Condensation Troubleshooting:

What is Condensation?

All air contains some water in the form of vapour which unlike the steam from a kettle, cannot be seen or felt. When damp air comes into contact with a cold surface, at least some of the water vapour will condensate into water and resulting dampness. The amount of water vapour air can hold depends on its temperature. Warm air indoors can hold more than cold air and so the risk if significant condensation is increased. Modern homes are significant producers and insulators of water vapour. An average family of four through activities like washing, cooking and drying clothes can produce as much as 4 or 5 gallons every 24 hours.

Controlling condensation means striking a balance between the way you heat, insulate and ventilate your home. Replacement windows will improve the insulation but will usually also reduce the amount of ventilation. This can be enough to aggravate an existing condensation problem or create one where there was none before.

There are two basic ways in which the problem can be tackled.

1. REDUCE MOISTURE EMISSION AT SOURCE.

Un-vented tumble dryers, paraffin or gas heaters which discharge combustion gases into the room produce large amounts of water vapour. Vent tumble dryers through an outside wall and avoid the use of these type of heaters if possible. Laundry and clothes drying should be carried out elsewhere. An external utility room perhaps. Kitchen and bathroom doors should be kept closed during cooking and bathing to minimise the migration of water vapour to other rooms.

2. REMOVE EXCESS MOISTURE FROM THE AIR.(CONSERVATORIES)

The simplest method is by ventilation, either by regularly opening windows and vents on fine, dry days or by fitting extractor fans in the kitchen and bathroom. An extractor fan should be fitted as close to the vapour source as possible i. e over the cooker, and used immediately after the steam has been produced. Open fires also provide a good source of ventilation. Unfortunately, ventilation always results in some heat loss and occasionally, the external air contains as much water vapour as that on the inside. An alternative approach would be to install either an electric dehumidifier or heat exchange unit.

Heat exchange units are normally attached to an outside wall and take the warm, moist air from the atmosphere and replace it with what is normally, drier air from out of doors, at the same time transferring the heat from the moist air leaving the property to the cooler air that is entering the property. Dehumidifiers are usually self contained and simply plug into the mains. They work along the same lines as a refrigerator and extract the excessive moisture from the atmosphere.

Additional heating of the air may help, as the warmed air will take longer to cool at any cold surface, and give the existing ventilation more time to operate. But in extreme condensation cases heating can only be effective if it is used for long enough to raise the temperature of the cold surfaces, which seldom happens when heating is used intermittently.

Double glazing will result in warmer window surfaces and will combat condensation caused by ineffective insulation of properties of single glazing, but, in the event of inadequate ventilation, any anti-condensation benefits may be cancelled out by reducing the level of ventilation that previously occurred through the old, draughty windows.