Renovate for comfort, air quality and above all energy efficiency. In that context, the difference between a classic C system (mechanical extraction + supply via window grilles) and a D system with heat recovery (WTW) large-certainly if you opt for decentralized devices per room.

For years, a central system the "logical" choice: complete, with ducts throughout the house. Decentralized systems used to have a reputation for more noise and less heat recovery. Those days are over. Modern decentralized units are quiet, energy-efficient and finely adjustable per room - exactly what you want in renovations and often also in new construction.

We all know by now: poor indoor air makes learning more difficult and makes a school more vulnerable to waves of illness. This is not a retrospective, but an action plan for now. With decentralized ventilation you pack per room what is needed-without a big yard sale, and without waiting until the next vacation.

Keeping your building healthy is not a nice-to-have. It is value retention, fewer complaints and peace of mind. In blocks with many resident profiles (smokers/non-smokers, many-cooks/little-cooks, care residents), a central system often reaches its limits in practice. The solution that does work in renovated and occupied buildings: decentralized D-ventilation per apartment/room..

Open windows in spring? Lovely. But windows open is not a ventilation strategy. It's unpredictable (wind, noise, pollen, safety) and stops as soon as it's too hot/cold or too crowded outside. Meanwhile, CO₂, odors and volatile compounds (VOCs) accumulate - and you feel it in your head, your energy and your productivity.