What causes condensation on windows?
Condensation occurs due to an abundance of moisture in the atmosphere, which settles on cooler surfaces, typically seen on windows during times when the exterior is chillier than the interior.
The air enveloping us is saturated with invisible, minuscule water particles. In conditions of higher humidity, these water particles are denser and more prone to ‘condensing’ on surfaces.
Consider the phenomenon of a chilled beverage glass appearing to perspire on a warm day. This effect is caused by the moisture in the warm air meeting the glass’s cool surface.
In warmer air, the separation between molecules allows them to ‘carry’ moisture. However, as the air cools, the molecules draw closer. When they are sufficiently close, they coalesce into a visible liquid, a process referred to as reaching the ‘dew point’.
At this dew point, water droplets become visible on surfaces. Examples include:
- Water droplets on a mirror following a hot shower
- A kitchen window fogging up during cooking
- Windows gather moisture when clothes are dried indoors
Condensation is not exclusive to windows; it can occur on any cold surface, particularly in spots prone to moisture accumulation:
- Windows covered by blinds or curtains
- Behind bulky furniture placed against a cold wall
- Within a built-in wardrobe on an outer wall
How can condensation damage windows?
Stagnant water, over time, poses a risk to any surface it settles on, including those deemed waterproof. Consider the formation of limescale and the growth of mould as examples.
Although uPVC windows are designed to be resilient against moisture, the combination of persistently damp seals and intense sunlight can lead to their deterioration. The repetitive process of expanding and contracting can cause these seals to dry out and fracture.
Wooden window frames are particularly vulnerable to such damage:
- Paint and varnish may start to flake off
- Wooden elements can become dry and develop cracks
The primary issue with accumulated water and moisture is the development of mould. Without intervention, mould can cause both uPVC and wooden materials to become damaged and discoloured.
Crucially, mould poses a significant threat to health, making its management paramount.
Condensation and black mould
The core problem with condensation lies in its potential to foster the growth of black mould.
The appearance of black mould around windows, doors, and walls is not only unsightly but could also pose serious health risks.
Mould exposure can lead to symptoms such as:
- Blocked noses
- Breathing difficulties
- Irritated eyes
- Skin irritation and itchiness
Furthermore, the World Health Organization has identified that mould exposure may contribute to various health issues, including:
- Asthma attacks
- Allergic rhinitis
- Hypersensitivity pneumonitis
- Allergic alveolitis
- Persistent rhinosinusitis
- Allergic fungal sinusitis
Additionally, there are unconfirmed reports suggesting that acute idiopathic pulmonary haemorrhage might result in memory impairment and fatigue in infants.
It’s clear that mould poses a significant threat and requires immediate attention.
Eliminating any visible mould through thorough cleaning and removal, followed by implementing strategies to reduce condensation, is essential for a healthy living environment.
How to stop condensation on windows
The primary trigger for condensation is insufficient airflow. The solution lies in enhancing air circulation to balance the moisture levels both inside and outside of a building.
Historically, homes featured imperfectly sealed windows, doors, chimneys, and air vents, which naturally facilitated air exchange.
Over the past three decades, the drive for energy efficiency has significantly sealed homes, effectively turning them into enclosed spaces that retain moisture.
While advancements have been made in heat conservation, this has inadvertently reduced the natural airflow within our living spaces.
To effectively eliminate condensation on windows permanently, the following measures are recommended:
- Boosting air circulation
- Minimising indoor moisture levels
- Upgrading to double or triple-glazed windows
The biggest causes of excess moisture that causes condensation
To effectively reduce indoor humidity and its effects, it’s essential to manage the following common sources of moisture within the home:
- Cooking activities, including the use of pans and kettles
- The use of showers and hot water taps
- Operating washing machines and tumble dryers
- Air-drying clothes on radiators or indoor drying racks
- Maintaining large indoor plants
- Storing damp firewood for wood-burning stoves
- Addressing hidden water leaks within walls or beneath flooring
- Managing rising damp issues in basements and ground-floor constructions