In a mechanical ventilation system, you have grilles above the windows that provide a constant supply of fresh outdoor air. The ventilation valves connected to the mechanical ventilation system ensure the removal of polluted air via the exhaust ducts. To ventilate effectively and continuously, it’s especially important never to turn off this mechanical ventilation and to keep ventilation grilles always open.
Do you keep grilles or windows closed?
Then you run the risk of creating negative pressure in the house, causing air to be drawn from places where it shouldn’t come from. Examples include openings at pipe penetrations, crawl spaces, open heating appliances, or water heaters.