The Helios Fans KWL-ET 250 is a high-performance enthalpy heat exchanger designed for retrofitting into ventilation systems. Utilizing a large-area cross-counterflow design and made from advanced polymer membrane foil, it enables simultaneous recovery of heat and moisture. This results in a comfortable and healthy indoor environment across all seasons. With its hygienic operation and efficient energy use, the KWL-ET 250 is ideal for enhancing the performance of existing ventilation units by improving indoor air quality and reducing energy loss