Your Mold Guide

Guidebook for Humidity & Mold

Most of our time we live in closed rooms. Bedrooms, offices and school buildings are the most used rooms. For this reason, air quality is of great interest!

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Guidebook for Humidity & Mold

Ideal Condition

What influences our well-being?

We spend most of our time indoors. Bedrooms, offices and school buildings are the longest-used rooms. For this reason it is recommended to pay particular attention to a healthy indoor climate. Whether we feel comfortable in a room depends on the building conditions and personal perception of the climatic conditions in the room. Essential factors for a healthy indoor climate are:

  • Room temperature
  • Surface temperature: walls, floors, ceiling, windows
  • Humidity
  • Air circulation
  • Air quality
    • Oxygen content, odors, mold spores,
    • Pollutants, tobacco smoke, cleaning agents,
    • Vacuum cleaners, chemicals, detergents
    • Adhesives from furniture, floors and building materials

With proper ventilation and heating behavior, you can influence these factors in your favor.

However, our feel-good area does not only depend on temperature or humidity, but both factors in a balanced relationship determine the optimal range. If, for example, the walls are cold because of poor outdoor insulation, the air tempe- rature must be higher so that you feel comfortable in the room. In the case of damp, cold air as a permanent condition, rheumatic diseases may occur. A longer lasting humidity reduction of 35% means that the upper and lower airways are affected.

ideal air conditions

Did you know:

Conscious heating and ventilation not only ensures healthy room air, but also helps you save energy! A reduction of the room tem- perature by 1°C lowers the heating costs by about 6 percent. In concrete terms this means: reduce the room temperature from 24°C to 20°C and save between 20 and 25 percent heating costs.

Where Does High Humidity Come From?

What actually causes the humidity?

Just by breathing, the human body releases water into the air. In addition, moisture comes from cooking, bathing, showering, drying, etc. A family of four produces an average of 10 liters of water every day.

Human 1 to 1,5 liters
Cooking 0,5 to 1 liters
Laundry drying 1 to 1,5 liters
Showers 0,5 to 1 liters
Potted Plants 0,5 to 1 liters

In order to transport 10 liters of water from interior spaces, several cubic meters of air must be moved daily. In addition there is the residual building moisture in new buildings. For reasons of cost and time, these days, the building shell is not allowed to dry out during the winter. In addition, some coatings on walls significantly retard the drying process (e.g., resin dispersion paint).


Do not use wallpaper, but a diffused wall paint. Let us advise you in your color shop or DIY store. Preheat more at the beginning and ventilate frequently during the day. Do not place your furniture directly against a wall, keep a distance of approx. 5-10cm.

Reduction of Natural Air for Dense Windows and Doors

High-density windows and doors are advantageous in several respects: they save energy and prevent train phenomena. The cost of heating and energy saving is well developed by many residential users. Save money and also save the air!

Unfortunately, it is not so easy:

As a negative companion of dense windows and doors today there is an increasing amount of moisture and consequently the formation of molds in new buildings or refurbishments. The concentration of harmful or at least critical air gasses (carbon dioxide, formaldehyde ...) in the room air is also significantly increasing. Nowadays, the hygienically necessary minimum air change must be achieved by manual ventilation. What used to be done automatically by leaking joints, so to speak, now being carried out by every housing user on new windows.

If you do not use proper ventilation, you can risk your health due to bad air and the risk of mold formation, as the generated air humidity remains in the room.

Air Stores a Limited Amount of Moisture

Air can only absorb a certain amount of invisible water vapor. If this value is excee- ded, the excess water vapor is released to the environment. In nature, it begins to rain, at home, for example, the mirror in the bathroom, the window in the bedroom, etc.

On humid summers and tropical climates you notice it especially: air feels quite warm and moist. And if you order a cool drink to cool down, the glass is fogged. But why is it like that?

Why is there Fog on my Windows?

If warm ambient air with a high water vapor content hits on a cold drink or a wall, the air cools in this region and consequently cannot store as much water vapor. The excess moisture in the air has to be added to the environment, i.e. to your glass, your walls, your furniture, ect.

What Happens with Humidity?

Danger of mold contamination for walls, furniture ect.

In the case of glasses and mirrors, this effect becomes visible through the fogging of your glass, or penetrates the moisture in walls, furniture ect. It may be that you do not notice this immediately because it is not as obvious in the mirror. However, if this condition persists over a long period of time, mold fungi can grow!

Cold walls - a problem in three ways

If, for example, the walls are cold due to poor external insulation, the air temperature must be higher so that you feel comfortable in the room and the wall temperature is warmed on the other hand to prevent possible condensation on the wall and the risk of mold formation as a consequence of the condensation. They compensate for poor outdoor insulation and the risk of mold attack by increasing heating, thus con- suming more energy.

Do not let it get that far!

How Do I Solve the problem?

How do I get moisture out of the room?

Air can absorb different amounts of water vapor depending on the temperature. Cool air absorbs less water vapor than warm air.

Fresh air in - heat up - and re-airing

Cold outside air, which gets into the room when it is ventilated, heats up and can therefore absorb more air humidity. In order to remove as much moisture as possible from the room, you should therefore ventilate frequently during the day.

How do I know how high the humidity is outside?

You can display the humidity for a certain location on the Internet on various portals. It is easier and more convenient to use the bluSensor AIR ventilation app. This is available free of charge and shows the outside humidity at your location. If you also know your indoor humidity the app can calculate if it is a good time to air your room.

Insecure - measure your values in the interior!

If you are on the safe side for health reasons or to prevent mold, you should check your room ventilation. To match the bluSensor AIR ventilation app, there is a bluSensor measuring device, which is integrated into the app and automatically takes into account the air humidity in the interior during the ventilation calculation - without having to manually enter indoor humidity values. In addition, you can analyze your room climate comfortably, precisely and simply by means of long-term recordings and automatic alarm function, and improve your ventilatory behavior accordingly

How Do I Ventilate?

Proper heating and ventilation, especially in „airtight“ buildings, is all the more important nowadays.

In order to maintain a healthy indoor climate with sufficient oxygen and optimum air humidity, fresh air must enter the room from outside. You have to ventilate and indeed ventilate. As short as possible - to save energy - but nevertheless long enough - to achieve an effective air exchange.

Sufficient air exchange is the basis for a living climate.

The advantages of proper ventilation are:
  • Reduction of excess humidity
  • Reduction of harmful substances and odors
  • Walls and furniture remain warm

Quick or cross-ventilation is the best type of window ventilation!

Our app bluSensor AIR helps you to find the right time for airing your room.

Cross 2 - 5 minutes Wide open and transversal windows
Quick 5 - 10 minutes Fully open window - opposite door closed.

The duration of the ventilation in order to achieve air exchange is strongly dependent on the outside temperature. The colder it is outside, the shorter you have to air.

Fist rule - How often should I air?

Air 2 to 4 times daily, depending on how much you are in the rooms.


The bluSensor AIR App, in the free version, has an integrated timer that calculates the optimal ventilation time depending on the outside temperature and humidity, and alerts you when this time has elapsed so you do not waste unnecessary heating costs.

Why not tilt the windows?

Make it a habit immediately ventilating the room after showering, bathing, cooking or floor washing. Thus the humid air reaches the outside best, does not enter into furniture and walls and does not spread in the other rooms.

Instant airing is by far the most effective!

Make it a habit immediately after showering, bathing, cooking or floor washing to ventilate and before using the rooms to close the doors. These should be opened again only after the ventilating process. Thus the humid air reaches the outside best, does not enter into furniture and walls and does not spread in the other rooms.

By the way:
If the outside air is cold, you can also vent it in rainy weather, as the air in the room is heated and moisture can be absorbed from the room.

After getting up, you will be able to ventilate your bedroom. This makes you fit for the day and distributes the moisture that has accumulated over night in the air, furniture and plaster. Before sleep, you must ventilate again to reduce the carbon dioxide in the room to a minimum. This ensures a good night rest.

Additionally, in the bathroom

In the bathroom after showering, the water from walls and floors should be dried. Wet towels should be dried as quickly as possible on the radiator. For bathrooms without windows, a shaft vent should be installed.
Note: Did you know that the exhaust ventilator in the bathroom and toilet only works properly when fresh air enters the apartment at the same time? A corresponding negative pressure must be generated for proper operation of the fan.

Switch on the cooker hood during cooking!

Use a fume extractor in the kitchen with exhaust air to the outside. Such a trigger helps to remove a lot of moisture that is produced during cooking.

Doors close helps!

Do not leave too little heated rooms or rooms with a lot of moisture, so that the humidity does not spread throughout the home.

Little heated rooms

Less heated rooms (e.g., bedrooms) should not be warmed by warm air from adjacent rooms. Warm air enters the room, cools down, and condensation can occur on walls or window panes. Therfore always close doors to colder rooms.

Airing in summer

The right time to air in the summer is early in the morning or later in the evening, when the outside temperature is cool. During the day, windows and doors should be closed as far as possible.

Attention - Ventilation in the basement

The basement should be ventilated in the summer as little as possible, and then only in the cool morning hours, otherwise warm air hits cold cellar walls and furniture and condenses and there is the risk of mold formation. False airing in summer is the main cause of damp cellars.

Airing in the case of prolonged absence

Avoid leaving your windows open during the heating period in a permanent tipping position, since condensed water forms on cooled areas in the room. Heating energy is also lost. In the summer months, however, this is no problem. Note, however, that this is not a substitute for a proper air vent.


Apart from humidity and temperature, bluSensor AIR also shows the dew point. You can position it in exposed places and often ask for your air climate - wireless and convenient, without having to move furniture.

Mold Prevention

Mold fungi occur everywhere. However, if the mold concentration exceeds a certain value, it can lead to health problems, especially airway complaints. Spores and metabolic products of molds enter the room air, are inhaled and can trigger allergic and irritating reactions in humans.

The cause of mold is always increased moisture.

Preventive Measures against Mold

Proper ventilation reduces the humidity in indoor areas and thus prevents mold infestation.

Reduce moisture emission
  • Do not dry laundry in rooms.
  • Close doors to rooms with high humidity (showers, cooking, ironing etc.) and ventilate properly after use.
  • Reduce the number of indoor plants. They evaporate the water with which they were poured.
  • Always cover aquariums.
  • Avoid the dryer.
Leave room corners free

Do not place furniture in a room corners, as these are particularly vulnerable. Air circulation must be possible at critical points.

Do not place the furniture directly on the wall

Do not place your furniture directly on exterior walls. By a distance of 5-10 cm a residual circulation of air can be achieved.

Hang pictures with Space

Also make sure you have a residual circulation behind the pictures.

Select the appropriate wall surface

Avoid wallpapers, dispersion paint or glue paint and use mineral lime and silicate paints instead. Diffusion-free wall cladding is better than sealing a wall with paints.

More heating - should be the last resort

By increasing the temperature, the air can absorb more moisture. Using selective ventilation and heating, more air humidity can be removed from the room.

If you need to wash laundry in the apartment, you should leave the room door closed and then ventilate at short intervals.

Close doorts to cold rooms

Do not allow humid air to enter specially endangered rooms.

Initial moldy odor

Molds develop in secret. At first a modest, musty smell is perceptible. In the growth phase, molds form cell filaments, which are mostly colorless and are not recognizable with the naked eye.

First visible black spots or dots

For growth, molds form so-called spores, which are recognizable in color as black or yellow mold lids.

Surface mold

The mold spreads further and there is no longer any doubt about the infestation.

Attention - mold is also created in secret

It is more difficult to detect mold cavities in cavities behind moldings, ceilings or walls. If you suspect this, please consult a specialist. Increasingly, specially trained tracking dogs are used to sniff out hidden mold contamination. This can be helpful if you do not know exactly where your mold has been hidden and you do not want to dismantle all the moldings on suspicion.

Remediation of Mold

Important - Eliminate the cause

Before you begin with a mold remedy, the causes of the mold fungus must be investigated. This is the only way to ensure that the mold does not come back. Elevated humidity can have two causes:

  • Damage or damage to the building site or
  • Wrong behavior of the space users.

Disputes - Who is to blame?

In the case of new buildings, there are often disputes between developers and owners, who mutually accuse each other of deficiencies or wrong housing behavior. In the case of tenancy, mold is often the subject of discord, who is to blame for the mold, which often end in court and have to be decided upon after consulting an expert. House administrations usually assume that tenants ventilate too little.

Absolutely exclude wrong living behavior

No matter whether you are discussing with the tenant, landlord or property developer about who's to blame or not, and before proving the damage caused by the customer, you should check your own living habits for correctness. To admit mistakes here is still the easiest and„most cost-effective“ way to eliminate mold causes. Confirming that your ventilation and heating behavior is correct also confirms you in the further clarification of the causes.

Improperly ventilated - refurbish even smaller molds

If there are no deficiencies in the structure the mold attack is minor, i. e. not more than half a squaremeter, and you are not suffering from allergic or chronic respiratory diseases, and you do not have a weakened immune system. Otherwise, you should consult specialist personnel.


Buy a measuring device that allows you to control and record your living habits. Learn to vent with the ventilation app properly and ensure. If molds nevertheless occur, you can contact a specialist with the recorded values and investigate other causes for the mold.

Tips for Remedial

Low dust works

Avoid excessive amounts of fungal spores entering the room air. Instead of wiping dry areas, use a damp cloth. Do not sweep floors with brooms!

Use a vacuum cleaner
  • with special fine dust filters (HEPA filter)
  • with tested housing gasket (allergy vacuum cleaner).
Conventional vacuum cleaners swirl the spores into your breathing air. If you want to be on the safe side, buy a dust mask or sunglasses for your DIY store. Use gloves

Do not touch mold with bare hand.


For cleaning and disinfecting, e.g. 70% for dry surfaces and 80% for humidified ethyl alcohol. Cleaning rags must be disposed of properly - fire hazard of concentrated alcohol. Before use of vinegar is advised: with the vinegar, organic nutrients reach the materials, which promote mushrooming. In addition, many building materials, especially lime, neutralize vinegar.

Beware of chemical fungi

These active ingredients remain in the indoor areas for an extended period of time and it can not be ruled out that these active substances endanger the health of the inhabitants. Should you use these nevertheless, you must ventilate often and cor- rectly.

Clean thoroughly

The goal must be to completely remove molds. What you cannot clean should be disposed of. Especially for upholstery, carpets or wallpaper, which cannot be completely cleaned, the overcoming is great for many to throw away. Also, the plaster from the wall knock off is for many a large inhibition threshold. But please bear in mind: even killed mushrooms can cause health problems!

Mold infestation on smooth surfaces

Furniture flow, ceramics, glass ect. moisten with household cleaner and rehabilitate as described above.

Mold infestation on smooth surfaces

Any furniture with a closed surface (chairs, tables, cabinets) should be cleaned as described above.

Mold infestation on upholstery

Highly impacted upholstery can only be rehabilitated with considerable effort and should therefore be disposed of.

Mold infestation of textiles

House textiles (carpets, curtains) are also to be cleaned only with great effort appropriately. A new purchase is usually the more cost-effective variant.

Mold infestation in silicone joints

Silicone joints should be completely removed and replaced with a special sanitary silicone (by specialist company).

Mold infestation on porous materials

Wallpaper, plasterboard boards, porous masonry and ceiling claddings can be difficult or impossible to clean, as the pilots penetrate deep into the material.

After completion

Pack the contaminated wastes in plastic bags. As a conclusion, you should also thoroughly wash and shower your clothes.