Hello, we have a huge problem.
We have been living in a new KfW 55 house since early summer, and now there is significant condensation on the lower part of all the windows, both on the glass and the frame, with damp joints/corners on the windowsill (unfortunately made of wood -> mold). Room temperature about 23°C (73°F), relative humidity around 55%, decentralized ventilation system. The blower door test was good, so everything is airtight. The installation looked professional to me; in the timber frame house, everything fits very precisely, with sealing using self-expanding foam rubber tape, and polystyrene insulation wedges below the window.
The architect and window fitter are coming on Monday. But maybe someone from the forum can already offer advice or has had similar experiences. I believe that in new buildings with new windows, this should not happen.
Unilux plastic windows, "ISO STAR"
Profile depth 88 mm (3.5 inches) with six profile chambers, outer frame 76 mm (3 inches), sash 78 mm (3 inches)
ISO thermal insulation glazing Ug 0.5 – Glass construction: ISO 4-18-4b-18-4, 26 mm (1 inch)
Warm edge spacer
Thermal transmittance value 0.76 W/m²K
We have been living in a new KfW 55 house since early summer, and now there is significant condensation on the lower part of all the windows, both on the glass and the frame, with damp joints/corners on the windowsill (unfortunately made of wood -> mold). Room temperature about 23°C (73°F), relative humidity around 55%, decentralized ventilation system. The blower door test was good, so everything is airtight. The installation looked professional to me; in the timber frame house, everything fits very precisely, with sealing using self-expanding foam rubber tape, and polystyrene insulation wedges below the window.
The architect and window fitter are coming on Monday. But maybe someone from the forum can already offer advice or has had similar experiences. I believe that in new buildings with new windows, this should not happen.
Unilux plastic windows, "ISO STAR"
Profile depth 88 mm (3.5 inches) with six profile chambers, outer frame 76 mm (3 inches), sash 78 mm (3 inches)
ISO thermal insulation glazing Ug 0.5 – Glass construction: ISO 4-18-4b-18-4, 26 mm (1 inch)
Warm edge spacer
Thermal transmittance value 0.76 W/m²K
U
Username_wahl13 Jan 2017 19:41Hello, the window company and UNILUX deny everything. Apparently, there are too many plants and two aquariums in the house, which they say is causing the high indoor humidity. The architect thinks the window frames might be poorly insulated. In any case, during the cold period, the window surfaces were at least 5°C (9°F) colder than the room center, and the relative humidity near the windows was above 80%. It’s no surprise that condensation formed. We have been ventilating thoroughly through the windows for several days now, and the relative humidity is currently below 50%, with no condensation at the moment. I hope it gets really cold outside again so we can see if the problem reoccurs.
We also have the Isostar windows and about 55% humidity, so that alone can’t be the cause. In fact, during winter, I sometimes place bowls of water around because the air gets too dry when heating. A humidity level of 25% is harmful to health and cannot be considered a healthy indoor climate. How much lower should the humidity be reduced?
Our windows also fog up, but only on the outside. The inner pane always feels "warm" to the touch—try placing your hand on it. Even in the basement, where we have 15°C (59°F) and 55% humidity, there is never any condensation.
By the way, we only ventilate once a day.
Our windows also fog up, but only on the outside. The inner pane always feels "warm" to the touch—try placing your hand on it. Even in the basement, where we have 15°C (59°F) and 55% humidity, there is never any condensation.
By the way, we only ventilate once a day.
U
Username_wahl5 Oct 2017 23:04Not yet. I am eagerly awaiting the next winter.
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