Heat recovery ventilation is expected to be a major ventilation solution while energy performance of buildings is improved in Europe. This European guidebook prepared by REHVA and EUROVENT experts includes the latest ventilation technology and knowledge about the ventilation system performance, intended to be used by HVAC designers, consultants, contractors, and other practitioners. The authors of this guidebook have tried to include all information and calculation bases needed to design, size, install, commission and maintain heat recovery ventilation properly.