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Back to Knowledge Hub16.06.2026
The energy-efficient renovation of existing buildings is fundamentally changing the requirements for building ventilation. While new windows, insulated facades, and improved air tightness reduce energy consumption, they also decrease natural air exchange. Humidity, CO₂, and other airborne pollutants remain inside the building longer and can negatively affect both occupant comfort and the building structure over time.
While window ventilation was once widely considered sufficient, modern renovation standards increasingly require planned, user-independent ventilation solutions. This presents a particular challenge in existing buildings: the existing building structure often allows only limited modifications, while project effort, costs, and construction time must remain manageable.
Modular ventilation systems offer a practical solution. Their flexible design allows them to be adapted to different building types, renovation scopes, and technical requirements. Individual components can be combined, expanded, or integrated in different construction phases as needed. This creates ventilation concepts that address both technical and economic requirements.
This article explains how modular ventilation systems work, the advantages they offer for the renovation of existing buildings, and which system components should be considered during planning.
Modular ventilation systems consist of individual, coordinated components that can be flexibly combined depending on the building, its use, and the scope of renovation. Unlike rigid, all-in-one systems, they allow for demand-based planning and can be adapted to the specific requirements of each project.
The basic principle is to combine different functional modules into an individual ventilation concept. Depending on the requirements, components such as passive airflow supply (system) (PAS), ventilation systems with heat recovery (HRV), supply and exhaust air solutions, or preconfigured installation components can be used and combined.
Not every building requires the same ventilation solution. While apartment renovations often focus on individual rooms, larger existing buildings frequently require consideration of different usage areas.
Modular systems make it possible to tailor ventilation to actual requirements. Individual components can be installed precisely where they are needed. This results in solutions that are neither oversized nor unnecessarily complex.
Another advantage is that future modifications remain possible. If a building is expanded, repurposed, or renovated in additional construction phases, the ventilation concept can often be extended with relatively little effort.
Particularly in the renovation of existing buildings, project conditions are rarely standardized. Different wall constructions, limited installation space, or historic preservation requirements often call for customized solutions.
Modular ventilation systems provide additional flexibility:
For planners and contractors, this means greater flexibility during project execution. At the same time, building owners benefit from a solution that adapts to the actual needs of the building and can evolve over the long term.
This flexibility is precisely what makes modular ventilation systems particularly suitable for the energy-efficient renovation of existing buildings.
In many renovation projects, measures such as window replacement, facade insulation, or roof renovation are the primary focus. These measures significantly improve a building’s energy efficiency. At the same time, however, they also affect the air tightness of the building envelope and therefore the conditions required for sufficient air exchange.
If ventilation is not considered early in the planning process, new issues may arise despite a successful energy-efficient renovation. Humidity remains in the building longer, pollutants are removed less effectively, and indoor air quality can noticeably decline.
Modern windows and insulated building envelopes reduce uncontrolled heat losses. At the same time, however, a large portion of the natural air exchange rate that older buildings experienced through leakage is eliminated.
This creates a conflict of objectives: on the one hand, energy losses should be minimized; on the other hand, sufficient fresh air must continue to enter the building.
A planned ventilation concept helps balance these two requirements.
Daily activities such as showering, cooking, laundry, and simply occupying a space continuously generate moisture loads. If this humidity cannot be reliably removed, the risk of condensation and long-term building damage increases.
In addition, enclosed spaces accumulate:
Controlled ventilation provides the necessary air exchange and helps maintain a permanently healthy indoor climate.
Sustainable building technology considers not only a building’s energy consumption but also its long-term usability and value retention.
A modern ventilation concept supports several objectives simultaneously:
In particular, systems with heat recovery (HRV) make it possible to combine necessary ventilation with high energy efficiency.
Experience shows that ventilation is often only considered once moisture problems or comfort issues have already occurred. However, from both an economic and technical standpoint, it is more effective to incorporate ventilation into renovation planning from the very beginning.
This allows the building structure, usage, energy-efficiency measures, and ventilation technology to be optimally coordinated. The result is a solution that not only meets current requirements but can also accommodate future changes in use and building expansions.
Particularly in existing buildings, modular ventilation systems provide a flexible foundation because they can be adapted to different building conditions and implemented step by step.
Renovation projects differ fundamentally from new construction. Existing building structures, limited space, and varying building conditions require solutions that can adapt flexibly to project-specific constraints. This is exactly where modular ventilation systems demonstrate their strengths.
Instead of integrating a rigid, comprehensive system into the building, individual components can be installed precisely where they are technically appropriate and economically feasible. The result is a ventilation concept that adapts to the building—not the other way around.
Many renovation projects are not completed in a single construction phase. In many cases, individual apartments, building sections, or usage units are modernized first, while other areas follow at a later stage.
Modular ventilation systems support phased implementation. Individual components can be integrated during the early stages of a project and expanded later as needed. This keeps investments predictable and allows the building’s technical systems to evolve alongside the renovation measures.
For owners and investors, this provides additional flexibility when planning budgets and construction schedules.
Hardly any two existing buildings are identical. Different wall constructions, room layouts, and technical conditions often make it difficult to standardize ventilation solutions.
Modular systems make it possible to adapt the ventilation concept to the specific building situation. Depending on the requirements, different components can be combined to create a technically and economically suitable solution.
Especially in complex renovation projects, this flexibility reduces planning effort and simplifies implementation.
Buildings change over the course of their lifecycle. Changes in use, expansions, or additional modernization measures can create new requirements for ventilation technology.
A modular design provides the necessary flexibility. Additional ventilation components can often be integrated more easily than with fully closed system concepts. This keeps the building technology adaptable and able to respond to future requirements.
This scalability is a particularly important advantage for larger residential and commercial properties.
In addition to planning, practical implementation plays a decisive role in project success. Prefabricated system components and coordinated installation solutions can simplify installation processes and improve execution quality.
For example, preconfigured wall mounting solutions support faster installation of ventilation components and help reduce coordination points on the job site. At the same time, contractors benefit from clearly defined installation conditions and reduced coordination effort.
This creates significant added value for planners, contractors, and building owners: ventilation technology can be integrated into the renovation process more efficiently without creating unnecessary complexity or extending construction schedules.
The strength of modular ventilation systems lies in their flexible design. Instead of relying on a rigid overall concept, different components can be combined according to project requirements. This creates ventilation solutions that can be tailored to the building’s requirements, the renovation scope, and the desired level of system expansion.
Depending on the project, different system components are used, each fulfilling specific functions within the overall ventilation concept.
Passive airflow supply (system) (PAS) components often form the foundation of controlled ventilation. They provide a regulated fresh air supply and ensure that the required airflow is delivered independently of occupant behavior.
Particularly in buildings with high air tightness, they help maintain the necessary air exchange rate and prevent moisture-related damage. At the same time, modern systems enable draft-free airflow routing and can contribute to improved occupant comfort.
In energy-efficient renovation projects, ventilation systems with heat recovery (HRV) play a central role. They utilize the thermal energy contained in the exhaust air to preheat incoming outside air.
This provides the necessary air exchange without losing valuable heating energy through open windows.
For renovation projects, this offers several advantages:
Particularly in modernized building envelopes, heat recovery can make a significant contribution to overall energy efficiency.
Supply and exhaust air systems provide targeted airflow routing throughout the building. While stale and humid air is removed from areas with higher pollutant loads, fresh outside air is supplied in a controlled manner to occupied spaces.
This creates demand-based air exchange that is independent of occupant ventilation habits.
Typical applications include:
Targeted control of airflow ensures consistent ventilation throughout the building and supports the long-term protection of the building structure.
It is only through the interaction of the individual components that a ventilation solution becomes a well-designed overall system. The modular approach makes it possible to tailor each component precisely to the requirements of the building.
The result is a solution that addresses not only technical requirements but also economic and architectural considerations. For planners, contractors, and building owners, this means greater flexibility during project implementation and the ability to adapt ventilation concepts to actual needs rather than compromising due to rigid system specifications.
In renovation projects, practical feasibility is often just as important as technical performance. Tight schedules, complex existing conditions, and coordination among multiple trades place significant demands on both planning and execution.
Modular ventilation systems can help reduce these challenges. Standardized system components, clearly defined interfaces, and flexible application options make projects easier to plan and execute efficiently.
Renovation projects are often carried out while buildings remain occupied or within tightly scheduled construction timelines. Delays directly impact subsequent trades and overall project costs.
Modular ventilation systems support more efficient implementation because many components are already coordinated and can be integrated more easily into existing construction processes. Prefabricated installation solutions and clearly defined installation conditions can reduce installation effort and accelerate execution.
This creates a noticeable time advantage, especially in projects involving multiple residential units or phased renovation schedules.
Existing buildings often present uncertainties. Undocumented building components, varying structural conditions, or changing usage requirements may make adjustments necessary during the project phase.
Modular concepts provide additional flexibility. Rather than adapting a rigid overall system to fixed conditions, the design can be tailored to the actual building situation.
For planners, this offers advantages such as:
This reduces the risk of extensive redesign work during construction.
In addition to planning and installation, long-term operation should already be considered during the concept phase. Maintenance, cleaning, and service requirements have a significant impact on the overall cost-effectiveness of a ventilation solution.
Maintenance-friendly systems are characterized by easy access to relevant components, simple filter replacement, and clearly structured system layouts.
This offers several advantages for operators:
This aspect is becoming increasingly important, particularly in residential buildings and commercially used properties.
Investment costs alone provide only a limited view of the true cost-effectiveness of a ventilation solution. What matters is the total cost over the entire service life.
Several factors play a role:
Modular ventilation systems can offer advantages here because they can adapt to changing conditions and often allow expansions without requiring a complete system replacement.
Particularly in existing buildings intended for long-term use, this results in a solution that is not only technically effective but also economically sustainable over time.
For planners, contractors, and building owners, this means greater investment security and more flexibility throughout the building’s entire lifecycle.
The requirements for modern renovation projects extend far beyond energy savings alone. Alongside an improved building envelope, issues such as moisture protection, indoor air quality, occupant comfort, and long-term cost-effectiveness are becoming increasingly important.
Modular ventilation systems offer a practical solution. Their flexible design allows them to be adapted to different building structures, renovation scopes, and technical requirements. At the same time, they support phased implementation and provide the flexibility needed for future expansions or changes in building use.
In existing buildings especially, planners, contractors, and building owners benefit from solutions that adapt to existing conditions rather than requiring extensive modifications to the building structure. Prefabricated system components, maintenance-friendly concepts, and the ability to expand according to demand support cost-effective and sustainable project execution.
Anyone who incorporates ventilation into renovation planning at an early stage lays the foundation for a permanently healthy indoor climate, protection of the building structure, and energy-efficient building operation.
Modular ventilation systems are therefore more than just a technical solution for air exchange. They are an important building block of modern renovation projects, enabling customized ventilation concepts tailored to the actual requirements of the building.
Yes. Modern ventilation systems can be retrofitted in both residential and commercial buildings. Modular solutions are particularly well suited because they can be adapted to existing building structures and can often be installed with minimal modifications to the building fabric.
Modular ventilation systems enable flexible planning and implementation. Individual components can be combined, expanded, or integrated in different construction phases as needed. This creates ventilation concepts that can be tailored to the requirements of the specific building.
New windows and improved insulation standards make buildings significantly more airtight. Natural air exchange decreases, allowing humidity, CO₂, and pollutants to remain in the building for longer periods. A planned ventilation concept ensures the necessary air exchange and helps protect the building structure.
A ventilation system with heat recovery can be particularly beneficial in energy-efficiently renovated buildings. The heat contained in the exhaust air is used to preheat incoming fresh air. This helps reduce ventilation heat losses and lower the building’s overall energy demand.
Yes. One of the key advantages of modular systems is that they can be implemented in stages and expanded as needed. This is especially beneficial for renovations that take place over multiple construction phases or where future expansions are already being considered.
Key factors include the building structure, building usage, available installation conditions, energy-efficiency requirements, and maintenance and operating costs. Early planning helps identify the most suitable solution and avoid costly modifications later on.
Modern ventilation systems are designed for reliable long-term operation. Maintenance requirements are generally limited to regular inspections and the replacement or cleaning of filters. Maintenance-friendly system concepts make these tasks even easier.
Modular ventilation systems support sustainable building technology by combining energy efficiency, indoor air quality, and long-term building value preservation. Their adaptability also allows them to be adjusted to changing usage requirements over time without requiring the entire system to be replaced.
Controlled residential ventilation makes a significant contribution to a healthy indoor climate, protection of the building structure, and improved energy efficiency. Especially in modern airtight buildings, traditional window ventilation is often no longer sufficient to reliably remove humidity, CO₂, and pollutants. Demand-based ventilation helps prevent mold growth, improve indoor air quality, and reduce energy losses at the same time.
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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.
