The perennial complaint of the general public to the window industry at this time of year: “I’ve got condensation on the outside of my windows, what’s wrong with them?”
Obviously we all know there is technically nothing wrong with them. It’s literally energy efficiency in action. But that doesn’t stop the public every Autumn and Spring ringing up installers in their droves in a panic as they get up in a morning and not be able to see out of their new windows.
Yes, it’s that time of year again. Time to break out the prepared speech and be ready for those morning phone calls about external condensation.
Honesty and education
In my experience I have always found it best to be upfront and honest with my customers and tell them that on some morning at certain times of the year they are going to get up and find they can’t see out of their windows, on certain windows in their home. I then go on to explain in a bit more scientific detail as to why they are going to see what they will see, and in the end they accept that it’s part and parcel of the installation and at least the windows are doing their jobs.
Don’t get me wrong, we still do get the odd phone call from panicked home owners thinking something drastic has gone wrong with their windows. A quick explanation as to why and then they’re fine again. But this is where education and honesty has a part to play in all of this.
At the start of the sales process, so long as the installer is up front and explains the why’s and what-for’s about external condensation, most home owners should be fine and reasonable about it all. For the scientific explanation, this is how Saint-Gobain describes it:
Surface condensation will appear on face 1 of the insulating glazing if the temperature on this face of the glazing is significantly lower than the external air temperature and if the dew point (i.e. temperature at which water vapour becomes liquid) of the external air is higher than the temperature of the glass.
The surface temperature on the outside of glazing is dependent on:
-The heat flow from the interior passing through the glass. This depends on the difference in temperature between the internal surface and the external surface of the glazing and the U-value of the glass
-The heat exchange by convection with the external air
-Heat loss by radiation mainly to the sky.
Various studies and measurements carried out by the CSTC have shown that heat exchange by radiation is relatively limited in overcast weather. However, when the sky is clear at night, there are significant heat losses to the sky.
Show a home owner this and they should be further reassured that all is well during Autumn and Spring. Still, it doesn’t stop the odd customer absolutely kicking off over what is a climatic and very temporary phenomenon. Yet, this is the kind of world we live in right now.
But there is something that can be done, and I’m wondering whether standard glass specs should be changed to combat external condensation.
Anti-condensation glass as standard?
External condensation will be a problem for many home owners who have recently had new windows installed. Something we will have to live with as an industry. But it’s not as if there isn’t absolutely anything that cannot be done to stop it.
For example, Saint-Gobain has their SGG VIEWCLEAR® II product to combat condensation. Pilkington has their Anti-Condensation Glass product too. Both developed to combat seasonal issues such as these. I am not aware as to the cost uplift of these products. But if they’re not bank-busting, then perhaps this is the time of year IGU manufacturers should be going out to installers and fabricators to push the benefits of these products. At least during this time of year to push extra sales, but maybe as standard all year round.
I don’t know how these two types of products affect things like U-Value, if anyone from Pilks or Saint-Gobain is reading please let us all know via the comments section below. But if there is no difference, and you can achieve the same energy efficiency levels as now, then I don’t see the harm in installers offering this as part of their standard glass offering to home owners.
It’s an added USP over competitors too. By first educating the home about external condensation and showing them what happens, it becomes a platform for that installer to go on to explain that by using the glass they do, they can have the same levels of energy efficiency but without the ugly external condensation during Autumn and Spring.
External condensation sounds like one of those short-lived issues our industry should have then move on from. The products are already being made to bypass it, they just need to be used on mass to eradicate future problems.
You manning the phones yet?
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In in the interests of balance, Guardian also offer an anti-condensation product called ClimaGuard Dry…
Thanks for your contribution. Good to see Guardian has their own offering against condensation. Perhaps it won’t be long until we saw all variants offered as standard.
My impression is that in most cases the uplift outweighs the relative benefit. Its a luxury rather than a must have :/