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 not;

1. The level of moisture in the air
2. The air temperature of the room
3. 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 winter.

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 activities.

1. The temperature drops overnight and the surface temperature of the windows decreases.
2. The moist air in the room comes into contact with the window and condenses.
3. We wake up in the morning to water dripping down the windows.
4. 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 dry...

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 bathroom.

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 reaction?

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 answer.

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.

The solution

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 here.