The definition of condensation according to the Encarta English Dictionary (U.K.) is
So, we're all aware of what it looks like but what is condensation doing to your home?
These are just a few of the issues that can be caused by condensation in your home.
In a nut shell, condensation occurs when warm air, containing water vapour, comes into contact with a cool surface which has a temperature below the dew point of the water vapour.
This causes the water vapour to cool and condense, forming tiny droplets which we refer to as condensation.
Water vapour gets into the air within your home from a huge variety of sources but the most common are:
Once this water vapour is in your home it doesn't always make its presence visible immediately in the form of condensation. If the temperature of the internal walls and window surfaces etc. are above the dew point then the water vapour will not condense and you’ll not be aware that it’s even there.
Now that we understand what condensation is and how the water vapour gets into your home we need to understand why it then forms as condensation on windows and other surfaces in your home.
The water vapour in your home will float around invisibly in the air until it hits a cold surface and condenses.
Why do we see it on windows first?
Windows tend to be the first place you'll notice condensation because the surface of the glass is a good conductor of heat and will therefore normally be colder than the other surfaces in the room.
Especially if your windows are single glazed.
If your windows are double glazed then the inner pane will be a little warmer, and if they're triple glazed the inner pane will be warmer again.
Therefore, if you had a room with one single glazed window, one double glazed and one triple glazed window, on a cold day the triple glazed unit would have the least condensation and the single glazed unit would have the most.
In the recent past our homes were leaky and cold as they weren't particularly well insulated and gaps in the building fabric allowed drafts to occur.
This meant you didn't get condensation very often, as the draughts allowed fresh air (containing less moisture) in to replace the moisture laden air already in your home.
Nowadays we're all obsessed with having air-tight homes which will make condensation worse unless we install the correct form of ventilation. This is because the stale water vapour laden air isn’t replaced with fresh air as there are no draughts and restricted ventilation.
So we now know that ventilation is essential in order to minimise the risk of condensation. But how do you achieve adequate levels of ventilation?
Building control does insist that adequate ventilation is provided to your home by making you install vents, trickle vents to window frames and/or mechanical ventilation etc.
These methods allow adequate and controlled air changes, however occupants tend to close trickle vents and block vents in order to try and keep the heat in and the drafts out.
Below are some additional articles I’ve written to help you increase your understanding of what condensation is:
For obvious reasons condensation will be more obvious in rooms where there is a moisture source, such as bathrooms, kitchens and utility rooms where you use hot water and therefore produce steam.
The other rooms where you’ll tend to find a lot of condensation is bedrooms. Very few of us realise that while sleeping we breath out around 2-3 litres of water vapour each per night .
As you can see, when trying to explain “what is condensation” we’re thrown into a lot of interconnected areas. The links above will take you to separate articles which will help you understand the basics a little more and help you reduce your condensation issues significantly if not stop them altogether.