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Back to Knowledge Hub05.05.2026
High humidity despite ventilation is a common problem in residential spaces and on construction sites. Many assume that regularly opening windows automatically ensures a balanced indoor climate. In practice, however, the opposite is often the case: the humidity in the house remains too high or even continues to rise.
The result is fogged-up windows, musty odors and, in the worst case, mold growth. It becomes particularly critical when the relative humidity exceeds 60 percent and does not decrease over time.
The key point: in many cases, the cause is not ventilation itself, but a lack of air exchange within the building system. This is exactly where the right measures come into play.
High humidity despite ventilation occurs when moist air is not effectively removed or when new moisture is constantly being generated.
Typical causes:
In practice, only relative humidity is often considered. This indicates how much moisture the air contains in relation to the maximum possible amount.
Key principle: warm air can hold more moisture than cold air
This means:
Typical effect:
Many buildings today have a structural issue: natural air circulation is no longer sufficient.
Typical reasons:
This leads to:
Particularly critical in:
Manual ventilation is often no longer sufficient to control indoor humidity long term.
Excessive humidity is often only noticed once problems occur. However, there are clear guideline values.
General guideline:
If humidity remains above 60% over time, risks increase:
At around 70%: condensation forms on cold surfaces
Important: duration matters more than short peaks
Signs of high humidity:
These indicate:
Humidity is already too high, regardless of ventilation frequency.
Humidity problems are usually caused by multiple factors combined.
Common mistakes:
Problem:
Typical in summer:
Result:
Rooms become more humid instead of drier.
Main sources:
Fact:
a household can release several liters of moisture dailyStructural Problems
Examples:
Especially in older buildings: moisture cannot escape properly
Typical rooms:
Basement:
Bedroom:
Bathroom:
Key issue:
Result:
Humidity is only reduced temporarily, not permanently.
Correct diagnosis is essential.
Result:
Problem persists.
Important: no tilt ventilation
Important: Without a ventilation concept, problems may worsen.
If:
Then:
→ lack of continuous air exchange
Result:
They provide:
Key advantage: independent of user behavior
Suitable for:
Advantages:
Suitable for: permanent humidity
Advantages:
Rule:
The more constant the issue, the more important continuous ventilation becomes.
High humidity despite ventilation is not a ventilation problem, but a system problem.
If humidity remains high despite ventilation, a technical solution is required.
Decentralized ventilation systems ensure:
Contact
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.
