Is your home humid? How to detect humidity in the home - and why it can be bad for you

It can cause mould, warped floorboard and even breathing problems – but do you know the signs of high humidity in your home?

As the weather turns even colder, thoughts turn to cranking up the central heating and cosying down in front of a fire.

As cosy as that sounds, there’s a slight problem with all this shutting yourself indoors – humidity.

[Read more: How to get rid of condensation in your home]

Humidity might be something you’re more likely to associate with summer, but in the winter months, it can be just as high, especially in the home.

Sally Fok, co-founder and MD of air conditioning and dehumidifier producer EcoAir, explains: “Humidity problems in the home are caused by excess moisture in the air, which can come from a multitude of sources, including condensation, rain entering the house, leaking pipes, rising damp or flooding, moisture in construction materials, faulty or inadequate seals on door or window frames, faulty damp proof course, inadequate ventilation, high rainfall, and even everyday household activities such as cooking, boiling the kettle, taking showers, running baths and drying laundry.

“Even our breathing causes humidity!

“By turning heating on in the winter months and closing doors and windows to keep our homes warm, we significantly reduce ventilation and air circulation. Rain and melting snow create increased levels of moisture that enter our home through the windows, floors and walls, particularly in older buildings.”

Problems of high humidity

A high humidity in the home can cause a number of problems, including rotting wood around windows and windowsills, corroding electronics and appliances, spoiling wooden instruments or books, causing food to go stale quicker, triggering mould and mildew, which can damage wallpaper, carpets, fabrics, soft furnishings or even causing structural damage to foundations.

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Excess moisture in the air can also cause a number of health issues, providing optimum conditions for microorganisms and airborne allergens, such as dust mites or mould spores, to breed, thrive and spread.

“Airborne microorganisms such as viruses thrive in humid conditions” says Sally. “As soon as humidity levels rise above 60%, viruses survive longer and breed quicker, escalating the risk of contagion.

“High humidity is not uncommon in UK homes during the cold, wet winter months. With a tendency to turn up the heating and close doors and windows to keep a house as warm as possible, we significantly reduce air circulation, causing moisture generated inside to become trapped. This creates exactly the warm, damp conditions that microbes need to thrive.”

10 signs of high humidity in the home

• Condensation, mist or vapour on windows or glass doors.
• Appearance of mould or mildew on window sills or tracks (black, dark or green gunge).
• Rotting wood or paint peeling around doors or windows.
• Black mould spots on walls or ceilings.
• Mould around the bath, shower, sink or toilet.
• Musty smell in the air, on bedding, carpets or soft furnishings.
• Yellowish-brown water stains or fluffy white salt deposits on walls (this will usually be due to a leak or rising damp).
• ‘Tide-lines’ along the bottom of basement or ground floor walls or skirting (due to ground water run-off problems).
• Creaky, crooked floorboards or door and window frames that don’t fit properly (wood warps when exposed to moisture).
• Allergic reactions, asthma attacks, respiratory problems or skin infections.

[Read more: 5 ways central heating could be making you ill]

What to do if your home has high humidity

• Open windows – even in winter.
• Leave fans on when cooking and showering.
• If your windows have vents, leave them open as much as possible.
• Move houseplants into one room.
• Take colder showers.
• Invest in a fan or dehumidifier.

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