Exhaust air and send it through a heat exchanger, which then literally heats the cold fresh air with the warm one and then feeds it to the sauna, at 40°C to 55°C instead of around 20°C, for example, which then flows into the room. The energy then required to reach 80°C, for example, is then significantly lower than before. The warm air can also be used to heat up other areas of the wellness facility. The same system configuration is available here, with the one difference that the warmed-up fresh air is routed to distant areas via pipes and ventilation ducts. The air flows can be regulated with many individual fans or with control flaps. Modular designs can significantly reduce costs, but only really make sense for large systems. The controls of the ventilation systems can also be managed or controlled via displays or remote access, talk to us.