We can name frequent mistakes of clients:- customers in Ukraine try to save on air ducts and their number. However, due to the smaller cross-section of the air ducts, acoustic noise and whistling can be heard in them, which can be heard through diffusers or vents.- customers want to buy the supply and exhaust installation with heat recovery without heating element, a preheater and other automatic equipment at ventilation company in Kyiv. This is fundamentally incorrect, as, for example, at -2 ° C the recuperator in air defense freezes. Certain heat exchangers always need a preheater.- do not put sound attenuators. As a result, they complain about the loud operation of the supply and exhaust system.To help customers avoid such mistakes, we always try to give full consultation on the work of the ventilation system, with a detailed justification of each of its components.