Function principle

How the Zehnder ComfoFresh air distribution system works

Zehnder ComfoFresh air distribution systems bring fresh air to all rooms and simultaneously remove stale, moist, contaminated air and odours. Air is exchanged without draughts and bothersome noises, at the highest possible efficiency, thanks to displacement ventilation. The air volume can be individually adjusted. Zehnder ComfoFresh comes in the OnFloor (on the unfinished floor) and InFloor (in the unfinished floor) installation models.


  • The air distribution system ensures that the fresh air reaches the individual rooms and the extract air is simultaneously removed outside.
  • This is done by means of air ducts that can be controlled separately.
  • The only visible elements of the system, aside from the controller, are the designer grilles, which hide the supply and extract air outlets.

Supply and extract air

  • Supply and extract air rooms are differentiated when ventilating homes.
  • Rooms such as living rooms, bedrooms and children’s rooms are known as supply air rooms.
  • Extract air rooms are rooms from which steam and odours are removed, such as the kitchen, bathroom and WC.
  • When the ventilation solution is designed, the arrangement of the supply and extract air openings is arranged so as to ensure cross ventilation through the building.

Sound insulation

  • Supply and extract air ducts are fitted with attenuators to keep air distribution as quiet as possible.
  • Because each air vent is individually connected to the manifold, noise transmission from room to room is not possible.
  • This guarantees almost noiseless air distribution to the separate rooms.

Zehnder OnFloor and InFloor – effective and hygienic

OnFloor air distribution (on the unfinished floor)

  • Oval, flexible flat tube (51 mm) – easy to install
  • High-quality food-grade plastic (HDPE)
  • Clinside smooth inner skin for clean tubes
  • Centrally and decentrally adjustable airflow rates
  • Low pressure losses
  • Easy to clean
  • SKZ-certified

InFloor air distribution (in the unfinished floor)

  • Flexible round tube – easy to install
  • High-quality food grade plastic (HDPE)
  • Clinside smooth inner skin for clean tubes
  • Centrally and decentrally adjustable airflow rates
  • Low pressure losses
  • Easy to clean
  • SKZ-certified

What to consider in the context of air distribution

  • Space requirement: A space-saving installation of the air distribution system takes up as little living space as possible and saves space for other technology. Zehnder has developed clever products for this purpose: Zehnder ComfoWell, the modular system for attenuators, filters and distribution manifolds, takes up very little installation space, for example. A cross-piece enables pipes to be crossed without taking up additional space. The height remains at just 50 mm instead of 120 mm.
  • Planning & installation: Unlike many providers, Zehnder will plan and lay out the complete ventilation system with a view to achieving optimum energy efficiency and best possible sound values at every stage. As a result of products that are optimised for installation and self-explanatory, installation work can be kept relatively low, saving you valuable time and your customer money.
  • Attenuation: Zehnder ventilation units deliver very good sound values as standard. They are achieved with the assistance of a well-matched air distribution system. Sound values during operation are reduced still further by optimum installation and the selection of the right components (e.g. attenuators). Zehnder ComfoTube ventilation tubes, for example, feature Clinside smooth inner skin to reduce air resistance. The unit can be operated at a lower setting and sound is reduced to a minimum.
  • Comfort & health: Good ventilation systems are easy to use, quiet during operation and never cause draughts. A system for comfortable indoor ventilation from Zehnder meets all of these requirements for user comfort and convenience.
  • Maintenance & hygiene: Zehnder makes sure that the products arrive on site in a hygienically flawless condition. The grille housings, for example, have cover caps that are not removed until after installation is complete. This ensures that dirt from the building site cannot get into the tubes. Furthermore, all relevant parts feature inspection openings which make it easy to carry out checks. The ventilation system will thus remain hygienically flawless for many years to come.
  • Design: Although ventilation units are usually positioned in cellars, in addition to the control panel there are also outlets for supply air and extract air in the living areas. Zehnder designer grilles in various models discreetly conceal these outlets, blending in perfectly with the décor of the living space.