Good air for good spirits

LWE-W 115 Plus ventilation units ensure a regular supply of fresh air

Advanced ventilation system creates comfortable room climate

The old farmhouse has undergone a number of minor renovations over the years. But patches of mould persisted due to a lack of sealing and ventilation. These are now a thing of the past: thanks to an advanced ventilation system, continuous ventilation is guaranteed and the room climate has been significantly improved.

Densbüren ventilation system


  • Old farmhouse
  • Regular renovations
  • Persistent mould problems
  • Ventilation systems offer considerably more convenient ventilation


  • 5026 Densbüren, Switzerland

Installed appliances:

  • 4 x LWE-W 115 Plus


  • Reto Hürlimann, Kissling Gebäudeplanung GmbH, 5035 Unterentfelden

Mould no match for ventilation systems

“Despite regular renovations, mould remained an issue in recent years,” explains Reto Hürlimann, owner of the six-and-a-half-room farmhouse. Moisture penetrates the 60 to 70 cm of masonry by means of capillary action. In addition, half of the basement level is underground. “We wanted the ventilation system to improve the exchange of air, which has been successful,” adds Hürlimann. The need for manual ventilation has been significantly reduced thanks to the ventilation units installed in various rooms. “We can also cross-ventilate for very rapid air exchange. This is especially helpful when dealing with strong odours, for example after a delicious fondue,” explains Hürlimann.

Fresh air thanks to ventilation units

“It’s important to get the siting right when planning a ventilation system,” explains Stefan Schürmann, a consultant for engineers and architects at STIEBEL ELTRON. “That’s not always an easy undertaking with an existing building.” One reason is the increased difficulty of installing the ventilation pipes required for a central system during modernisation. This and other considerations meant that reversible fans were the ideal solution for the Densbüren farmhouse, given that a central unit was entirely out of the question for this property. The design is also key to ensuring a system is correctly sized and matched to the air volume in the rooms.

Once such problems have been solved in theory, there should be no further impediment to the practical implementation. “The installation itself is actually really straightforward,” continues the owner. He happens to be an expert in the field, but even so, the timeline speaks for itself: “It only took us a few days to get everything installed.” And once the unit is up and running, the improved air quality is clearly noticeable. “We know this from experience and can confirm it through measurements,” affirms Oliver Joss, a technical sales engineer at STIEBEL ELTRON. An air quality sensor integrated into the ventilation system continuously monitors the CO2 content in the air and controls the ventilation accordingly.

LWE-W 115 Plus decentralised ventilation unit

Thanks to its ease of installation, the LWE-W 115 Plus decentralised ventilation unit is particularly suitable for both new build and modernisation projects. It is installed in square wall outlets. The electrical connection on the inside of the fan unit is very straightforward and easily accessible. The AC fan ensures optimised, quiet operation. As the axial fan can overcome back-pressure, it is also suitable for use in locations exposed to the wind. The ventilation unit can be mounted directly to the façade as the external panel is watertight against heavy rain. The efficient aluminium heat exchanger ensures that heat recovery is possible. The pollen filter cleans the incoming air, making it ideal for allergy sufferers.

This is also confirmed by the owner, who could not be happier with the solution. “Our experiences to date have really been very positive,” says Hürlimann. “The reversible fans save us having to ventilate manually. The mould issue has been eliminated and in general we’re enjoying a better quality of air.”

Project information

This project stands out because it involved finding an easy-to-install and space saving solution for an advanced mechanical ventilation system in an old residential building.

The biggest challenge lay in cleanly accommodating all of the power cables in cable ducts and routing them to a central point for the control unit.

The straightforward installation of the decentralised ventilation units, efficient heat recovery and quiet operation of the equipment are especially noteworthy.

The consistently excellent air quality in the building is the most pleasing aspect. In addition, draughts are no longer a problem and mould issues are a thing of the past.

Technology used: LWE-W 115 Plus

  • Decentralised ventilation unit with heat recovery for new build and modernisation
  • Compact fan unit enables rapid filter change and visual inspection of the heat exchanger without tools
  • No run marks on the wall face thanks to deflection of condensate away from the masonry
  • Quiet operation
  • Aluminium heat exchanger permits particularly quick and hygienic cleaning
  • High moisture recovery through aluminium heat exchanger