Preventing and controlling humidity in the home

Humidity refers to the amount of water vapour in the air. It makes indoor environments less comfortable and affects the lifespan of the materials in your home. 

Excessive indoor humidity causes condensation and promotes mould growth, which can damage your home. 

Low humidity can dry out the air and cause skin and respiratory irritation. 

Relative humidity measures the amount of water vapour in the air in relation to the maximum amount of water that the air can hold at a given temperature. 

For optimal indoor comfort and health reasons, you want to achieve relative humidity in your home, as humidity directly influences our perception of temperature and air quality. 

The ideal humidity level, where the air is neither too dry or too moist, is between 40% and 60%. These conditions help prevent mould and condensation and health issues. 

This ideal humidity level also helps to preserve materials, such as wood and paintwork, which can warp or crack if there is excessive or insufficient humidity. 

Relative humidity varies with the seasons and requires adjustments to maintain a comfortable balance. 

To control the humidity in your home, you first need to accurately measure it.  Hygrometers are cheap and easy-to-use tools that monitor your indoor humidity rate. 

To obtain an accurate reading, place the hygrometer away from direct heat sources and draughts. Smart models can provide real-time readings and alert you to abnormal humidity levels. 

Many everyday activities contribute to the humidity in your home, including cooking, showering and drying clothes indoors. 

The construction of your home can also encourage more or less humidity. Capillary humidity, or damp, occurs when groundwater is absorbed by the foundations or walls of your home and slowly rises and enters your home through porous materials, such as concrete or brick. 

This type of humidity is common in old buildings with foundations and walls that are not sufficiently protected by a damp-proof system. Dark spots on walls, peeling paint and musty odours are all signs of a damp home. 

Humidity levels have a direct effect on your wellbeing. 

Excessively high humidity promotes the growth of mould and the spread of mites, which can trigger allergies and cause respiratory problems. 

On the other hand, overly dry air and low humidity can irritate the skin, eyes and mucous membranes. 

That's why it's important to maintain a balanced humidity level that avoids high and low humidity. 

High humidity makes your indoor air feel heavier and warmer, while dry air caused by low humidity makes a room feel colder. 

Good insulation and adequate ventilation are key to maintaining optimal humidity levels.  

If your doors, windows or roof windows are old and no longer retain heat well, it’s worth replacing them. 

Here’s how to spot the signs of a humidity problem in your home before it does serious damage. Look out for:

• Persistent condensation on windows
• Dark stains or discolouration on walls
• Mould growth 

Take preventative action and respond quickly to the first signs of a humidity problem to stop it from getting worse. 

Here are five effective solutions to limit the risks of condensation, mould and damage caused by humidity. 

Water can leak into your home from your roof, walls or plumbing. Even small leaks can cause significant humidity, leading to property damage and mould growth.

Here are some steps that you can take to prevent damage from leaks:

• Fix leaks quickly: Regularly inspect your gutters, roof, windows, and water pipes for signs of leakage. Repairing leaks quickly can help you to avoid expensive remedial costs.
• Improve insulation: Install good quality insulation in your loft, walls and floors, this helps prevent moisture entering from outside.
• Seal the windows: Use caulk or sealants to seal the gaps around windows and external doors. Tightly sealed windows and doors prevent moisture from entering your home. They also reduce temperature variations and help to regulate humidity levels.
• Damp proof course: If damp is entering your home through your walls or foundations causing capillary humidity, you may need to install a new damp proof course. 

Some day-to-day activities, such as drying laundry indoors, bathing or cooking without an extractor fan, increase your home's humidity levels. Dry clothes outside when the weather permits and always open windows when doing things that produce steam. 

Ventilation is essential for keeping humidity at a safe level, particularly in steamy rooms, such as the bathroom and kitchen. 

Open your windows regularly for natural airflow and install extractor fans in your bathroom, kitchen and utility room to reduce the humidity further. You could also use a dehumidifier to remove excess water vapour and keep the air at a comfortable level. 

For optimal control, install smart systems, such as smart thermostats equipped with humidity sensors. 

The VELUX ACTIVE with Netamo system, for example, uses sensors to automatically open and close roof windows based on indoor humidity levels. 

These technologies help to maintain a stable humidity level throughout the year. 

Seasonal changes influence humidity levels in your home. In winter, central heating can make your air drier, while in summer, humidity can increase, especially during heavy rainfalls or if you live in a coastal area. 

To manage the humidity in your home based on the season:

• In winter:
  • Use a hygrometer to monitor humidity levels
  • Check your window and door insulation and fix any cold draughts
  • Install double-glazed windows and well-insulated roof windows to help maintain a stable temperature. Solar and electric automated windows will help you air your room out more quickly.
• In summer:
  • Natural ventilation helps to cool the air without increasing indoor humidity. Regularly open your windows, particularly early in the morning and late in the evening.