Curing condensation problems
Condensation on windows spoils the look of the windows, creates mould,
can destroy wooden frames and is a pain to mop up every morning.
It can be greatly reduced/prevented completely, but in order to win
this battle you need to understand your enemy!
If you are confused and want to talk to someone then please do
call us on 01483 234900.
Why do I get condensation?
There are three factors that decide whether you get condensation or
The level of moisture in the air
The air temperature of the room
The surface temperature of the windows
The more moisture there is in the air the more likely it is that you
will get condensation. Moisture in the air comes from drying
clothes in the house, boiling vegetables, putting the kettle on,
bathing, showering, open flame gas style heating, rain soaked
clothing, breathing and the damp British weather.
The warmer you keep the air in the room the more moisture the air can
hold and the greater the difference is likely to be in the air
temperature and the surface temperature of the windows overnight in
The colder the windows are the more likely it is that condensation
will occur and the less moisture is required for condensation to
happen. This is why we see more condensation in the winter and
less in the summer.
The condensation cycle
We put moisture into the air during our normal daily
The temperature drops overnight and the surface temperature of the
The moist air in the room comes into contact with the window and
We wake up in the morning to water dripping down the windows.
We mop up the moisture, take a shower, put the kettle on and take a
load of washing out of the washing machine and put it in the airer to
Breaking this cycle
Look at where you are creating moisture and see what can be
done to prevent moisture from getting into the air. For example
putting lids on saucepans whilst they are boiling, doing a final rinse
when using the washing machine, always maintaining and using an
extractor fan in the Bedroom.
The honest answer though is that we will always produce moisture and
we will do so on a daily basis.
Opening windows to solve the problem
Opening windows for around twenty minutes will exchange all
of the air within a room with air from outside. Everything will
be exchanged, moisture as well. Sounds great but you need to
think this through.
Is the air coming in damper or dryer than the air going out (and how
can you tell?)
Is the air coming in colder or hotter than the air going out?
Is the air coming in cleaner than the air going out (do you live by a
main road for example)
Is it safe to leave a window open?
Will the exchange of fresh air bring in allergens to cause an allergic
If you look at
this data on the BBC website for London it tells us that the
average relative humidity throughout the year is high enough to create
mould in your home (above 68%rh) and certainly high enough to cause
condensation. True if you heat the air when it comes in this
will dry the air but this would not be practical from around April to
October and very expensive for the rest of the year. With fuel
bills on the increase people are not happy opening a window to let the
air they have already paid to heat out and cold, damp air that needs
to be heated all over again in (and then repeat this cycle on a
regular daily basis).
So when you look at it opening windows is not necessarily the best
answer and is certainly not necessarily the most cost effective
Dehumidifiers and condensation
A dehumidifier is a simple but effective machine that removes
the excess moisture from the air and turns it into water for you to
pour away. This means that you will not have enough moisture in
the air to condense on the windows in the same way as it has been
doing in the past and that the air will feel warmer because the 'damp
chill' will be removed the air, thermostats can be turned down and
heating bills will be reduced.
Dehumidifiers saving you money
Before you can feel warm every single water molecule in the
air needs to be heated up for the air temperature to increase.
The more water molecules there are the longer and more expensive this
process is. A dehumidifier removes the excess moisture and
therefore there are less water molecules to be heated up and therefore
the air becomes warmer faster and it costs less money for this to
happen. You will find that you turn the thermostat down as a
result. Hence a dehumidifier will save you money.
What about the money spent running the dehumidifier?
A dehumidifier is generally used during the winter months and
in winter heat in the home is a good thing as we need to keep warm.
The energy that a dehumidifier uses is returned top the room as heat.
Any other radiators or heaters in the same space as the dehumidifier
can be turned down. Therefore no energy or money is wasted as a
result of using the dehumidifier.
Regardless of the cause of your damp problem it all comes back to an
excess of moisture and a dehumidifier can either solve the issue
completely or bring the moisture under control until you have an
opportunity to bring the structural problem under control.
Details of our domestic dehumidifiers for the home can be found