The following images are from a householder who has recently had A Rated Windows installed.
The glass combination is low iron glass, soft coat, argon gas and warm edge spacer. As you can see there is condensation (moisture) appearing on the outer pane of glass, which has started appearing on cold mornings, and clears up within a couple of hours.
The windows previously did not get any moisture appearing externally, when Low E glass was installed.
It says to me that the units are working so effectively that warm air from the inside of a house, is not getting to the outer pane. In other words, the windows are performing extremely well at cutting out heat loss.
But, how does an installation company deal with customers who find this ‘feature’ unacceptable?
On a positive note, the householder has noticed a noticeable difference to the temperature of the home, and a massive difference to the amount of natural light in their rooms.
Tags: A Rated Windows, condensation outside of glass, steamy windows
Use Werbar. You can get an A-Rating without using low iron glass. Problem sorted.
I’ve had exactly the same issues down here but it has happened with normal Low “E” glass. There is no real solution we are not allowed to fit any other glass or we will be contravening Doc L and also the customer will have higher fuel bills too.
Perhaps we have to design automatic window wipers like we have on cars, if we fitted a spray jet onto them too they could work very similarly too the cars…
Maybe the unit has been made with the low e on the wrong face and then the unit was fitted the wrong way? It’s happened before.
Andrew – sounds to me like a bigger winner for Dan at Window Widgets is to patent your window wipers idea – classic!
Jordan – glass is definitely fitted the correct way around. There’s stickers on the glass telling fitters which way to fit, so it’s unlikely a sealed unit manufacturer would make such a mistake. lol!
This has happened quite often with just K units we have fitted.
Perhaps we can up sell by offering heated external panes to combat this green attitude every one has adopted .
Heated external panes. Dan – another one for you!
Sleep with the A-Rated window open…
(you can have that one)
As you say RCG, it shows that the windows are doing there job and preventing the heat loss.
Dan, In the 2 years we have been selling PVC-U Thermal Inserts, I’m suprised our marketing dept. haven’t thought of adding the fact that PVCU “reinforcement’ solves external condensation!!
In all seriousness though, although they allow A ratings to be achieved without the use of low iron glass, it’s not the low iron glass that causes the condensation.
It does still clearly illustrate the fact that most heat loss occurs through the edge of the glass, even with the use of warm edge spacer bars.
Pilkington do a very good technical advice sheet on this which you can get through calling the St.Helens help line.
I have a copy on file so If I can help anyone directly, RCG please pass on my contact details.
Phil – yes, I hadn’t thought considered the warm edge aspect for the reason the condensation occurs at the centre pane.
Mark – yes, I could do with having a copy. I’ll email you, as I need to supply a copy to my wife. Did I forget to mention that the householder is me???
SGG also do a pdf that offers an explanation here http://uk.saint-gobain-glass.com/upload/files/condensation_on_glass.pdf . It happens occasionally to some of our customers , unfortunately they often think the explanation is all bull , still if it can happen to 1.1 U-glass D rated windows, I guess it must be obligatory in A rated !!!!!
RCD , as a matter of interest , what is the width of the window that you are having the problem with?
RCD whoops Sorry Matthew …. where is the edit text button when you need it
Kevin – all of the windows are the same, no matter what the size of the frame is.
A brilliant example of the law of unforeseen consequences. We have had similar examples with argon filled units.
I guess if the problem is only occasional and clears quickly then the customer will accept it, but if more persistent then its going to be a real problem for all of us.
Ian – you are right. Unforeseen consequences.
I’m aware of a LOT of instances where consumers have complained about this. We’re fitting nearly all A Rated windows now.
Most customers accept the explanation that it is just the windows working extremely well, but one customer has already requested the glass be changed for normal glass. Clearly, someone not concerned about climate change
I’ve been informed by our glass supplier that we are not allowed to change the units to anything lower than K otherwise we’d be in trouble with the relevant bodies, so if you are getting the misting with Low E then there is nowhere to go.. However if the guy wants to change back to paying high bills tell him he has to keep the old glass in case he gets inspected or wants to sell his house in the future. You can bet the surveyors will pick up on it.
If the customer fits radiators on the outside walls under the windows and turns them on for cold days the condensation will clear fairly quickly. This could provide new sales opportunities for installers who could add these new external radiators to their product offering
In all seriousness this is just one more of those slightly uncomfortable choices we are all at some point going to have to make; would we prefer our condensation inside or outside? – it is a perfectly normal natural phenomenon.
Your commnents about A rated windows and condensation on the outside are not restricted to A rated windows the same is true of any window containing a D.G.U made using a soft coat glass i.e thermoglass or the like. The inclusion of low iron, warmedge spacer and argon will not highten the condesation issue. The comment that condesation did not appear before with low e units, were they soft coat or K glass? if the latter then that would explain why it was not previously a problem. Simple fix use K not soft coat but this will effect the performance or the other alternative use active self cleaning glass as the outside pane problem solved. Having said all this lets not forget this problem is restricted to sunny mornings with a cold snap and how many of those types of days do we get in the UK now.
When I first came into this industry in the early 80’s during the halcyon days of aluminum & timber sub frames, condensation on brand new windows was the dread of every installer,hence the rapid inclusion of numerous disclaimer clauses in the small print of the sales contracts.
Does this mean I need to amend my current contract to exclude EXTERIOR condensation? lol
Michael John
Unfortunately switching from soft coat to Pilks K is unlikely to solve the problem completely. We have certainly had instances with outside condensation where K has been used.
Alan Fielder makes a good point however, how many consumers do you here complaining of that horible frost on my roof every cold morning, please come and take out my new loft insulation so the frost melts quickly and I can be like the rest of my neighbours in the street? Surely this is a small price to pay if the homeowner is saving money and cutting CO2 emissions.
As an industry we are going to have to start highlighting this at the point of sale.
I sell and promote a warm edge product into the market and i have seen this s few times, it seem to me that the windows are doing what they were sold for, keep heat in the home, as we all know “the house is a home when the spacer is foam”
just like the houses that have the best roof insulation, in the winter there the ones with snow and ice still on them, the poor roof has no snow and ice its all melted away with heat loss.
mel jones
To all concerned
We have had people commnent they have seen it before with both low e and K glass, so why now will it become more of an issue than previously? this is not a new issue specific to A rated windows but an old problem that has never really been a problem. Are we using this as a reason not to install A rated windows beacause we don’t want the extra cost involved, costs that we all feel the end user will not pay in this depressed market. If it was mearly the condensation issue you would have to think there is a price to pay for everything, save the planet have condensation after all you can’t make an omlette without breaking an egg.
Michael
I think the consensus of opinion seems to be that condensation on the outer pane is there because the windows are performing well as an insulator. If anything this has made me more convinced to sell more energy efficient windows as I can now physically see the proof on my own windows.
It’s a small price to pay having the odd morning with external condensation on the glass. Our company never had any noticeable concern from customers about this ‘feature’ until we started marketing and installing a lot of A Rated windows this year. Customers are right to question why this is happening so the lesson for me is to ensure that they are informed at the point of sale that this may occur. We need to get the message across of just how well the windows will perform.
Many thanks for all the comments.
RCG
Hmmm – that’s a tricky one. After all, windows are for looking out of.
We did have a similar occurrence here at the Fabulous Photo Gifts office when a customer, upon receiving their photo jigsaw, rang to complain that they weren’t happy because the pieces were irregular shaped.
That took some explaining.
Jonathan.
tell your wife to think herself lucky that when she wakes upon that cold autumn morning that the ice is on the outside,when I wake up we have ice and condensation on the inside Brrrrrrrrrr.Could really do with investing in a new product on the market called Central Heating!!!!! lol . On a serious note we too have had several customers inquiring about the same problem as yourself and after speaking to them and directing them to the relevant websites etc I have found that we have had more of a positive reaction rather than negative. good to see your back on line and looking forward to glasstalk
Andy
Andy – yeah, see you at Glasstalk.
As it happens on the shaded non sunny windows Activ or Bio Clean will solve the problem, so this needs to be taken into account during the survey/sale another option to upsell…
Scott, I would guess though that you could not sell these products as A rated as they would filter out your solar gain
. I think that they may not even achieve a C rating so will not comply to the 2010 regs. Is It dificult to upsell a product of lower specification , that may not comply to regs ? Besides if it solves the problem of condensation on the outer pane it is purely conducting more heat from inside and is therefore less efficient.
Perhaps an application of clearshield from Ritec would solve the prolem plus cutting down on the cleaning costs etc
It needs to be Hydrophilic like Activ or Bio Clean (which incidently do not filter out solar heat gain and so make no difference to the internal low e pane) as opposed to Hyrophobic like Ritec, Allclear, Glassguard CG100 etc which all repel water and cause tiny droplets (misting up) with a Hydrophilic coating the water can not form into mist (tiny droplets) hence its use inside premium face masks and goggles etc.
Nice and techi hey
One recently (9/09) installed West facing window has exactly the same outside condensation problem. It occurs early in the morning and usually disappears mid morning. The other new windows facing South and North do not show any outside condensation.
Seattle area, Eastside
[...] behind furniture, or in cupboards. I have also seen complaints about condensation appearing on the OUTSIDE of A-Rated windows, which is just as [...]