What is loft-mounted positive-input ventilation?
In-loft PIV is installed in a loft space and is advertised as a ventilation solution for condensation, damp and mould.
The machine sucks air from the loft space through a filter and pushes it through ceiling vents into the living space.
Lofts are not designed as controlled environments. They are often exposed to airborne particulates and biotoxins including dust, mould, insulation fibres, rodent droppings, all of which can be drawn into the PIV system and delivered directly into the home’s living areas. An environmental change - such as a rodent moving in or a roof leak - can have an impact on the air quality within hours.
"Particles that can't be filtered pose the greatest health risk."
World Health Organisation
Why PIVs are not suitable for homes
As standard, in-loft PIV systems use G4 filters, which filter particles larger than 10 μm. Even the most effective PIV filters can only filter particles up to 1.0 micrometers (µm) in size, and therefore there is always risk of air contamination.
The World Health Organisation’s definition of the particles these filters cannot protect households from is: “ultra-fine or nano-particles that pose the greatest health hazard, as they can cross the alveolar-capillary barrier, enter the lungs directly via the bloodstream and consequently spread to organs, including the brain.”
HEALTH WARNING:
Loft-mounted positive-input ventilation
The Shepherds
The Shepherd family rented a council property in Devon. After reporting condensation issues - despite good heating and ventilation behaviours - the council instructed a third party property management company to install an in-loft PIV. The ventilation company they outsourced to didn't survey the loft, but went ahead and fitted the PIV. The loft space was mouldy due to water entering via the old leaking roof.
After a few weeks of the in-loft PIV being fitted and activated their youngest daughter - Elizabeth, aged 10 months, whose bedroom was next to the vent, became very sick and went into anaphylaxis and rushed to hospital.
Meet the people who found out the hard way...
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Louisa & Simon
"Everything we own became contaminated - we had to move and had nothing."
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Shelley & family
"Everything we own became contaminated - we had to move and had nothing."