Positive Input Ventilation is a process which dilutes, displaces and replaces unhealthy air in the homes with clean, fresh and filtered air. A 'Heater' model can used to preheat the air if required. The ventilated air is delivered into a landing or hallway, and then gently ventilates all other rooms directly off the landing/hallway.

Moisture can move around the home; this happens when opening a bathroom or kitchen door after bathing or cooking. The pressure caused by heat will spread the moisture to other areas of the home, which can lead to mould growth in habitable areas. 

It is unlikely to increase the pressure because even refurbished homes that follow the latest building regulations will leak air. The supply air from the PIV unit will normally introduce around 21l/s for a three-bedroom house however, it would typically lose around 30l/s. This means less air is being introduced to the property.

There are numerous leakage paths for air to escape from in the home; such as letter boxes, key holes, trickle vents in windows, cat flaps, gaps and cracks around doors, windows and floors.

With an ultra-low power consumption motor, the PoziDry Pro™ can service a two bedroom house for less than £13 a year.

The heater set point can easily be adjusted by the ventilation specialist installer. The unit comes pre-set at 5⁰C and can be increased up to 20⁰C when installed. The heater element heats up and transfers the heat to the incoming air. The cost to run the heater will vary depending on the requirements of each individual home and energy prices, which will vary depending on the energy supplier and tariff.

The Building Research Establishment (BRE) tested Positive Input Ventilation and concluded that compared to extract fans with the same flow rate, households could save up to a maximum of 10% of the space heating costs. Compared to extract fans, which only extract air from the home, PIVs are an energy efficient method of pushing out and replacing stale, unhealthy air with clean drier air. This is achieved by gently introducing filtered air into the home and increasing the circulation of air around the property. The BRE found that loft spaces are around 3⁰C warmer than outside; this is more energy efficient than bringing in air directly from outside.