Positive Input Ventilation — The Ultimate Cure
Positive Input Ventilation (PIV) is the UK's most popular home ventilation strategy. Installed in over a million properties, PIV stops condensation and mould at the source by actively diluting moisture and replacing stale air.
A small, whisper-quiet fan unit is positioned out of sight in your loft space. It takes fresh air from outside via the loft space, filters it through medical-grade particulate filters, and gently pushes it down through a central ceiling diffuser into your landing or hallway.
This air supply creates a very slight, imperceptible positive pressure inside your home. Humid, stale air is naturally forced out through window vents, door gaps, and structural micro-openings. Within days, your home's air is clean, fresh, and dry.
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The Science of Condensation & Mould
Modern homes are built to keep heat in—meaning double glazing, wall insulation, and draft excluders trap humidity inside. Activities like drying laundry indoors, cooking, and showering add up to 10-15 litres of water to your home's air daily.
When this moisture-laden air hits cold surfaces like window panes or external walls, it condenses back into liquid water. This constant dampness creates the ideal breeding ground for toxic black mould spores.
PIV tackles this dynamic directly:
- Displaces Moisture: Damp, humid air is pushed outside before it can settle.
- Thermal Dilution: Dry air from the loft dilutes the absolute water content.
- Constant Circulation: Prevents "dead air" pockets in corners and wardrobes.
By keeping relative humidity consistently below 55%, mould cannot survive or return.
