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
N
nordanney25 Jan 2019 12:06baschdieh schrieb:
So, the glass is freezing cold at the bottom – significantly colder than the room temperature. So the glass or the window is the problem? Yes, that shouldn’t happen. Even if the humidity is low, it will have no choice but to condense on the window.
apokolok schrieb:
If you don’t have a suitable thermometer, just do it manually.
As a reference, you can use objects with known temperature ranges, for example, fridge, basement, bedroom. This only works if the objects are made from similar materials. Hands don’t measure temperature but heat flow (?). I’m not entirely sure what exactly, but it’s definitely not temperature. When trying to estimate temperature by touch, you quickly end up with very inaccurate results.
However, it makes sense here to compare the suspicious window with other windows.
Kekse schrieb:
This is only possible if the objects are made of similar materials. Hands don’t measure temperature but heat flow (? I’m not entirely sure what exactly, but definitely not temperature)Hands can compare relative temperatures of the same materials (or materials with the same thermal conductivity). That means comparing one pane with another is fine, but comparing a pane with a piece of metal is not.
This is also why a wooden floor is generally perceived as "warmer" than tiles. The surface temperature of both materials is the same at the same room temperature.
Kekse schrieb:
? That is basically exactly what I am saying, isn’t it? Except that I wouldn’t leave out the heat capacity if I were to start with thermal conductivity Yes, that was poorly phrased, I just wanted to clarify it a bit in case someone wants to look it up later.
D
Dark_Templar2 Feb 2019 14:24baschdieh schrieb:
So the ventilation system is probably the culprit. I found out that the unit apparently stops supplying fresh air from around 4:00 PM. On the Zehnder display, it shows “Frost Disbalance” – in the status, I saw that the “frost protection” was set to 100%, and the fresh air supply was at 0%. In the evening, I left the bedroom door open, and as a result, the windows stayed dry.
After some research, I have now found out that I apparently need a preheating coil for the system to operate properly in below-freezing temperatures. Can you confirm this?For heaven’s sake, install an enthalpy exchanger instead; this will improve humidity control and the system will run properly except in extreme cold conditions.
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