Modern mechanical ventilation systems are very effective because they run 24 hours a day, constantly bringing fresh air into ...

Fresh air intakes are controlled by dampers so the HVAC controller can open or close the vent based on the condition of the air in the house. Older units sometimes have only one outside intake, which ...

The classroom with the ventilation system peaked at around 1,500ppm ... which meant not enough fresh air was getting in. And that's bad news when it comes to preventing the spread of disease.