In both cases there is comfort but I find that with controlled residential ventilation with heat recovery there is less comfort, many write about disturbing noises, sometimes inappropriate humidity, and what I see as the biggest negative point is the pipes through which air is conducted, where germs can form that can never be completely cleaned again. Economically speaking, I am not quite sure that the variant with heat recovery is better, since initial investment costs, maintenance costs, electricity costs and replacement of defective devices must be considered here. Is the variant with heat recovery better for the environment? At first one says yes but the manufacture and installation of the instruments and materials involved in heat recovery also require energy, the operation of these devices is not possible without electricity. When considering all these things, one can really say whether heat recovery is environmentally friendly. After research and considerations I have decided on the simple variant, i.e. without heat recovery.