Passive vents work because they have baffles to reduce noise and draughts. So they don't tend to get covered up by the resident.
But on their own they may not solve the condensation issue. You will need to deal with that with other ventilation and heating patterns. However, some properties are more susceptible to condensation so it may never be completely eliminated.
BTW, placing a hygrometer on the window cill, with all that condensation around is not going to give you an accurate reading of the property RH. In any case, humidity readings are irrelevant on their own. High humidity and cold walls will produce different effects to high humidity and warm walls, for instance.
Current thinking is that constant low extraction from a trickle fan (with boost) is more effective than fans going on and off at various times.
But on their own they may not solve the condensation issue. You will need to deal with that with other ventilation and heating patterns. However, some properties are more susceptible to condensation so it may never be completely eliminated.
BTW, placing a hygrometer on the window cill, with all that condensation around is not going to give you an accurate reading of the property RH. In any case, humidity readings are irrelevant on their own. High humidity and cold walls will produce different effects to high humidity and warm walls, for instance.
Current thinking is that constant low extraction from a trickle fan (with boost) is more effective than fans going on and off at various times.