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Why Mould is Worse In Winter

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Why Mould is Worse In Winter

By Ruth MacEachern

Product Manager

Nov 27, 2023

Mould is a common problem in many homes, especially during the winter months. Mould is a type of fungus that grows in damp and humid conditions. It can cause various health issues, such as respiratory infections, allergies, asthma, and skin rashes.  During the winter, many homeowners discover patches of mould growing on their walls.

What causes mould in homes?

Mould spreads by way of microscopic spores that are carried on the air.  Until they arrive in a place where the conditions are right for them to start to grow, the spores are inert and can remain in a dormant state for long periods of time, but when they find a space with moisture and a source of nutrition, they can grow into a large colony very quickly.

Mould in homes will mainly grow in damp patches where moisture from the air has been able to soak into a surface.  Bathroom walls and ceilings and other areas with high levels of humidity are prone to mould growth.  As the temperature of the air falls, the water vapour that it carries is released onto cold surfaces forming droplets of condensation that create damp patches.

During the winter months, the temperature difference between the warm air in your home and the cold air outdoors is much larger, and as a result, you will often find more condensation on your windows and on exterior walls.

Another factor that contributes to mould growth in the winter is that people tend to spend more time indoors, with the windows and doors closed. This reduces the ventilation and airflow in the home, which traps the moist and stale air inside. This also increases the concentration of mould spores and other pollutants in the air, which can be inhaled or come into contact with the eyes, nose, or mouth.

What are the health risks of mould?

Mould can affect your health in various ways, depending on your sensitivity, exposure, and immune system. Some of the common health effects of mould are:

  • Allergic reactions, such as sneezing, runny nose, red eyes, and skin rash
  • Asthma attacks, which can cause coughing, wheezing, and breathlessness
  • Respiratory infections, such as bronchitis, pneumonia, or sinusitis
  • Immune system suppression, which can make you more vulnerable to other infections
  • Fungal infections, such as aspergillosis, which can affect the lungs, sinuses, or other organs

The presence of mould in a home can affect everybody to some extent, but some groups are more at risk of developing serious health problems from mould if they have a weaker immune system or an underlying health condition.  If any of the following live in your home and you discover mould growing, it is even more important to treat the problem:

  • Babies and young children
  • Older people
  • People with existing skin problems, such as eczema
  • People with existing respiratory problems, such as allergies and asthma
  • People with a weakened immune system, such as those undergoing chemotherapy

If you have any of these conditions, you should avoid exposure to mould as much as possible. If you experience any symptoms of mould-related illness, you should seek medical advice as soon as possible.

How to prevent mould in homes?

If you have ever found mould in your home, you may have tried to simply clean it from the surface using a fungicide or dilute bleach.  While this is effective at removing the visible growth of mould, it does not stop mould permanently.  Unless you take steps to reduce the moisture in your home and improve the airflow, the mould will always grow back.

There are some things you can do to reduce humidity including:

  • Fix any leaks or damp problems in your home as soon as possible
  • Insulate your walls, windows, and pipes to prevent condensation
  • Avoid drying clothes indoors or putting towels on radiators
  • Ensure that you use lids on pans when cooking on the stove
  • Always use your extractor fans when cooking, showering, or bathing
  • Air out your rooms regularly by opening the windows and doors for at least 10 minutes a day

These steps will help you to reduce condensation, but the only truly effective way of preventing mould permanently is to improve the ventilation in your home.  Fitting more modern extractor fans in your bathroom and kitchen will help to remove moisture from the air much more quickly when cooking or bathing and reduce the risk of condensation at source.  Designs such as the EnviroVent Cyclone 7 fan feature a moisture sensor that adjusts the power level of the fan to increase the airflow and remove water vapour more quickly. 

If mould is growing away from sources of moisture, it is likely that there is insufficient airflow in your home.  While house ventilation systems such as the EnviroVent ATMOS draw fresh air into your home from outdoors to displace the humid air.  Positive Input Ventilation systems distribute fresh air into all rooms and stop condensation and moult throughout your home.

Find out more

If you have discovered mould growing on your walls, you need to act quickly to protect your health.  Enter your postcode below to book a free home survey from one of our local ventilation experts.  They will visit your property and identify the sources of condensation in your home before providing you with advice about the best way to solve your mould problems for good.

Simply enter your postcode below to find a specialist near you.