14 | JUNE 2017
News
Read online at www.proinstaller.co.uk
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.
Condensation can be a nuisance.
Depending on where the condensation
occurs - facing inside, outside, or between
panes - installers can be limited as to how
much they can help. Here are some of the
most common questions we’re asked about
condensation, along with explanations and
some tips on how installers can help.
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 exter-
nal 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. Pilkington
Anti-condensation glass can also be laminat-
ed, toughened, bent and incorporated into
insulating glass units (IGUs).
2) Why is there condensation
on the outside of some
windows, but not others?
You may notice that not all panes are af-
fected 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. This means
the effect isn’t seen to the same degree as a
window without self-cleaning glass.
3) Why is there condensation
between my glass panes?
Condensation between panes usually oc-
curs 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 l