Always have a constant supply of fresh air, no matter how the weather is outside

With a VELUX balanced ventilation unit added to the roof window, the airflow through the flap is adjusted according to changes in wind pressure. VELUX balanced ventilation allows more air through the flap on calm days and less during strong winds, minimising drafts and boosting indoor comfort.

The innovative self-regulating ventilation unit, developed in cooperation with RENSON, is discretely integrated into the top case and works without any kind of power supply.

It’s totally unnoticeable from inside and will not obstruct your views or sunlight.


VELUX balanced ventilation at a glance

Fits both our top- and bottom-operated manual roof windows

The VELUX balanced ventilation unit integrates seamlessly with your VELUX roof window. You can upgrade your existing roof window or install a unit together with a new roof window.

The installation is a routine task for a professional installer or advanced DIYer.

Two ways to optimise a natural airflow throughout your home


Air flow performance (tested on a top-operated MK-size window)


Air volume flow [M3/h]
  Pressure difference [Pa]


VELUX balanced ventilation  VELUX standard ventilation flap
More fresh air in calm weather Less draught in windy weather

VELUX roof windows with VELUX balanced ventilation unit give best-in-class perfomance, boosting air flow to maximum in calm weather and reducing air flow to minimum in windy weather.


Technical data

  • Technical values for the VELUX balanced ventilation

The VELUX balanced ventilation unit is not compatible with VELUX INTEGRA® electric roof windows and manual awning blind MHL. Compatible with VELUX INTEGRA® solar awning blind MSL and solar roller shutter SSL.

Functions as a natural air inlet in combination with mechanical outlets - or on its own.