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What can installers do about condensation?
Phil Brown, European regulatory marketing manager at Pilkington United Kingdom Limited, part of the NSG Group, answers four common questions about condensation on windows, and outlines what installers can do to help and advise customers.
1) WHY IS THERE CONDENSATION ON THE OUTSIDE OF MY WINDOWS?
The transition to spring often sees an influx of enquiries about the appearance of external condensation on windows, especially from those with high performing low-emissivity glazing. The phenomenon is a tell-tale sign that windows are doing their job of keeping the heat in, and so is nothing to worry about.
External condensation happens because of a natural phenomenon, likely to occur in the spring and autumn, called the dew point. Put simply, the dew point is the temperature at which a concentration of water vapour in the air will form dew. If air cools down sufficiently to the dew point, it can no longer hold the moisture, forcing the water vapour to condense.
While the effect doesn’ t usually last long, there is little that can be done to avoid condensation to the outside of the window entirely without specialist glazing. Once the window pane warms from the sun, the moisture will evaporate. A gentle breeze or wind can also help to clear it.
Pilkington Anti-condensation glass offers a solution that prevents the onset of external condensation and improves the view through windows. It’ s an on-line coated product manufactured in 4 mm thickness available in both Lehr End Size( LES) and Jumbo sizes. As the coating is pyrolytic, it is durable enough to be used on surface one( i. e. facing the outside), as well as being robust and easy to clean.
2) WHY IS THERE CONDENSATION ON THE OUTSIDE OF SOME WINDOWS, BUT NOT OTHERS?
You may notice that not all panes are affected by early morning condensation, even in the same window. Subtle differences in the orientation and the position of objects outside, such as trees or a close building, can change the surface temperature of the glass to the point that one pane suffers and another doesn’ t.
Glass with self-cleaning properties, like Pilkington Activ™, may also have fewer occurrences of external condensation. As a self-cleaning glass, it is no less prone to condensation than any other glass, however its properties mean it doesn’ t allow water to form beads on the surface, meaning the effect isn’ t seen to the same degree.
3) WHY IS THERE CONDENSATION BETWEEN MY GLASS PANES?
Condensation between panes usually occurs if the insulating glass unit( IGU) edge seal fails, allowing warm air from inside a room to mix with the cold air between panes, allowing the air to condense.
The lifetime of an IGU can be maximised by purchasing one tested in accordance with Standard, BS EN 1279( Glass in building – Insulating glass units) and suitably installing it in accordance with industry standards, ideally into an appropriately drained and ventilated frame. Extra confidence can be gained if the IGU has been assessed as part of a third-party certification scheme and supplied with a formal warranty.
4) WHY DOES CONDENSATION OCCUR ON THE INSIDE OF MY WINDOWS?
Condensation usually appears on the inside of a window that faces a room with high moisture content. The obvious example of this is in a bathroom, but it can also happen in environments like gyms due to perspiration, or cafés with single-glazed windows where food preparation causes an increase in humidity levels.
There’ s little installers can do to stop the occurrence of internal condensation in bathrooms as the moisture content can be so high. However, specifying low-emissivity double or triple glazing should help in other situations, as the inside pane is less likely to get cold enough to make the water vapour in a room condense on the glass surface.
HELPING CUSTOMERS UNDERSTAND
As uptake in high performance thermally insulating glazing increases, queries about external condensation are also likely to increase. However, it’ s important to inform customers that this proves that the glass is performing as designed( and that solutions are available with Pilkington Anti-condensation glass if required).
If condensation inside of a room is becoming a nuisance, it could be worth recommending improving the ventilation through more or improved extractor fans at the sources of water vapour. Increasing the room temperature to enable it to hold more water vapour without condensing can also help. However, if it happens between panes, installers can assist by repairing or replacing the IGU.
44 » JUL 2017 » CLEARVIEW-UK. COM