Hello dear forum,
We are using a Zehnder ComfoAir Q350. Unfortunately, it has had some issues with the "installation" from the start. First, the wrong settings were applied, and then the interior doors were too airtight. After the ventilation technician visited about five times since summer, it is now running reasonably well. Although the air quality in the bedroom still feels as if we have no ventilation, according to the technician everything is set up correctly.
Now that the weather has turned quite cold recently, we have noticed significant condensation on the windows in some areas. Especially in the bedroom and also in the open living-dining area. The technician said this is normal in a new building – however, due to the ventilation system and underfloor heating, we only have about 25% humidity. With an additional humidifier (Venta), we manage to reach almost 40%.
Question: Shouldn’t a ventilation system automatically remove moisture inside the house and prevent the windows from fogging? Is it possible that the ventilation system is still not correctly adjusted? How can something like this be tested?
Information about the picture:
- Bedroom (16 m² (172 sq ft))
- Room temperature approx. 18-19°C (64-66°F)
- Two adults and occasionally a toddler (2.5 years)
- 1x supply air (Zehnder)
Thank you very much!
Bastian
We are using a Zehnder ComfoAir Q350. Unfortunately, it has had some issues with the "installation" from the start. First, the wrong settings were applied, and then the interior doors were too airtight. After the ventilation technician visited about five times since summer, it is now running reasonably well. Although the air quality in the bedroom still feels as if we have no ventilation, according to the technician everything is set up correctly.
Now that the weather has turned quite cold recently, we have noticed significant condensation on the windows in some areas. Especially in the bedroom and also in the open living-dining area. The technician said this is normal in a new building – however, due to the ventilation system and underfloor heating, we only have about 25% humidity. With an additional humidifier (Venta), we manage to reach almost 40%.
Question: Shouldn’t a ventilation system automatically remove moisture inside the house and prevent the windows from fogging? Is it possible that the ventilation system is still not correctly adjusted? How can something like this be tested?
Information about the picture:
- Bedroom (16 m² (172 sq ft))
- Room temperature approx. 18-19°C (64-66°F)
- Two adults and occasionally a toddler (2.5 years)
- 1x supply air (Zehnder)
Thank you very much!
Bastian
The function apparently shuts down the system or reduces its output when it gets too cold:
According to the manual:
Frost Disbalance – displays the current status of the airflow imbalance caused by the frost protection function. The percentage of supply air reduction is shown.
According to the manual:
Frost Disbalance – displays the current status of the airflow imbalance caused by the frost protection function. The percentage of supply air reduction is shown.
B
baschdieh22 Jan 2019 10:39ares83 schrieb:
The function apparently shuts down the system or reduces its output when it gets too cold:
According to the manual:
Frost Disbalance – displays the current status of the airflow imbalance caused by the frost protection function. The percentage of supply air reduction is shown.The display only shows this message – I just checked under "Status" – it indicates it’s at 5%, but that probably isn’t the real problem.
M
Mottenhausen22 Jan 2019 11:39Don’t overcomplicate it: you’re adding extra moisture to the air:
But you expect the mechanical ventilation with heat recovery to quickly vent out this added moisture before it condenses on surfaces where the dew point is undershot? A local electronic room humidifier controls very… digitally: if it measures too low, it briefly raises humidity to 60%+ in the immediate area and expects that it will mix down to 40% throughout the whole room. In practice, that doesn’t work: the humidifier’s “cloud” moves along the natural air circulation toward the ceiling and then falls back down along the windows, where it can easily condense.
How warm are the rooms at night where condensation occurs? If you definitely want to maintain 40% humidity, you also need to ensure the necessary room temperature is maintained, around 22°C (72°F) or higher continuously.
baschdieh schrieb:
With an additional humidifier (Venta), we reach just under 40%.
But you expect the mechanical ventilation with heat recovery to quickly vent out this added moisture before it condenses on surfaces where the dew point is undershot? A local electronic room humidifier controls very… digitally: if it measures too low, it briefly raises humidity to 60%+ in the immediate area and expects that it will mix down to 40% throughout the whole room. In practice, that doesn’t work: the humidifier’s “cloud” moves along the natural air circulation toward the ceiling and then falls back down along the windows, where it can easily condense.
How warm are the rooms at night where condensation occurs? If you definitely want to maintain 40% humidity, you also need to ensure the necessary room temperature is maintained, around 22°C (72°F) or higher continuously.
B
baschdieh22 Jan 2019 11:48Mottenhausen schrieb:
Don’t overcomplicate it: you are adding moisture to the air, but expect the mechanical ventilation system to quickly remove this added humidity before it condenses on surfaces where the dew point is undershot? A local electronic humidifier controls very... digitally. If it measures too low, it temporarily increases humidity to over 60%+ in its immediate vicinity, expecting it to mix down to about 40% in the whole room. In practice, this doesn’t work: the humidifier’s moisture cloud moves along the natural air circulation toward the ceiling and then falls down along the windows, where condensation can nicely form.
How warm are the rooms experiencing condensation at night? If you really want to keep the 40% relative humidity, you also need to ensure the necessary room temperature is maintained—so at least 22°C (72°F) around the clock.The Venta only runs in the open living area—here the temperature is 22°C (72°F). In the bedroom, where we have the condensation problem, nothing runs.
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