Mold in Your Home: Causes, Dangers, Signs, and How to Stay Safe 

It’s not uncommon for people to discover mold in their homes while cleaning or after experiencing water damage. In fact, the sad truth is that at least 45 million buildings in the U.S. have unhealthy levels of mold. Mold in your home or office can remain hidden behind walls, ceilings, or under carpets for years. This can have severe health implications for many people, as nearly 25% of the population is predisposed to mold illness.
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How harmful is mold in your home?

Mold found in living spaces or in the building fabric becomes dangerous primarily because it often remains undetected for a long time. Since mold spores are already present in the air in the room, they can easily multiply. Depending on their concentration, the spores can enter the body through breathing or through the skin and cause both significant and permanent illnesses.

What are the consequences of mold on your health?

As mentioned above, mold found in living spaces often remains undetected for a long time, which is why small mold spores can spread throughout the house. The spores can form dangerous enzymes and enter the body through the respiratory tract and the skin. Depending on the concentration, formed toxins and so-called mycotoxins can trigger a variety of diseases. Most often, these manifest as respiratory problems or allergic reactions. However, some mold species, such as black mold, are also suspected of causing much more serious ailments such as cancer or organ damage. Certain symptoms may indicate impairment from mold, but unfortunately, these signs are often attributed to other diseases. Symptoms caused by mold may include:

  • Respiratory complaints, asthma, allergic reactions
  • scratchy throat, hoarseness, coughing
  • nausea
  • headache, migraine
  • Exhaustion, fatigue, insomnia
  • Burning, reddened eyes
  • Skin rash, redness
  • Lung and heart diseases


Especially for people whose immune system is already weakened by a previous illness, mold in living spaces poses a great danger. Infants or children can also suffer permanent damage more quickly, as they might have not yet developed sufficient immunity.

What are the main places where mold is formed?

In general, it is widely agreed that mold develops where it is humid. However, mold particularly likes to develop when moist air condenses on cold surfaces and the relative humidity on the surface is more than 80%. Bathrooms in particular regularly have some residual moisture due to wet towels, damp tiles, or shower stalls. However, bedrooms are also a popular place for mold to grow. This has to do with the fact that people release a lot of liquid when they sleep and therefore the humidity is high here as well. Molds also like to settle on windows, because some water condenses there in colder places. Since mold generally feels at home in cool places, it mainly booms in the winter months. The reason for this is that warm weather can absorb significantly more air than cold air. The room temperature drops more quickly when ventilated, providing a better breeding ground in addition to shorter ventilation times. Mold also likes to spread in places where there is no air circulation and where it is cool, such as behind cabinets, paneling, or furniture.

How can mold be detected?

Molds that form on various surfaces are known to generate airborne mold spores, which can enter the bloodstream through people’s skin and respiratory tract and have severe health effects. Therefore, it is important to detect and treat mold as early as possible. These 4 points and tips will help you recognize a possible mold infestation:

1. Musty, foul-smelling room air

A musty and foul odor is caused by the metabolism of mold. The smell cannot be eliminated even by ventilating and room fresheners cannot cover it. This has to do with the fact that air movements ensure that more mold spores are often carried from the walls into the room air.

2. Brownish discoloration on the walls or surfaces

Mold infestation in one’s own home can in many cases already be detected with the bare eye. The first signs are small black or brown dots on wallpapers, baseboards, joints, or silicone seals among other things. The infested areas grow over time, which is why action must be taken quickly. Since mold likes to hide behind furniture, you should also check otherwise hard-to-see places at first suspicion.

3. High humidity / damp places in the room

Since molds need sufficient water to spread, they mainly live in damp places. If rooms are particularly damp, for example, due to the drying of laundry, special attention should be paid to mold growth here. The moisture settles in the form of condensation mainly on windows, window sills, or walls.

4. Symptoms of illness that indicate mold infestation.

Because mold infestation in homes can cause irritation and respiratory illness, unexplained symptoms of illness in you or your family members may also be a sign of mold infestation. If you experience frequent fatigue, flu-like symptoms, headaches, or sleep disturbances, you should check whether mold spores are the cause.

What are the possibilities to prevent the formation of mold?

The most important measure to prevent the formation of mold is regular ventilation. In a household with four people, about fifteen liters of water is released into the surrounding air every day, which is then deposited in the coldest parts of the room if it can not escape in any other way. To remove excess water vapor, the whole house should be ventilated at least 3-4 times a day for 15 minutes each time. This is especially important during or after cooking, showering, or drying laundry, as this is when a particularly large amount of moisture is generated.

Another option would be to use alkaline wall paint, as virtually no mold thrives on it. Lime-containing wall paints also absorb moisture and thus act against excessive humidity. In addition to that, the room temperature should not fall below 16 degrees Celsius in all living rooms and bedrooms. Even in winter, walls should not cool down too much. For perfect air circulation, furniture should not be placed too close to walls, and this is especially important for exterior walls. Strongly sealed houses can consider the purchase of a ventilation system, which will ensure the optimal exchange of air in their home. While stale air is canceled in the kitchen and bathroom, fresh air is blown into the bedroom and living room.

Are air purifiers a suitable solution against the spread of mold spores?

As soon as you notice that your home is infested with mold, you should act fast. New sources can quickly appear in your home due to mold spores spreading through the air and re-depositing in damp corners. But be careful, both humidifiers and air scrubbers should not be considered to combat mold infestations. Since they generate moisture, they would further increase the humidity in your home, thus encouraging the spread of mold. Additionally, it must also be kept in mind that air purifiers do not eliminate the triggers of the problem. The cause of the overall problem should be urgently addressed with the help of professionals. However, with that being said, in order to rid the indoor air of harmful mold spores and thus also counteract the spread, air purifiers are a recommended measure. But before you decide to buy an air purifier, you should consider some important aspects. The air purifier should be really effective in filtering mold spores from the air, i.e it should be able to filter particles of the sizes 0.1µm and 0.3µm. In case you were wondering, HEPA filters can filter particles of this size. However, since mold spores are deposited on the surface of the fabric, a rapid filter change is necessary after only a few weeks if there is a high incidence of mold spores. An activated carbon filter is also recommended, which can remove the musty and unpleasant odor of mold from the apartment. If you have an above-average load of mold in your home, it is imperative that the air purifier be switched on for as long as possible. For this very reason, both the energy consumption and the volume of your device should be as low as possible, so that your air purifier does not become a further burden. In conclusion, if you notice mold in your home, you should act as quickly as possible, especially to get to the bottom of the cause. Air purifiers can at the same time be an effective measure to stop the spread of mold and protect your own health from the dangerous mold spores in the air. To counteract the unpleasant smells of mold, air purifiers with an additional carbon filter should be used. In general, it can be said that air purifiers not only combat mold spores in the air but also other nuisances such as pollen or animal hair.