Now that the temperature outside has dropped, the windows start to accumulate water vapor. I am assuming that it might also lead to that black stuff forming. Is there a more efficient way of dealing with the condensate than wiping it dry every day?
Now that the temperature outside has dropped, the windows start to accumulate water vapor. I am assuming that it might also lead to that black stuff forming. Is there a more efficient way of dealing with the condensate than wiping it dry every day?
Couldn’t solve this as well so far. Looking at it with a thermal camera in cold weather revealed insufficiently insulated windows as the root cause. Basically the frame holding the glass sandwich itself is thermally too conductive at the seam, which tends to be a lot colder than the rest. If the difference is too low, condensations forms depending on the current dew point in your room. As a rule of thumb, if you have 22°C inside and 59% relative humidity, you have a dew point of around 14°C. If your insulation on the windows gets below that, humidity condensates there first. Airing out the room can help lower the dew point, but usually that’s barely enough.
The only fixes to lower the dew point are reducing relative humidity to inhumane levels (below 30% relative) or increasing the room temperature by alot (more than 25°C), all combined with several airing out of the room for 5 minutes 3x daily all winter.
Other things to do are identifying and monitoring high-humidity rooms nearby. Most likely your bath with a shower inside. If you have a “dark bathroom”, meaning now windows and just a vent, switch the vent for a humidity-controlled version and dial it in on around 63% humidity. Install a vent in the door near the bottom as well if not existent already, since a closed door chokes the vent. Once the door opens, water vapor enters the flat/house and raises the humidity quickly.
The only ultimate solution to this is replacing the entire windows with three-panel versions in properly insulated frames, reducing constant water vapor sources like in baths and kitchens using whatever venting methods work best there and lastly (most likely impossible due to cost if you are not considering building a new house) switch from traditional radiation heaters to an air conditioning heating/cooling solution which levels out most of the humidity issues electrically.
This is a detailed answer with which I largely agree, I just want to point out that the installation of better insulated windows shifts the problem in insufficiently insulated buildings to other areas, often the moisture then settles in corners and leads to mould there - in the past it was said that the window should always be the coldest surface in the room, today there are Ventilation, insulation,… but i think this is still a good rule
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Interesting idea. The thermo cam shows a consistent stripe of cool area where the seal sits all around the window. Not sure…
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Ah, my bad. I meant the silicone sealant of the glass pane where it meets the frame. The regular seal - while originally bad - has been fixed already. So it’s really the seal where the glass pane meets the movable window frame, not where the movable frame meets the frame fixed to the walls, if that makes sense.
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A picture should explain this better. Middle of the pane is difficult to measure in Infrared, but a regular probe taped to it shows about 18°C right now, so just a bit below room temperature. I assumed this behaviour is normal, since all windows in my rental are like this. Note that this windows specifically has not been resealed at the movable part of the frame yet. However, as you can see, it’s not the coldest point of the entire window either. Outside temperature was -3°C when the photo was taken.
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Thanks for the feedback! So, bad windows in my case. Either way, badly insulated windows just tend to form condensation it seems.
I guess in the end it’s the usual: Regular short cross-venting and wiping off moisture - or go on an insane money spending spree on insulation and air conditioning.
Thank you so much for a quality answer!