Condensation on double glazing

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I had some double glazing fitted last year, it was fitted by a FENSA registered company, but was the cheapest quote we found - approx 4000 for 6 leaded windows and a patio door.
We are happy with the windows etc, but in winter sometimes get condensation on the windows. This only happens on mornings where it is particually cold and wet out, it burns off by midday, and is worse in rooms where people have been sleeping.
The water is not inbetween the pannels (as I can wipe it off) and the panels dont feel particually cold.
The links below are some pictures of the condensation, I just wanted to know if it is a result of buying cheap double glazing (in which case fair enough) or if it means they are faulty. Is there some kind of measureable leagal minimum that the windows need to comply with?
http://www.websphereusergroup.org.uk/temp/IMGP1572.JPG
http://www.websphereusergroup.org.uk/temp/IMGP1573.JPG
http://www.websphereusergroup.org.uk/temp/IMGP1574.JPG
Thanks
David Bevan http://www.davidbevan.co.uk
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snipped-for-privacy@davidbevan.co.uk wrote:

It's the result of having inadequate ventilation in the room, that's all. Windows will always be the coldest spot in the room, and that's where water vapour will condense.
How is the room ventilated?
--
Grunff

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In uk.d-i-y snipped-for-privacy@davidbevan.co.uk wrote:

Condensation can happen on double glazed windows. It'll be much less than the equivalent on single glazed.
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snipped-for-privacy@davidbevan.co.uk explained :

The problem would seem to be lack of or poorly thought out ventilation and/or heating, rather than any fault in the windows.
The better sealed your home is, the more thought needs to be put into its heating and ventilation. Radiators are normally location under windows to keep a warm flow of air rising over the glass. If you don't already have them...
1. Install a cooker hood which discharges the moist air from cooking outside, rather than a simple filter type.
2. Install an adequate and preferably automatic bathroom fan.
3. Install a utility room fan and use it when ever the washer/drier is in use.
Cavity wall insulation will also help prevent in a small way - moisture being absorbed by the walls to be released later in the day.
--

Regards,
Harry (M1BYT) (L)
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explained :

On the contrary - we found that we had MORE condensation on dg windows after our cavities were insulated - donkey's years ago. The walls were then warmer than the glass so the condensation appeared on the glass.
It proved that the cavity insulation was working!
Mary

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It happens that Mary Fisher formulated :

Hi Mary...
That was not our experience, though I suppose it depends how much moisture is absorbed into the cold walls. The DG was installed first and we initially had similar problems to the OP. I then added ventilation followed some years later by the CWI.
Our internal atmosphere is now so dry, that we have had to resort to adding water evaporation trays to the tops of radiators to increase the humidity in winter.
--

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Harry (M1BYT) (L)
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Glass is not made equal, there is a rating CDF or condensing factor which few know about. An old Consumers Reports window test of apx 28 windows showed how they vary. Pella lowEargon do much worse than Anderson lowEargon on CDF. My Pellas condense my Anderson dont. You say you bought cheap, you got what you wanted, cheap.
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Double glazing doesn't prevent condensation but merely reduces it. People in a room produce water vapour from their breath, and this tends to condense out on the coldest part of the room which will still be the window. You need either more ventilation or stopping the temperature dropping so low inside to prevent it.
--
*The most wasted day of all is one in which we have not laughed.*

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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The surface temperature of the inside pane of glass is colder than the dew point of the air in the room. Either you are running a humidifier with too high a setting or you bought cheap glass, which is the most likely answer. I just replaced my widows 2 years ago. The company had a good reputation and was not the most expensive, but I got the most expensive windows they had. It was worth the money. Note, the colder it is outside, the more likely it is the condensation will occur, as it makes the glass colder. Moisture levels outside will have less impact than temperature outside.
Stretch
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snipped-for-privacy@davidbevan.co.uk wrote:

Nice looking windows. As the others have pointed out your new windows can only reduce the condensation. I have three suggestions that were not noted to add.
1. If you have window coverings drawn at night it will increase the problem. It blocked the cold air up next to the window allowing the window to cool even more. As soon as the windows gets below the dew point for the room then condensation will take place. The window coverings will reduce heating expense but also increase condensation.
2. Your bed rooms are prime for this kind of problem because they are often a little more moist at night due to people breathing and adding moisture to the air.
3. Condensation results whenever the humidity in the room goes above the dew point of the cold object. Things like curtains reduce air flow, but moisture goes right through them.
--
Joseph Meehan

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Joseph Meehan wrote:

I forgot one thing. When they put in new windows, they likely tightened up the home as well so it is not exchanging as much air so the humidity inside has more of a chance to build up as it did before and that tends to raise the dew point.
--
Joseph Meehan

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As others have said..it's due to a lack of ventilation. Replacing old windows with double glazing can sometimes make condensation worse because it eliminates ventilation through the badly fitting old windows.
When people breath they put water vapour into the air. The amount of water vapour that the air can hold depends on the temperature. If the temperature drops - for example when the damp air comes into contact with cold glass the excess can condense out (=rain).
There are two main solutions....
1) Add ventilation (open windows or trickle vents) to let the damp air out and dry air in (outside air is normally dryer even in winter).
2) Use a dehumidifier to remove the water vapour from the air.
Personally I feel the only "perfect" solution is to install whole house ventilation system with heat recovery. Think of it like opening a windows without loosing the heat.
http://www.toolbase.org/techinv/techDetails.aspx?technologyID 2
http://www.villavent.co.uk/domestic-ventilation-systems.htm
Note that UK Building Regulations require replacement windows to meet the Building Regulations. This can include the need for them to have built in trickle vents (if the house doesn't have a ventilation system). If your new windows have trickle vents in the frames make sure they are open - that might be sufficient but I suspect not as they are frequently a bit on the small side.
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snipped-for-privacy@davidbevan.co.uk wrote:
here's whats happening
that side of the house is the coolest
that's all
the rest of the winders are progressively less moisturous being closer to the warmer side of the house
off topic: that's a nice camera!
you know a HD movie is only 720x480 or somewhere therebouts.
can you imagine a movie where each frame is the of the poster you posted
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snipped-for-privacy@davidbevan.co.uk wrote:
here's whats happening
that side of the house is the coolest
that's all
the rest of the winders are progressively less moisturous being closer to the warmer side of the house
off topic: that's a nice camera!
you know a HD movie is only 720x480 or somewhere therebouts.
can you imagine a movie where each frame is the of the poster you posted
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snipped-for-privacy@davidbevan.co.uk wrote:

I had the same thing with my patio door, a metal-framed one installed circa 30 years ago. Moisture would condense on the frame, and on the lower part of the glass, eventually leaving small patches of mould on some of the hardwood frame. It took me a little while to work out what was happening. The pictures you took show exactly the problem here.
I traced the problem to a 'reverse chimney' effect due to the curtains being closed. There was circa a 1" gap between the top of the curtains and the ceiling, and similar one at the bottom.
As air trapped by the curtains cooled, it sank and emerged into the dining area, to be replaced by warm moist air at the top. There comes a point somewhere near but not at the bottom of the glass where the temperature falls below the dew-point, and moisture condenses out. The pattern of condensation is exactly as depicted in your photos. This continues ad infinitum, drawing moisture from the room and depositing it on the glass and frame. The colder the night, the farther up the glass the condensation started.
Putting 'sammy snakes' (draught excluders) along the bottom of the curtains stopped the problem completely. Although cutting off the flow of air made the glass colder, the very limited airflow meant that condensed vapour could not be replaced, and the problem has gone away. The dining area is also a lot warmer!
I put a wireless thermometer between the curtains and the glass. With no draught excluder in place, the temperature drop from ambient was about 5 degC or so. With the sammy snakes in place, the thermometer read just above the outside temperature, a drop on the night in question of over 20 degC.
My suggestions: make sure that obvious sources of dampness are removed from the rooms concerned (towels, clothing, large plants, etc) and cut the air-flow off with draught-excluders. Your window-cills look ideal for this. It may take a day or two for your rooms to reach any new humidity equilibrium. HTH
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Condensation is NORMAL
On 18 Feb 2006 01:38:37 -0800, snipped-for-privacy@davidbevan.co.uk wrote:

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snipped-for-privacy@davidbevan.co.uk wrote in

Surprised no one has asked (or I missed it) if you have exhaust fans in the shower(s) and using them with the door closed. Or if person(s) tend to exit and leave door open shortly after shower. Better to leave fan on after exiting and close door until at least the mirror clears. May not have made a difference before but does now.
Just one of many possible contributors but a significant one.

Are there other types in the UK? :-)
"websphere" <- don't see many of those users in the general population.
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Except that the fan uses power, an open door doesn't.
Mary
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Mary Fisher wrote:

A fan uses very little power, and provides a huge improvement in the air quality. An open door uses no power but simply moves the moisture from one place to another - hardly a solution.
--
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The poster was complaining about condensation on windows. Opening a door, in my experience, solves the problem.
Mary

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