{"id":997610,"date":"2026-10-06T08:00:00","date_gmt":"2026-10-06T06:00:00","guid":{"rendered":"https:\/\/kienzler-klima.de\/?p=997610"},"modified":"2026-08-19T11:26:48","modified_gmt":"2026-08-19T09:26:48","slug":"how-draft-free-ventilation-affects-childrens-concentration-in-school","status":"publish","type":"post","link":"https:\/\/kienzler-klima.de\/en\/how-draft-free-ventilation-affects-childrens-concentration-in-school\/","title":{"rendered":"How does draught-free ventilation affect children’s concentration at school?"},"content":{"rendered":"
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Draft-free ventilation has been proven to improve children’s concentration at school by keeping CO2 levels in the classroom permanently low without generating disruptive drafts. High CO2 concentrations lead to fatigue, headaches, and loss of concentration \u2014 factors that directly impair learning outcomes. The following sections shed light on the most important questions surrounding air quality, ventilation technology, and the selection of the right system for school buildings.<\/p>\n

Why does poor indoor air quality impair children’s learning performance?<\/h2>\n

Poor indoor air quality impairs children’s learning performance because rising CO2 levels in the classroom directly reduce cognitive performance. At CO2 levels as low as 1,000 ppm, students more frequently report headaches, drowsiness, and concentration problems. In poorly ventilated classrooms, these levels are often significantly exceeded during lessons.<\/p>\n

A classroom with 25 to 30 children generates a considerable pollutant and heat load through exhaled air, body heat, and activity. Without adequate air exchange, not only CO2 but also moisture, odors, and volatile organic compounds accumulate. The result is indoor air that literally makes children tired, even when the lesson is interesting and well-structured.<\/p>\n

Particularly problematic: children are less likely to consciously perceive poor air quality than adults. They respond with lack of concentration and restlessness, without being able to identify the cause. Teachers and parents then often attribute fluctuations in performance to other causes, even though indoor air quality in the classroom is a central, highly manageable factor.<\/p>\n

What is meant by draft-free ventilation in school buildings?<\/h2>\n

Draft-free ventilation in school buildings refers to a ventilation principle in which fresh air is introduced into the room evenly at a very low discharge velocity, so that no perceptible air movements reach the occupants. The goal is continuous air exchange without the unpleasant sensation of drafts that frequently occurs with conventional ventilation outlets.<\/p>\n

Conventional ventilation nozzles or slot diffusers blow air into the room at comparatively high velocities. This leads to local cold zones and draft sensations that are perceived as particularly disruptive by children and can cause complaints. Draft-free systems, by contrast, distribute air over a large area at low flow velocities, so that fresh air mixes gently with the room air.<\/p>\n

In practice, draft-free ventilation in schools is frequently realized through textile air distribution systems<\/a> that discharge air evenly across the entire permeable surface of the duct system. This technology is particularly well suited to spaces where people sit for extended periods and are sensitive to temperature fluctuations or air movements.<\/p>\n

How do textile and conventional ventilation systems in schools differ?<\/h2>\n

Textile ventilation systems differ from conventional sheet metal duct systems primarily in the way air is discharged, installation costs, and ease of maintenance. While sheet metal systems blow air into the room at specific points via outlets, textile systems discharge air evenly across the entire duct length, with significantly lower discharge velocities and therefore without any draft sensation.<\/p>\n

Cost comparison and installation effort<\/h3>\n

Textile air distribution systems enable savings of up to 60% on material and installation costs compared to conventional sheet metal systems. This is due to simpler assembly, lower weight, and faster installation. For school buildings, which often operate under limited renovation budgets, this is a relevant factor.<\/p>\n

Hygiene and cleaning<\/h3>\n

Another difference lies in the area of hygiene. Textile ducts can generally be fully dismantled and machine-washed, which greatly simplifies cleaning. Sheet metal ducts, by contrast, are complex to clean and difficult to access. For schools where hygiene requirements are taken particularly seriously, this is a practical advantage. An overview of textile ventilation products<\/a> for various applications can be found in the product overview.<\/p>\n

What indoor air quality standards are legally required in classrooms?<\/h2>\n

In Germany, there is no uniform federal regulation prescribing binding CO2 limit values for classrooms. However, the recommendation of the Federal Environment Agency serves as a recognized benchmark: a CO2 level below 1,000 ppm is considered hygienically acceptable, while values between 1,000 and 2,000 ppm are classified as elevated and require ventilation measures.<\/p>\n

DIN EN 16798 and VDI 6022 define requirements for air-conditioning systems and indoor air quality in public buildings. Schools generally fall under Category II or III, corresponding to a medium to low indoor air level. In practice, these requirements are not reliably met by window ventilation alone in most classrooms.<\/p>\n

Some German federal states have issued their own school building guidelines that set requirements for mechanical ventilation or at least for minimum air change rates. Anyone planning or renovating a school building should check the applicable state regulations early on and incorporate them into the planning process.<\/p>\n

When does retrofitting a controlled ventilation system in schools make sense?<\/h2>\n

Retrofitting a controlled ventilation system in schools is worthwhile whenever window ventilation alone cannot ensure adequate indoor air quality \u2014 for example, due to unfavorable building orientation, ambient noise levels, extreme outdoor temperatures, or when CO2 levels in the classroom regularly exceed 1,500 ppm.<\/p>\n

Further indicators for a sensible retrofit include recurring complaints from students or teachers about headaches and fatigue, visible moisture problems or mold growth, as well as school buildings that are being energy-retrofitted and thus becoming more airtight without a controlled ventilation system being planned.<\/p>\n

From an economic perspective, retrofitting is particularly advisable when renovation or conversion work is already planned. Installing a ventilation system at the same time significantly reduces the overall effort. Textile ventilation systems are especially suitable for retrofitting because they are lightweight, require little space, and can be installed quickly. More information on the areas of application for textile ventilation systems<\/a> can be found in the sector overview.<\/p>\n

How is a textile ventilation system designed for a classroom?<\/h2>\n

The design of a textile ventilation system for a classroom is based on several parameters: room size, number of occupants, ceiling height, desired air change rate, and thermal loads from people, equipment, and solar radiation. On this basis, duct diameter, duct length, textile permeability, and the arrangement within the room are calculated.<\/p>\n

For a typical classroom with 30 students, a minimum fresh air supply of approximately 20 to 30 cubic meters per person per hour is recommended to keep CO2 levels permanently below 1,000 ppm. The textile system is dimensioned so that air is distributed evenly across the entire length of the room without creating cold zones or draft sensations.<\/p>\n

The choice of textile material is also crucial: depending on requirements, different permeability grades are available, which determine how much air exits directly through the fabric and how much is directed through nozzles or slots. The combination of both effects enables precise control of air distribution, even in rooms with irregular geometry or special acoustic requirements.<\/p>\n

How Kienzler Klima supports schools with draft-free ventilation<\/h2>\n

We at Kienzler Klima have been developing and manufacturing textile ventilation systems for more than 30 years, with experience from projects in laboratories, industrial halls, food processing facilities, and public buildings. For schools and educational institutions, we offer the following services:<\/p>\n