The Top 10 causes of high humidity in your home

Lizelle Verrall
 November 22, 2016
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It's important to maintain the proper humidity levels in your home and workplace to keep a comfortable, healthy space. High humidity levels won't only wreak havoc on your home and possessions, but can also be detrimental to your health, as high humidity conditions are favourable to mould growth and mildew, which can lead to allergies and asthma. 

1. Showering


Bathrooms are often humid places and moisture is released into the air by something as simple as taking a shower. As the moisture mixes with the air as water vapour, it will eventually make contact with a cold surface, forming as droplets on things like mirrors or windows.
This is unsurprisingly known as condensation. The hotter the water vapour, the more moisture the air can hold and the more that can be deposited on cold surfaces.
That's why condensation becomes a bigger problem whenever you take a hot shower and there's lots of steam rising from the water.
Apart from it annoyingly misting up mirrors and windows, it can also cause problems with mould in your bathroom by quickly ruining wallpaper and other surfaces. The last thing you want to do is redecorate your bathroom only a few months after initially doing it.

2. Boiling a kettle or cooking
Boiling water on the stove, cooking or boiling a kettle will add humidity to your home as the water evaporates. This is why it can sometimes get very hot inside a kitchen and people tend not to enjoy standing over a hot stove on warm summer days. Cooking or a boiling kettle will not only create condensation without proper ventilation by means of open windows or cooker hood extractor fans, but can wreak havoc on your cupboards!

3. Drying laundry inside


A load of laundry can release up to 2 litres of extra water in into the air. Before you can wear those clothes, or put them safely away in your cupboard, you have to get rid of the water. So the everyday chore of drying clothes is actually a more scientific kind of problem: how can we dispose of at least 2 litres of water as quickly and efficiently as possible? For every load of washing you have to make the equivalent of at least two full two litre bottles of water literally vanish into thin air.

Dry your clothes inside your home (with or without a tumble dryer) and what you are actually doing is throwing about a quarter of a bucket of water into the air in extreme slow motion. Now this evaporated water has to go somewhere. With outdoor drying, this isn’t a problem, as the water simply dissipates in the air. Indoors, however, you’ll find the steam or water vapour you create quickly appearing on your windows as condensation – or worse – as damp or mould on the walls.

4. Gas heaters / propane heaters
Gas heaters burn gas to produce heat. This is called combustion. When they burn gas, they make some combustion pollutants and water vapour.
A flued gas heater has a flue or chimney to carry the combustion pollutants and water vapour to the air outside the home. An unflued gas heater has no flue and releases the combustion pollutants and water vapour directly into the room.
Burning gas always produces water vapour. If there is not enough fresh air circulating in the room, water vapour can cause high humidity and wet surfaces. These conditions encourage the growth of house dust mites and moulds. House dust mites and moulds in the home can sometimes cause health problems and may trigger asthma.

5. Poor ventilation


Poor indoor air quality is affected by the level of ventilation in a building, including how much fresh air is entering the building from outside and how effectively contaminated air is being exhausted from the house.

Good ventilation removes stale indoor air and reduces the amount of indoor air pollutants. It also helps to limit the build-up of indoor moisture, which can contribute to mould growth.
Ventilation increases the amount of outdoor air that comes indoors, however, the level of outdoor air pollution should be considered when ventilating your home.

6. Rising damp
Humidity occurs in indoor environments due to building related causes. Porous walls, rising damp, and leaks in the building are determinants for structural dampness due to elevated humidity levels. The construction of the building can also lead to humidity and unwanted moisture in the indoor environment. 
Wet materials, such as lumber stored unprotected outdoors before construction, can lead to increased humidity indoors for up to the second year of occupancy in the building.
Dampness tends to cause secondary damage to a building. The unwanted moisture enables the growth of various fungi in wood, causing rot or mould health issues and may eventually lead to sick building syndrome. Plaster and paint deteriorate and wallpaper loosens. Stains, from the water, salts and from mould, mar surfaces.
Externally, mortar may crumble and salt stains may appear on the walls. Steel and iron fasteners rust. It may also cause a poor indoor air quality and respiratory illness in occupants. In extreme cases, mortar or plaster may fall away from the affected wall.

7. Renovations


A change is as good as a holiday, but sometimes if this change means renovations to your home, it can quickly turn into a high humidity (and very mouldy) affair if some materials such as plaster cement and paint don’t have enough time to dry.

It is important to leave enough time for each material to dry properly before resuming the work.

The effects of humidity can be aesthetic, but can also be dangerous to your family’s health, especially when family members have allergies or are asthmatic.

8. Coastal air
Relative humidity is influenced by temperature and geographic location.  Warmer air holds more moisture than cooler air, and warmer weather promotes evaporation. Areas with a lot of surface water, such as coastal areas and the Great Lakes region, have high humidity levels due to evaporation.  Humidity is especially high in warm, tropical areas.

9. High humidity regions (KZN summers)
Humid weather simply exacerbates moisture problems that are often a concern in homes.
Moisture from the ground works with moisture from the humid air to generate condensation on walls and other surfaces, and create musty smells and atmospheres. In turn, this can then result in mould and mildew issues.

10. High rainfall regions (Western Cape winters)


During cold wet winter months, such as those experienced in the Western Cape and along the Southern Coastal belt region, humidity levels in the home can get quite high.

Due to high moisture levels outside the home, the excess moisture created by breathing, cooking, heaters, warm baths and showers, and tumble dryers cannot escape and result in high humidity levels inside the home.

This in turn transfers to very favourable conditions for mould growth.
For more information on our different dehumidifiers click here.

Alternatively, give us a call on 0861 388 878 or click on the Live Chat link.

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