A PIV fan is a general-ventilation system that often sits in the loft, with a vent on your landing. A PIV pushes fresh air into the property, which forces the moisture laden air out of the property, before it gets the chance to absorb more moisture and condense on a cold surface, such as a window or external wall. In layman's terms, Positive Input Ventilation is achieved when you push fresh air from outside the property, into the property.
Nobody wakes up one day and says, "I need extra ventilation", without good reason. Ventilation systems are usually ordered to solve a problem, or to prevent a problem before it occurs. We can fix condensation throughout a property, poor ventilation and removing bad smells in kitchens and w/cs - we can't fix water ingress, leaks or rising damp with ventilation alone.
