Influence of ventilation systems on indoor air quality

Controlled ventilation is essential to maintain a healthy indoor climate. Depending on the situation, i.e. if hygienic air quality cannot be achieved through natural or manual ventilation, it may be advisable to install an air conditioner or ventilation system. Regular maintenance is imperative.

In particularly airtight buildings, a sufficient minimum air exchange rate and consequently healthy indoor air quality can only be achieved with technical support, such as the additional installation of a controlled ventilation system with heat recovery However, good indoor air quality can only be maintained for many years through professional planning and installation of suitable systems. Regular cleaning and maintenance are also important for the long-term functional reliability of such systems. Otherwise, there is a risk of odors or even foreign substances forming due to chemical reactions on surfaces of the system. This can lead to poor or even unhealthy indoor air quality.

Important aspects when operating an air conditioning and ventilation system

Air conditioning systems should cool and heat the room air independently of external and internal influences, ensure air exchange (air renewal) and clean, humidify and dehumidify the air. In contrast to a full air conditioning system, partial air conditioning only fulfills certain of the above requirements. Air purification can be achieved by installing suitable filters that keep out dust contaminants and unwanted outside air.

When installing an air conditioning or ventilation system, in addition to the structural requirements and acquisition costs, the follow-up and maintenance costs must always be taken into account during the planning stage.  Improperly maintained systems not only lead to increased energy consumption, but also pose a health risk. If regular maintenance and cleaning of the system is neglected, there is a risk of soiling and microbiological contamination. Microorganisms (bacteria, mold) can colonize in the condensation water and cause hygiene problems, especially when the fresh air supplied is conditioned. The corresponding contamination negatively affects indoor air quality and can also lead to unpleasant odors. The selection and design of the filters should be professionally planned in accordance with the use and hygiene requirements. Incorrectly calculated or incorrectly installed filters that do not sufficiently clean the incoming fresh air can also lead to a reduction in indoor air quality.

In Germany, the DIN 1946-6:2019-12 standard describes the rules for the ventilation of new buildings and renovated old buildings as well as the requirements for ventilation concepts. The standard DIN EN 16798-3:2017-11 covers the planning, construction and operation of ventilation systems in non-residential buildings intended for human occupancy.

• DIN 1946-6:2019-12 Raumlufttechnik - Teil 6: Lüftung von Wohnungen - Allgemeine Anforderungen, Anforderungen an die Auslegung, Ausführung, Inbetriebnahme und Übergabe sowie Instandhaltung
• DIN EN 16798-3:2017-11 Energetische Bewertung von Gebäuden - Lüftung von Gebäuden - Teil 3: Lüftung von Nichtwohngebäuden - Leistungsanforderungen an Lüftungs- und Klimaanlagen und Raumkühlsysteme (Module M5-1, M5-4); Deutsche Fassung EN 16798-3:2017
• GEG, 2023. Building Energy Act (Gebäudeenergiegesetz). Federal Gazette. Berlin. https://www.gesetze-im-internet.de/geg/GEG.pdf.
• Künzel, H. (Hrsg.), 2009. Wohnungslüftung und Raumklima. Grundlagen, Ausführungshinweise, Rechtsfragen. Fraunhofer IRB Verlag, Stuttgart.
• Umweltbundesamt (UBA), 2006. Energiesparen in Gebäuden und gute Raumluftqualität sind möglich. Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz 49, 320-321.