J
JonnYWeeD7 Feb 2012 16:17Hello everyone,
I’m having the usual problem this time of year with a lot of condensation forming on the lower and side edges of the roof window.
Outside temperature is about -15°C (5°F), inside about 22°C (72°F) with 43% humidity. The house was completed two years ago. The window reveal is designed to allow warm air to flow upward along the window. The heat comes from underfloor heating. We ventilate about 4 times a day for around 5 minutes each time, opening windows diagonally. Sometimes only 3 minutes during such cold weather. The humidity then drops to about 33%, almost too low. Still, condensation forms on the glass in the evening and then overnight.
Does anyone have any ideas on how to prevent this? Besides ventilating a lot—which we do and I believe do correctly.
Is there a foil or film that can raise the surface temperature of the glass?
Could the roof windows be defective? They have been installed for two years with insulation frames. But this problem occurs with all the windows, so it would be strange if they were all faulty. Roto sent me new seals which didn’t help either.
I would appreciate any responses.
Best regards,
JonnY
I’m having the usual problem this time of year with a lot of condensation forming on the lower and side edges of the roof window.
Outside temperature is about -15°C (5°F), inside about 22°C (72°F) with 43% humidity. The house was completed two years ago. The window reveal is designed to allow warm air to flow upward along the window. The heat comes from underfloor heating. We ventilate about 4 times a day for around 5 minutes each time, opening windows diagonally. Sometimes only 3 minutes during such cold weather. The humidity then drops to about 33%, almost too low. Still, condensation forms on the glass in the evening and then overnight.
Does anyone have any ideas on how to prevent this? Besides ventilating a lot—which we do and I believe do correctly.
Is there a foil or film that can raise the surface temperature of the glass?
Could the roof windows be defective? They have been installed for two years with insulation frames. But this problem occurs with all the windows, so it would be strange if they were all faulty. Roto sent me new seals which didn’t help either.
I would appreciate any responses.
Best regards,
JonnY
I have the same problem.
Built in 2009, underfloor heating.
The rooms are ventilated 3-5 times daily for 3-10 minutes each time.
In the mornings and evenings, the windows are wiped dry with a cloth.
I even have ice forming on the inside of the windows.
The condensation has already caused stains on the wall.
I am considering commissioning a building inspection report for this.
Do you have any advice or experience?
Is this normal and acceptable?
Regards,
Dan
Built in 2009, underfloor heating.
The rooms are ventilated 3-5 times daily for 3-10 minutes each time.
In the mornings and evenings, the windows are wiped dry with a cloth.
I even have ice forming on the inside of the windows.
The condensation has already caused stains on the wall.
I am considering commissioning a building inspection report for this.
Do you have any advice or experience?
Is this normal and acceptable?
Regards,
Dan
S
Stadtvilla-201211 Feb 2012 11:36We currently have the same problem in our rental apartment. Especially at -10 degrees Celsius (14°F) outside, the windows are dripping with water. The only solution is ventilation, ventilation, ventilation. You only need to leave the window tilted open for 2 hours, and the water disappears. Of course, this results in significant heat loss. I don’t understand why houses are built so airtight and then not equipped with a ventilation system – it’s practically impossible to ventilate 3-4 times a day, at least for working people. In addition, this unnecessary ventilation (compared to a less airtight house) wastes heating energy, which then has to be reinvested to bring the room back up to 20 degrees Celsius (68°F). I can hardly imagine that this results in any energy savings.
Yesterday, I attended a lecture on the topic of passive houses at a trade fair. Quote: “Back then, critics mocked that passive house residents would drown in condensation water. So far, no one has drowned.” I would have liked to add: “Maybe not drowned, but they’ve definitely had wet feet.”
Hopefully, we won’t have this problem – we are building with controlled mechanical ventilation with heat recovery.
Yesterday, I attended a lecture on the topic of passive houses at a trade fair. Quote: “Back then, critics mocked that passive house residents would drown in condensation water. So far, no one has drowned.” I would have liked to add: “Maybe not drowned, but they’ve definitely had wet feet.”
Hopefully, we won’t have this problem – we are building with controlled mechanical ventilation with heat recovery.
Hello,
This is a very typical case of a local thermal bridge => the windowpane!
While exterior walls and roof constructions in new buildings are increasingly designed with better U-values, the window frames often remain at an outdated development level, meaning the U-value of the window sash (pane) is much lower than that of the adjacent roof surfaces. The air "finds" the weakest point in the entire building structure to condense, which in this case is the windowpane. This is a defect for which the designer is responsible. It cannot be fixed by excessive ventilation, which would also lead to excessive heating energy consumption.
Best regards.
danair schrieb:
...I’m considering whether to commission a building inspection report for this. Do you have any advice or experience? Is this normal and acceptable?
This is a very typical case of a local thermal bridge => the windowpane!
While exterior walls and roof constructions in new buildings are increasingly designed with better U-values, the window frames often remain at an outdated development level, meaning the U-value of the window sash (pane) is much lower than that of the adjacent roof surfaces. The air "finds" the weakest point in the entire building structure to condense, which in this case is the windowpane. This is a defect for which the designer is responsible. It cannot be fixed by excessive ventilation, which would also lead to excessive heating energy consumption.
Best regards.
B
Bauexperte11 Feb 2012 13:38Hello €uro,
Yep, you were faster than me
Supplement:
@danair
Before you hire an expert, check your contract. I’m sure you purchased the double casement windows exactly as they were installed
Kind regards
€uro schrieb:
A defect for which the planner is responsible.
Yep, you were faster than me
Supplement:
@danair
Before you hire an expert, check your contract. I’m sure you purchased the double casement windows exactly as they were installed
Kind regards
J
JonnYWeeD14 Feb 2012 09:43Good morning,
That’s easy to say. I built two years ago, so the windows were ordered about 2.5 years ago. The standard windows and doors are triple-glazed. The roof windows are not; back then they weren’t even available yet. Roto only brought these roof windows to market in early 2011. My insulation is 22mm (0.9 inch) with 0.8; there is no window (frame) on the market that fully achieves these values. My roof windows have 1.2, and that was the best available at the time.
I still believe the problem lies with the window seals. Round seals are not cut at miters but simply glued together, which means cold air always comes in at the corners.
Of course, the best solution is to have a radiator under the window, like our parents did when building their houses. But that is difficult with a flow temperature of 32°C (90°F) at -20°C (-4°F) outside; underfloor heating is the only option then.
Well, maybe someone else has an idea...
€uro schrieb:
Hello,
A very typical case of a local thermal bridge => ... A defect for which the planner is responsible. This cannot be fixed by excessive ventilation...
That’s easy to say. I built two years ago, so the windows were ordered about 2.5 years ago. The standard windows and doors are triple-glazed. The roof windows are not; back then they weren’t even available yet. Roto only brought these roof windows to market in early 2011. My insulation is 22mm (0.9 inch) with 0.8; there is no window (frame) on the market that fully achieves these values. My roof windows have 1.2, and that was the best available at the time.
I don’t understand why houses need to be made so airtight and then not equipped with a ventilation system—it’s practically impossible to ventilate 3 to 4 times a day.Because I didn’t want a house full of dust. I have serviced ventilation systems and know what lives in the ducts after 2 to 3 years. Apart from that, I have indoor humidity of 33%. That is actually too low, yet moisture still settles.
I still believe the problem lies with the window seals. Round seals are not cut at miters but simply glued together, which means cold air always comes in at the corners.
You just have to tilt the window open for 2 hours, then the water will disappearThat is very dangerous! This cools the masonry in the window reveal, and moisture then settles in these areas. That’s where mold can spread easily.
Of course, the best solution is to have a radiator under the window, like our parents did when building their houses. But that is difficult with a flow temperature of 32°C (90°F) at -20°C (-4°F) outside; underfloor heating is the only option then.
Well, maybe someone else has an idea...
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