A constant supply of fresh air, regardless of the weather

VELUX Ventilation flap
Home ventilation design
VELUX ventilation solutions
Roof ventilation design

VELUX balanced ventilation – using the natural air flow

Keep your indoor environment enjoyable with a stable, draught-free flow of fresh air through the flap, regardless of outside weather conditions.

  • Constantly adjusts airflow through the ventilation flap according to wind pressure.
  • Optimises the standard ventilation flap by allowing more air through the flap in calm weather and less in windy weather.

  • Completely self-regulating ventilation unit that doesn’t require mains or battery power.
  • Ventilation unit is discretely integrated into the top of the window - completely invisible from inside.

VELUX smart ventilation – using heat recovery

With VELUX smart ventilation heat recovery unit, you get an incoming flow of fresh air through the flap, heated by the warmth of the air that’s being drawn out – giving you fresh air while keeping the room temperature stable.

  • VELUX smart ventilation recovers more than 75% of the warm exhaust the air that is being drawn out.
  • Ensures a constant air exchange, even during calm and wind-free days, giving optimal indoor climate in any weather.
  • Increases your indoor climate without unwanted draughts or increasing your heating bill.
  • The VELUX smart ventilation unit is easily installed with a new window and is invisible from inside the home

VELUX ventilation - Roof ventilation

Your family and your home will greatly benefit from background ventilation, which helps you maintain healthy indoor air. Use the VELUX ventilation flap or our ventilation units to ensure a flow of fresh air throughout the day. And because the window remains closed, you can even enjoy background ventilation through the flap when you are asleep.



Concentration Situation Symptoms
400 ppm Natural level None
600-800 ppm Well-ventilated dwelling None
1150 ppm Acceptable level for a closed room Symptoms for asthmatics begin
1150 ppm Recommended as maximum level by the Active House class ll principles  
1150-2500 ppm Poorly ventilated living room, unventilated bedroom, airtight house Yawning, drowsiness and dizziness
5000 ppm Upper limit for continuous exposure Fainting possible
10000 ppm Brief exposure only Nausea, vomiting and fainting

Ventilation facts