Why is so important that we ventilate correctly?
If you ventilate the wrong way, damp spots and moist places will start to form rather quickly in areas near windows and external walls of your living space.They are black in color and are far from being healthy, as it happens to be a type of mould called „Aspergillus-niger". This mould will emit spores, that once they are inhaled by humans, will most likely cause serious chronic pulmonary diseases.
What is the reason that damp spots and areas emerge in a living space?
Cold air is able to store less humidity than warm air is capable of doing so. If there happen to be colder areas within a living space, air that is saturated with water vapor, will always set free water. At first there will be the emergence of wet patches and then soon followed by the infamous black ones.
Where does the moisture originate from?
Where people are living, all kinds of activities take place that add moisture to the existent air. It is being cooked, showers are taken, moist towels are hanged up. But also a washing machine. Every human dispenses via exhaling an estimated 1,5 litres of water per day. All these sources combined, form the water vapour within the air around us.
How are we able to regulate the amount of moisture, so that we can avoid the emergence of the black disease causing patches?
Colder air is able to store less moisture than warm air.
It has to be taken care of that the warmed up air in a living space is exchanged for cool air from outside. Ventilation has to take place. Imagine the following figuratively: When ventilating, between one and two buckets of water are being transported together with the warmed up air from inside to outdoors. The air is exchanged for fresh air from outside, that has stored less humidity eg. less water. Once inside, the colder air is slowly warmed up by people, walls, furniture, appliances and as such is able to store more moisture. Ventilating again, takes care of another two buckets of water and the cycle repeats itself. Ventilating this way makes sure that a living space remains sufficiently dry and moist spots do normally not occur.
How to ventilate correctly?
It is highly recommended to ventilate every 4. hours. In doing so, it means to open up the windows wide, and it has to be ensured that passage is achieved. So open the windows and doors in as many rooms as possible and after approximately 5-10 minutes the warm moist air is exchanged with the cooler dry one from outside. Moisture has then left the living space.
Continuous ventilating, however, has the effect that the air cannot be heated up properly within the house. In the areas around the open windows, colder spots will start to appear than in the rest of the living space. This colder air can hardly be heated up and as such is able to store less moisture.
But as the moisture is still present, it will adhere to the colder areas around the windows and outer ceilings. As a result you will have the dreaded black mould spots in no time at all!
Shortly before going to sleep you should ventilate intensively. If you leave your windows open during the night, it will be the cause not only the issues described before, but also your bed linens will become moist. Now moist bed linen creates the next ideal habitat for house dust mites. The excrements of these small dust mites are equally to cause severe pulmonary diseases. So take care that you are ventilating thoroughly on a regular basis, then completely close the windows again for at least 4.hours and that you do so for a minimum of 4. times a day.
This type of ventilating a living space is called "Stoßlüften" in Germany. Perhaps best translated by calling it "ventilating intensively" as there is no english word for "Stosslueften".
Continuously ventilating has to be absolutely avoided, as it is a serious health hazard!