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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