Which components affect our indoor climate

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Dataloggers measure the room climate

Introduction – The climatology is one of the most difficult areas of science. Air, temperature and electric climate influence each other more or less – and these factors are in turn influenced indoors of building materials, construction and electrical installation. Although cooperating the individual components of indoor climate, it will be discussed for better presentation separately. Now read which components affect our indoor climate.

Fresh air Quality

The clean air is about 78% nitrogen, 21% oxygen and 1% inert gases and carbon dioxide (CO2). Measurable is the air quality for building biologists based on the CO2 content. In the wild, the CO2 content is below 400 ppm. After a complete air exchange should prevail inside and outside the same conditions in about. With the windows closed and in a large number of people in the room, the CO2 content rises. In a classroom, values show, for example, after an hour of teaching larger 2,000 ppm. An important control variable for good air quality, the air exchange rate. The ratio of “1” indicates that, once an hour takes place an exchange of air. A value of 0.25 indicates that the exchange of air takes place only every four hours, etc.

Ratio of room temperature and surface temperature

The surrounding surfaces of the rooms, that is Floors, walls and ceilings should have the same temperature as the air. Air movement affects the temperature to be at ease. A difference between surface and room air temperature of 2°C causes an air movement of 20 cm/s. The optimum air flow is 10 cm/s.
Relatively high surface temperatures are achieved by radiant heat. Apart from the direct sunlight heating by wall heaters or stoves can be achieved. The outflow of the stored heat must be prevented. This requires the following measures: windtight building envelope, uniform insulation, high Quality windows and professional installation, low moisture content, avoidance of technical thermal bridges.
A sufficiently high surface temperature prevents condensation, which are regarded as a breeding ground for mold and fungus formation. As a benchmark the relationship between ambient temperature and surface temperature. The difference in temperature, even at unfavorable locations such as corners, must never be more than 8 ° C, otherwise condensation and then mold forms.

The importance of indoor air humidity

The optimal relative humidity is between 40% and 60% and is in the relationship between the ambient temperature and the absolute humidity. The absolute humidity is the actual amount of water in grams in the air. The maximum humidity, the temperature-dependent maximum intake is referred to in grams. Two examples: a room can accommodate per cubic meter at 20°C. 17.3 g of water at 25°C room temperature, there are 23.1 g/m³. With a volume of 50 cubic meters (20 m2 * 2.50 m) and 20 ° C ambient temperature the air contains a maximum of 865 g of water, at 50% humidity there are 432 g of water.

Find a good balance

A relative humidity less than 30% has the following disadvantages: The dust content increases. Electrostatically charged room surfaces ensure an extremely one-sided positively ionized air. A relative humidity over 70% leads to mold growth, bacteria, viruses and dust mites. The relative humidity should be regularly checked with a Hygrometer.

The impact of construction materials on the indoor climate

From a building biology perspective building materials are to set high standards in the interior of. They should have especially in the floor area of a high surface temperature. Important for the indoor climate is also the ability to absorb water vapor rapidly and slowly release it again into the ambient air (hygroscopic). Diffusible materials allow the exchange of gases in the concentration gradient between indoor and outdoor air. Last but not least should make the materials themselves no toxic gases and vapors. Wood and clay are natural materials which meet the above characteristics very well. They also have an excellent energy balance.

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