Condensation on the frame of new aluminium windows

[ronniecabers]

In fact their windows are generally so much better, that the problem of external condensation is more widely known and understood…

I had to think about that for a moment - how could you get external condensation!? So, I figure that this is most likely to happen early in the day, the external glazing has cooled overnight, the external air is warming up and increasing its moisture capacity, but comes into contact with the cooler glazing (which is warming more slowly than the air, and isn't being warmed from internal sources because it is more efficiently insulated).

Would that be the scenario?

excerpt from Pilkingtons

The following is an explanation by Pilkington of the phenomenon of External Condensation.

Other Information:
Condensation Explained
External Condensation
Internal Condensation
Get New Windows



Condensation on external glass surfaces

External condensation (dew) can occasionally occur on highly insulating glass units in temperate climates. Such occurrences will only happen on cloud-free nights when there is little or no wind and usually when a warm front follows a dry spell.

The combination of several factors, namely external air temperature, localised microclimate and the thermal transmittance of the glazing itself may all contribute to the formation of external condensation. As a consequence of variable temperatures and localised conditions, it is possible to experience a situation whereby both clear and ‘misted’ windows exist at the same time in the same development.

This phenomenon is influenced by the thermal insulation of the glazing. Single glazing offers poor thermal insulation therefore heat escaping from inside a room readily passes through the glass to the outside environment. Consequently, the external surface temperature of single glazing is generally higher than the‘ dew-point’ temperature of the outside air, thus prohibiting the formation of condensation on that surface.

With conventional double glazing the thermal insulation is improved, but sufficient heat still escapes through the glass so as to warm the external surface of the outermost glass, thereby precluding the formation of condensation in most circumstances.

Need help with condensation or a replacement window

In common with other low emissivity glasses, Pilkington K Glass reflects heat back into the room and as such the quantity of heat passing through the glazing is reduced. Consequently the external pane of low emissivity double glazing is not warmed by escaping heat (which instead is retained within the room) and therefore presents a colder surface to the outside environment.

In such cases, and in situations where the external glass surface temperature is lower than the ‘dew-point’ of the air, (and when weather conditions are comparable to those mentioned previously) condensation can form on the external glass surface.

However, the combination of these contributing factors is largely unpredictable and therefore it is not possible to quantify the number of occasions when external condensation will occur.

Instances of external condensation are relatively rare and in all cases it will be a transient effect. Upon any one of the climatalogical variables changing, the condensation on the glazing will usually dissipate within a short period of time in much the same way as morning dew.

I felt this was the easiest way of explaining this , by copying one of the manufacturers of the glasses information....

 

[typonaut]

Condensation is caused when water vapour comes into contact with cold surfaces and condenses to form dampness or water droplets. Air can contain varying amounts of water vapour; warm air can hold more water vapour than cold air…

Er, you haven't been reading my posts, I've already written that about five times, in various ways. I don't need the NHBC to tell me that, it's basic physics.

I think the debate here is about whether localised cooling can exist, I think we all accept that it can, and what can be done to mitigate its effects. Aron and I seem to agree that the real problem is insulation (assuming that average humidity is in a reasonable range), while others are saying that ventilation is the answer because the humidity is too high.

While I do believe that ventilation/dehumidification can be a solution where overall humidity is above a certain level, it does tend to ignore that in certain circumstances that may not be the right answer.

I can remember living in a house where there was no double glazing and no central heating – in the winter ice formed on the inside of the windows. Now, there is no doubt that the ice came from condensation, which was frozen due to the cold. But I find it hard to accept that in those circumstances that the way to cure the condensation would be better ventilation!? Surely better insulation would be the first step.

I know that the same house has central heating and uPVC double glazing now - I don't believe that they have any problem with condensation nor ice on the internal glazing.

Do you think this is due to better insulation or more ventilation?

 

[typonaut]

I felt this was the easiest way of explaining this , by copying one of the manufacturers of the glasses information....

I'm sure they know better than me, but I would have thought it more likely to happen mid morning rather than at night. Thanks for the reference anyway.

 

[ronniecabers]

may I suggest you read the info on this link

www.pgtindustries.com/about/window-condensation-causes-and-remedies

 

[AronSearle]

The issue is to do with peaks of humidity levels....can't you see that!

That is not the situation as described, it is not the issue that causes persistent condensation on poor windows.

Nor is it what anyone else here is discussing, it may be what *you* are talking about, not my fault if you keep wanting to grab the wrong end of the stick. We are not discussing condensation occurring when someone is having a bath, or boiling a kettle, but just from average humidity levels of 30-55%, at these levels of humidity good windows should not see condensation, because their internal surface temperatures should remain high enough to prevent condensation. Bad windows will see thermal bridging and localized condensation. Even at 65% humidity which is considered high, you would need surface temperatures of 13c for condensation to occur, quality windows will not allow such low surface temperatures.

When you have condensation *only* on the window frames, that is not an indication of excessive humidity.

because as I stated you are never going to get a window to offer the same thermal properties of a wall

Strawmen and ignorance, you are a hopeless caveman trying to argue about something you do not understand.

Windows don't need to offer the same thermal properties of a wall, no one is claiming they do, they just need to maintain an inner surface temperature high enough to avoid condensation, which can still be several degrees lower than the inner air temperature.

Take a look at these thermal images of high quality windows in a passive house, outside temperature of 2.5c, inside temperature of 22c, and internal surface temperatures on the window of +16.5c at the *worst* points.

At these temperatures, condensation will not form until humidity levels are over 80% (insert ! as you like to).

I'm sorry that you are used to crap windows, made to crap standards, and fitted in a crap manner (which you must be if you think anglian windows are any good).

http://www.passivhaustagung.de/Passive_House_E/window_U.htm

 

[crank39]

Yeah but Ronnie, typo and arron are interested in curing the problem, they just want to stop it condensing on the windows, the minute another surface with a temp close to that of the window appears the condensation will appear there, like behind head boards, behind wardrobes or chests of drawers

 

[ronniecabers]

The issue is to do with peaks of humidity levels....can't you see that!

That is not the situation as described, it is not the issue that causes persistent condensation on poor windows.

Nor is it what anyone else here is discussing, it may be what *you* are talking about, not my fault if you keep wanting to grab the wrong end of the stick. We are not discussing condensation occurring when someone is having a bath, or boiling a kettle, but just from average humidity levels of 30-55%, at these levels of humidity good windows should not see condensation, because their internal surface temperatures should remain high enough to prevent condensation. Bad windows will see thermal bridging and localized condensation. Even at 65% humidity, you need surface temperatures of 13c for condensation to occur, quality windows will not allow such low surface temperatures.

When you have condensation *only* on the window frames, that is not an indication of excessive humidity.

because as I stated you are never going to get a window to offer the same thermal properties of a wall

Strawmen and ignorance, you are a hopeless caveman trying to argue about something you do not understand.

Windows don't need to offer the same thermal properties of a wall, no one is claiming they do, they just need to maintain an inner surface temperature high enough to avoid condensation, which can still be several degrees lower than the inner air temperature.

Take a look at these thermal images of high quality windows in a passive house, outside temperature of 2.5c, inside temperature of 22c, and internal surface temperatures on the window of +16.5c at the *worst* points.

At these temperatures, condensation will not form until humidity levels are over 80% (insert ! as you like to).

I'm sorry that you are used to crap windows, made to crap standards, and fitted in a crap manner (which you must be if you think anglian windows are any good).

http://www.passivhaustagung.de/Passive_House_E/window_U.htm[/QUOTE]

Please read the above post with the above link......

You still haven't answered my questions.........

You still haven't answered how you would advise getting rid of Condensation?

You still haven't answered how you come to the conclusion UK manufactured windows are ' inferior '

As goes the condensation in the original post ...NO ONE except the poster knows if it is to do with excess humidity, so you have no reason to say other wise, as nor do I. I am not the one constantly saying ventilation doesn't work to only have posted that ventilation is the answer in another thread a week ago.

I have never called you ignorant or a ' caveman' and take it that you can only do name calling rather that actually explaining how to help out the OP

As for Anglian Windows...I never said I thought they were good , I was just using there name as they are one of the biggest Double Glazing Installation companies

 

[ronniecabers]

Yeah but Ronnie, typo and arron are interested in curing the problem, they just want to stop it condensing on the windows, the minute another surface with a temp close to that of the window appears the condensation will appear there, like behind head boards, behind wardrobes or chests of drawers

Thank you Crank... I am glad you can see that by removing it from the windows it will just settle elsewhere, especially if the water vapour is not removed from the building.

 

[ronniecabers]

Oh by the way Aron, yes Passivhaus are the best , but the whole house is built together to an exacting standard............

 

[crank39]

Typo has already said the ali windows are 20years old and that they are not his to replace, so............you'd think typo would then try and eliminate the cause?

Seems logical to me

 

[AronSearle]

Typo has already said the ali windows are 20years old and that they are not his to replace, so............you'd think typo would then try and eliminate the cause?

He said that he lives in a freehold, which doesn't make sense. You can replace windows under freehold, unless it is a conservation issue (can't imagine alloy windows being part of a protected building), could be he meant he is a tenant, in which case it is the landlords problem.

If the inner surface is hitting low single figures, it will be *very* difficult to maintain the required excessively (imo) low humidity, you *won't* get it from standard ventilation. You would have to leave the windows permanently ajar with a high heating load, assuming they have a lock that allows this. Or you would have to run a dehumidifier at a high setting.

Sure these are 'solutions', but the problem is not humidity, the problem is crap windows, so the real solution is to replace or modify the windows.

You still haven't answered my questions.........

They are irrelevant.

I am glad you can see that by removing it from the windows it will just settle elsewhere, especially if the water vapour is not removed from the building.

Condensation requires low surface temperatures to occur, you are either suggesting this is not true (misunderstanding of the mechanics of condensation), or you are suggesting excess humidity, which is not reasonable to assume if condensation only occurs in one specific area.

You still haven't answered how you come to the conclusion UK manufactured windows are ' inferior '

Remind me how big the UK window export market is

 

[JohnD]

Typo and Aron think that the excessive condensation is caused by using inferior non-Scandinavian windows, and that managing the humidity is a solution to be ignored.

I have old-fashioned aluminium windows with no thermal break. My windows are closed, though I ventilate well, do not drape wet washing and do not use a dehumidifier.

Do you imagine or assume that my aluminium windows suffer from excessive condensation?

 

[ronniecabers]

Right this may be a long post ..but here goes...

Starting from original post...

Hi

In the summer we had new aluminium window put in, which have a thermal break, but as the weather had turned colder we get condensation on all the window frames apart from the one in the front room.

Do we need to contact the suppliers? Or do something to prevent the condensation?

Please help, thanks

OP has new Ali windows with thermal break and has condensation all windows bar one ...... FACT
We do not know the circumstances as to why the window was replaced, and to whether or not ' excess water vapour ' is being added to the property, we also do not know how the windows were fitted....Therefore we can not ascertain whether Water Vapour levels are average or higher than average....FACT

The suggestions to alleviate the levels of water vapour have been through ventilation ( by opening window /door , dehumidifer ( which will require emptying or you'll be adding more water to the room ) , or extractor fans...Most agree with this ..Aron & Typo do not FACT

A snippet take from an article on the internet......
MOISTURE AND RELATIVE HUMIDITY

Before looking at condensation it is necessary to understand a little about water vapour in the air. At any given temperature the air can hold a given level of water as vapour - the warmer the air the greater the potential amount of water vapour that can be held. For example:
Air at 10ºC is saturated when it contains 7.6g water per kg dry air and air at 20ºC is saturated when it contains 15.3g water per kg dry air - just over double.

So if we know the maximum amount of water that can be held it is very useful to know how 'saturated' the air actually is, i.e. what is the proportion of actual water vapour in the air compared to the maximum amount that can be held at a given temperature. This proportion is known as the RELATIVE HUMIDITY (RH) and is expressed as a percentage.

Relative humidity can therefore be defined one way as the actual amount of water vapour in the air expressed as a percentage of the maximum amount of water vapour that could be held at the same temperature.

So air, say (in round figures), at 10ºC could hold 8 grams of water vapour at its maximum, but if in reality only 4 grams was actually found, then the relative humidity would be 4/8 x 100 = 50% i.e., the air is 50% saturated. Similarly air at say 20ºC could hold around 14 grams of water vapour at its maximum, but if we found only 7 grams in the air then the relative humidity would also be 7/14 x 100 = 50% at that temperature

So my quick understanding , the cooler the air in the room , the less grams of water it takes for the air to become saturated and therefore aid in Condensing on cooler surfaces...

Another snippet from the same website .....

The formation of condensation on cool surfaces in a property is caused by the 'life style' of its occupants - in other words it is how you live and what you do in your property that produces the water vapour that might eventually end up on cool surfaces as condensation.
For example:- If you get into a car on a cold morning often the windows steam up and the more people in the car the quicker this happens. To clear the windows you have to turn on the ventilation fan and heater. So why does this condensation happen? As warm blooded living breathing mammals we introduce considerable amounts of water vapour into the atmosphere just by breathing and perspiring. In the confined space of a cold closed car this water vapour will very quickly condense on cold surfaces the most visible being the inside of the windows. In other words it is you (and any other car occupants) that produced the water vapour and caused the windows to steam up - it was not the car's fault!
Although much bigger, in terms of condensation a property behaves in much the same way as a car. A property that has stood vacant for some time does not usually suffer from condensation as nobody is living in it and no water vapour is being produced. As soon as occupants move in and start cooking, bathing, breathing and perhaps worst of all drying clothes inside, each of these actions producing quantities of water vapour, there is a significantly increased risk of condensation becoming a nuisance causing mould growth and a characteristic 'musty smell'. This is more likely to happen in poorly heated and poorly insulated properties.

Ok, I'm still following ......

Right another snippet same website ........regarding


Condensation 5 - "How do we prevent condensation happening in a house?"
There are two ways the situation needs to be be approached.
Obviously we are not able to stop breathing or perspiring but we should consider all other water vapour generating activities that take place in our homes such as cooking, bathing, clothes drying etc. Large dogs and tropical fish tanks also contribute significant levels of water vapour into the atmosphere. Whenever possible the water vapour unavoidably generated by each of these activities should be forcibly extracted at source directly to the outside. By doing this the amount of water vapour suspended in the atmosphere within a property is reduced thus there is less water vapour in the atmosphere to potentially be deposited as condensation. Therefore even if the air is cooled it may still be able to support the reduced amount of water vapour. If forced extraction is not possible a correctly used good domestic dehumidifier (possibly more than one) will considerably reduce the amount of water vapour suspended in the atmosphere within a property. So if for example you dry clothes inside on radiators etc. stop doing this imediately - the result will be dramatic.
The second approach to be used in conjunction with the above is to provide constant adequate dry heat combined with good levels of insulation. Not only will a constant supply of heat increase the temperature of wall surfaces meaning the likelihood of condensation forming is reduced, but it will also increase the ability of the atmosphere to support water vapour. If wall surfaces are kept warmer by insulation then they are more likely to be above dew point temperature and the water vapour will remain suspended in the atmosphere and not be deposited as condensation

Now onto some interesting bits....
Condensation 10 - "If you fit double glazing it will cure condensation"

Nothing could be further from the truth. Often before double glazing is fitted the single glazed windows 'steamed up' or ran with water on cold mornings. After fitting new double glazed windows hey presto the condensation no longer forms on the windows - in other words it is no longer visible but has it gone away?

Well from the windows yes - but previously the single glazed windows ran with water and in so doing they acted as a dehumidifier removing water vapour from the atmosphere within the property. It is also very probable that the old single glazed windows did not fit as well and they provided a certain amount of 'involuntary ventilation'. By fitting draft free sealed unit double glazed windows the dehumidification effect of the single glazed windows is removed and the 'involuntary ventilation' prevented.

If the life style of the occupants remains unchanged then a proportion of the water vapour that previously formed on the windows or escaped in draughts will very likely form elsewhere. It is not unusual for mould growth to form in corners on walls as a result of condensation after double glazing has been installed.

So does double glazing cure condensation? No it does not - it just shifts it elsewhere.

and a bit more info.....

Condensation 11 - "They say ventilation will cure condensation"

Water vapour exerts a pressure and areas of high vapour pressure (such as inside our homes) will always seek to equilibrate vapour pressure by moving to areas of lower vapour pressure (outside) and ventilation provides an 'easy' escape for this to happen. However not only does water vapour escape but also heat. The warm moist air is replaced by dryer cooler air which is good but some have suggested this reduces wall surface temperatures leaving them more susceptible to condensation. The cool replacement air also has to be heated to maintain comfort levels within the property and this costs money.
There is no doubt that controlled ventilation will contribute towards the reduction of a condensation problem and create a healthier environment but it probably will not be the complete cure. Other control measures are likely to be necessary and a complete cure lies with the life style activities of the occupants.

Right I'm going to stop copy and pasting now, but that paricular website and many more pretty much say the same thing....

A couple of other little things..Typo , you stated I did not understand condensation, then when I posted how it is formed , you agreed with me ...so either I do understand it and you were ignoring that fact for arguements sake, or I don't understand it and neither do you.....

Aron....more questions for you I am afraid, and I would be very honoured if you could humour me with some responses, rather than dismissing them as irrelevant, no question I have asked has been irrelevant in my eyes, I am just an enquistive person, I would be very greatful....

1/ I have visible water vapour in the form of steam, I put on the extractor fan, the visible water vapour disappears ...why?
2/ Non condensing tumble driers have pipes to carry the air outside....why?
3/Modern Uk windows are inferior, do you have proof of this?
4/ Norwegians don't suffer Condensation ...Do you have proof of this?
5/ How would you deal with condensation? ( oh and I won't mention that a week ago on another post you said ventilation....oops I just have.... )

Just another little piece of info , I think is relevant, ....


Water vapour source in an
'average' house per day

4/5 people asleep 1.5 Litres of water generated approx
2 people active 1.6 Ltrs of water generated approx
Cooking 2.6 ltrs of water generated approx
Washing up 1.0 ltrs of water generated approx
Washing clothes 4.0 ltrs of water generated approx
Drying clothes 4.5 ltrs of water generated approx
Bathing/washing 0.5 ltrs of water generated approx

Approximate total 15.7 litres

I thought this bit was worth sharing from that website again, oh and by the way , before you try and dismiss copy and pastes from the website , they come from Building Preservation Consultant , and I think they will understand the issues more than me....and you

I would very much appreciate your thoughts on this ( and answers to my questions ).....

 

[ronniecabers]

Oh Aron , I forgot to say , just because our export figures for Upvc windows aren't very high in the UK, doesn't mean they are ' inferior ' ....not a particularly ' scientific ' measure is it?

 

[ronniecabers]

Windows don't need to offer the same thermal properties of a wall, no one is claiming they do, they just need to maintain an inner surface temperature high enough to avoid condensation, which can still be several degrees lower than the inner air temperature.

Can I ask then , what is your solution to bring up the internal temperature of the Frame and glass to alleviate Condensation?