to improve indoor air quality in the most efficient way.
We provide architects and technical planners tailored solutions to address every ventilation challenge with precision. Whether it is sound insulation,
energy efficiency, or optimising facade aesthetics, our expert technical teams are equipped to provide you with the ideal solutions.
With Ventomaxx, you gain access to comprehensive hybrid ventilation concepts that seamlessly combine passive and active systems from a single, trusted source. Our mission is to improve indoor air quality in the most efficient way.
