The Truth About Condensation in Homes and Whether or Not Replacement Double Glazing Eradicates it

The Truth About Condensation in Homes and Whether or Not Replacement Double Glazing Eradicates it

Have you started noticing condensation on your double glazed windows?  Double glazing condensation can occur the outside pane of glass or elsewhere on the window.  Naturally this can be alarming, particularly if the windows or doors are new, but it is not necessarily something to be concerned about.

There are many factors causing condensation but double glazing will never eliminate it. For example, where new double glazed windows have replaced old single glazed windows such as old crittall windows or single glazed timber windows you may be surprised at the presence of condensation.  After all, double glazing is supposed to eliminate condensation isn’t it?

The presence of condensation may also be particularly evident in the Spring or Autumn. But why is this, what is condensation and should your new aluminium double glazed windows even be allowing double glazed condensation in the first place?

All windows will condensate in some way.  You must never believe any double glazing salesperson that says “our windows will eliminate condensation”. This is untrue and completely misleading. New windows can never completely eliminate condensation.

What new double glazing will do is improve the current level of condensation on your old windows.  This is because the thermal properties of modern aluminium frames and the high specification of modern double or triple glazing will be far superior than single glazed windows and non-insulated frames.  All the modern aspects of today’s windows play a part in reducing condensation but nothing can eliminate it.

The presence of condensation is down to several factors, but the main ones are how we live in our homes and what we do that causes moisture in the air.

Modern buildings are now very well insulated both in their construction and of course windows.  In older buildings that are less well insulated air flow changes are more frequent.  In modern buildings the water vapour that causes condensation is unable to escape through old windows, chimneys or the structure and has to settle on the first cold surface. This will often be the windows but can also be on bathroom tiles or walls.

The bottom line is that water vapour is the cause of condensation

It is modern life and the advances in construction products that all play a part in causing condensation in the home.  Here are some common causes of double glazing condensation:

Simple cooking and the steam generated from pots on the stove all generate water vapour.

New build properties contain a huge amount of moisture until they dry out completely.  Consider how exposed to the elements the building was during its construction and until it was sealed by the roof or windows.  Over 6000 litres of water are estimated to have been absorbed by a typical dwelling during its construction.

Heaters are also a cause of moisture in the air.

Breathing whilst we sleep is well known to produce several litres of water vapour during the night.

Drying washing indoors are also significant sources of water.

Single panes of glass found in old single glazed windows simply cannot retain any heat. As the glass has a lower temperature this lets moisture in the air condensate on the cold surface. This is why single glazed windows condensate.

By comparison, double glazed windows offer two pieces of glass and therefore retain the heat inside the room. Old double glazed units were simply two pieces of glass with an air space.

These still let out some heat but performed better than single glass.  Modern double glazing with sophisticated glass coating technology, high specification sealants and spacer bars and the presence of argon gas between the two pieces of glass all substantially reduce the loss of heat from inside the room.

Therefore the presence of condensation is unavoidable in our dwellings, but there are of course steps you can take through adequate ventilation combined with sufficient heating to reduce it as much as possible. In fact, fitting thermally efficient double glazing can make an existing condensation problem worse if the room(s) in question do not have enough heating and ventilation to reduce the pre-existing propensity for condensation.

There is always the possibility of some condensation forming on double glazed windows.  Condensation on the outside of double glazed windows is nothing to worry about, as is condensation on the inside of the window (other than the latter is rather annoying as sometimes small water pools form on the window cill).  However, if the area in between the two glass panes is misting up or showing signs of moisture then the sealed unit is failing and should be investigated to see if it has “blown” and therefore lost its thermal efficiency..

Condensation on the inside of your windows may be a sign that there is excessive moisture in the air, aside from the inconvenience of having condensation, you should consider what effect this could have on the plaster work and wood in your home.  As previously stated, ensure that there is plenty of ventilation flowing through your home, as well as enough warmth from your heating system, and this will go a long way to reducing condensation.

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