Frischluft

Frischluft is the German term for fresh air. In building science and public health, it refers to outdoor air that is introduced into indoor spaces to dilute indoor pollutants and odors, improving air quality and comfort.

Fresh air can enter naturally through openings such as windows and vents, or be supplied by mechanical ventilation systems. Ventilation rates are quantified as air changes per hour or as volume flow per person or area, and may include heat recovery to preserve energy. A balance between fresh air and recirculated air affects energy use and pollutant control.

Indoor air quality depends on the amount of fresh air as well as the presence of pollutants from occupants, materials, and activities. Adequate fresh air lowers concentrations of carbon dioxide, VOCs, particulate matter, and moisture, aiding health and cognitive performance. Poor ventilation can cause odors, dampness, mold growth, and higher transmission risk for airborne diseases.

Standards and guidelines for Frischluft cover ventilation design, operation, and system hygiene. International and national references include WHO indoor air quality guidelines and European standards such as EN 16798-1; German DIN 1946-6 and VDI 6022 for hygienic HVAC systems. Energy efficiency programs influence how fresh air is supplied, often via demand-controlled or heat-recovery ventilation.