A ventilation system ensures the continuous exchange of indoor and outdoor air to ensure good air quality and a pleasant indoor climate in tiny houses and modular houses. It helps remove pollutants, allergens and excess moisture, which prevents mold growth and other moisture problems. Modern ventilation systems, such as controlled living space ventilation (KWL) and heat recovery ventilation (WRG), are often equipped with heat recovery to minimize energy losses and increase energy efficiency. A well-designed ventilation system is crucial for the well-being of the residents and the longevity of the building.