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Positive Input Pressure Ventilation

A Positive Pressure System is an in-house ventilation system, also known as PIV or "Positive Input Ventilation." This is when the naturally warmed air from a roof cavity is drawn through a filter and into a fan that freshens the air and delivers it back into the home. PIV gently supplies tempered, filtered air back into the home using the heat from within the roof cavity and other warm internal spaces.

Through the PIV process the damp air is naturally pressurised and forced out, being replaced by the refreshed, healthy, filtered air from the fan.

The invention of these systems originated in the UK during the 1970’s; some of our products are sourced from Europe, however these systems have improved over time and due to similar building standards and environmental conditions, we also source our products from New Zealand, which have been proven and scientifically tested to significantly reduce air pollutants/contaminants and will improve the air quality in your home.

Positive Input Ventilation (PIV), or more simply, in-house ventilation, is very important in making your house a healthier place to live. The in-house air pollutants and moisture produced can contribute to an unhealthy environment. Evidence of this includes:

Everyday living activities contributes to these problems: heat from cooking, using the tumble drier, and taking hot showers (steam) all lead to moisture being produced and contribute to the household atmosphere. Aerosol sprays produce pollutants, and freestanding gas heaters produce water vapour (the main by-product of gas). We also give off an estimated 2 Litres of moisture (per person) from our own human bodies each day.

If you are producing or introducing moisture into your home, then mould can generate.

If you do live in a "damp" house, i.e. you have over 60% humidity levels/moisture content in the air, there is also the problem of dust particles being trapped and settling on moist surfaces, which then the mould spores will land on and can generate more mould.


Positive Input Pressure Ventilation gently supplies tempered, filtered air back into the home using heat from within the roof space.

Customers have commented on improvements in their previous health troubles with conditions such as asthma and respiratory infections, due to installing a system to improve the air quality of their home.

PIV systems have also been known to additionally benefit the customer by way of reduced energy usage (a net energy gain): using less energy to heat the dry air within your home, rather than heating the moisture particles in a damp house (which uses more energy.)

If you are experiencing any of the above, or want to learn more about us and our services, please contact us. We are delighted to provide an obligation-free quote, with your personalised home assessment and solution recommendations from the Ventilate Your Home team.