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The Top 10 Causes of High Humidity in Your Home

The Top 10 Causes of High Humidity in Your Home

Have you had enough of bubbling paint of your walls, mould build up on your ceilings and condensation spoiling your views? Here we will show the top 10 causes of humidity in the home and what can be done to prevent it.

It is also 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. 

Not to mention that breathing air from a mold infested area is not even close to being healthy.

And, that mold particle infused air gets out of the bathroom as you open the door. And, it spreads throughout the entire house.

Therefore, to avoid mold development, “hurting” the air you breathe, and damaging of your bathroom surfaces, I recommend cutting down on the heat.

By heat, I mean use less hot water and there will be less steam coming out.

Or, if you can’t live without steaming hot showers, buy a dehumidifier to help in preventing the mould and condensation build up.

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 boiling a kettle will not only create condensation without proper ventilation, by means of open windows or an extractor fan, but your kitchen cabinets can get all warped and starts falling apart in a matter of a few months.

We suggest using a dehumidifier in your kitchen area to prevent moisture build up in your kitchen cabinets which would prevent them warping. 

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. To prevent this use a dehumidifier whilst drying your clothes. Not only would it prevent condensation and mould build up but it will also speed up the drying process. 

4. Gas 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.

We recommend using a dehumidifier in conjunction with your gas heater to prevent the high humidity levels. 

5. Bad Ventilation

The quality of the air in your home is directly tied to how good your ventilation is. If the ventilation is good, the quality of the air will also be because it circulates and refreshes itself regularly. However, if you have bad or no ventilation, the air becomes stale and various problems, such as unwanted pathogen development can occur.


Also, with bad ventilation, the amount of humidity that builds up inside the home through showering, cooking or other ways I talked about, stays there. This can only lead to mold development and dangerous mold particle floating freely in the air you breathe.


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. You could consider buying an air purifier to clean this air. 

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.


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. In order to extract this moisture from your building material we suggest using a dehumidifier which will extract moisture from any organic material. 

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. If not, the material can remain humid on the inside. And, that moisture will come out later and ruin your work and bring health problems as well. You can however speed up the drying process by using a dehumidifier

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 areas with high rainfall, have high humidity levels due to evaporation. Humidity is especially high in warm, tropical areas. We suggest using a dehumidifier in your home to prevent high humidity levels. 

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. To prevent the musty smells we suggest using a dehumidifier

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. You can use a dehumidifier to prevent these high moisture build up in your home.

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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