An opening with airflow controlled automatically by a mineral wool slab, avoiding undue draughts, with an effective area well above the minimum requirement for habitable rooms. Kitchens and bathrooms will generally require mechanical ventilation to cope with the greater amounts of moisture generated.

Air tested by the Building Research Establishment for airflow rates versus applied pressure difference.


  • No moving parts.
  • Works passively 24 hours a day.
  • Quiet operation (makes no noise).
  • Low installation costs.
  • Designed to fit 230 x 155 mm aperture (i.e. standard 9 x 6" airbrick).


  • Reduces draughty airflow and heat loss.
  • No running costs.
  • Works at peak condensation times.
  • No night time disturbance from compressors or fans.

General information


No moving parts

Works passively 24 hours a day

Quiet operation (makes no noise)

Low installation costs

Designed to fit 230 x 155 mm aperture (i.e. standard 9 x 6" airbrick)


Length (closed to extended): 240–340 mm

Uniclass 2015

Pr_70_65_04_28 External wall grillesPrimary


U90/34 Through wall ventilator ducts

U90/340 Through wall ventilator ducts

Specification data - External wall grilles

Product Reference

Passive Vapour Vents

Standard product features


Length (closed to extended): 240–340 mm.


206 mm.


136 mm.

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