Note: Passyfier Vents are used as an aid to help control humidity and are NOT to be used as a method of providing ventilation to any gas, oil, or solid fuel appliance. The diffusion process is slow compared with mechanical ventilation and would not cope with a copious amount of

Input ventilation was found to be effective in reducing relative humidity levels by around 10%RH in the test house, even when internal doors were closed. Vapour pressures reduced overall by 0.2kPa. The unit was shown to be more effective upstairs than downstairs.

Energy-Efficient: Passyfier vents are incredibly energy-efficient, requiring no electricity to function. They rely on natural pressure differences instead, making them cost-effective and environmentally friendly. The moisture vapour pressure within a dwelling is always higher than the outside pressure therefore there will always be an escape of moisture vapour by the diffusion process through the Passyfier Vent. The first step in installing Passyfier vents is to determine where you need them. Passyfier vents are ideal for installation in areas habitable rooms, such as bedrooms and living rooms. Keep in mind that the vents should be installed at a maximum distance of 12 inches below the ceiling height.

The Passyfier Core 140 provides an opening on a section of wall normal to the airflow direction with an effective area well in excess of the minimum requirement. Airflow through the opening is controlled automatically by the intervening mineral wool slab and thereby avoids undue draughts. The diffusion process is slow compared with mechanical ventilation and would not cope with the copious amount of water vapour produced in a short time scale without the combined use of mechanical ventilation in kitchens and bathrooms.In the field monitored houses input ventilation was not consistently effective in reducing relative humidity. When internal humidity levels over those outside was examined, PIV was found to be effective in the most humid houses but did little in the dryer houses. Even in the cases where it was effective there were often inconsistencies between rooms in the same house. Passyfiers take advantage of the differential partial moisture vapour pressure that is normally higher inside an The Perma-vent passive air vent is environmentally friendly and requires no power, saving you money on your energy bills. It also has no moving parts and doesn’t require any maintenance. Passive Ventilation Products from Permagard