Positive Input Ventilation

Tempered fresh air is gently introduced from the loft by a single fan unit through a ceiling diffuser mounted over the landing (or hallway, in a single storey dwelling). This filtered air creates a slight positive pressure, reversing the normal airflow. Air is now forced out of the building taking with it unwanted moisture, smells and pollutants. The incoming air collects solar gain from the loft and redistributes heat that naturally accumulates at the top of the stairs.

Operating quietly, the fan unit is automatically controlled to optimise condensation control and minimise running costs. This method of ventilation can be adapted to reduce radon gas levels within the building. It's very simple and economic to install and particularly appropriate for existing properties.

The disadvantages of Positive Input Ventilation systems are that in very air tight buildings there may not be enough ventilation so may require extract ventilation ports in wet rooms, these ports may have to remain constantly open. Desired PIV could be achieved but there is a risk the energy performance of the building could be compromised