Do I have to do forced ventilation in my home?
There is such a term as breathable walls, there is a term of vapor permeability and water tightness and these are absolutely different concepts. And if we are talking about whether ventilation is necessary, it is primarily human health.
A healthy person needs 30 cubic meters of fresh air per hour, for us to get that amount of air and it cannot be obtained through breathing walls when you have air leaking through the cracks the building will incur insane energy losses and for this ventilation is needed and to ensure the level of CO2 in the room. If we are talking about analogous ventilation with open windows, it is impossible to gauge on your senses when the right comfort temperature is reached, especially in the winter.
If we use ventilation with recuperation we get fresh air just cheaper, but ventilation is necessary to provide the right balance of CO2 indoors in an energy-efficient house and if we don't do it, we use systems with automatic window opening, but they cost more. Ventilation is your health, if you don't have ventilation it will be stuffy indoors and if you put the numbers up to 890 we are ok with CO2. For example, in schools we reach 3500 CO2 in public institutions 2000 quietly.