In Finland, many people avoid opening windows altogether, and only rely on various devices for mechanical movement of air. I find it quite alarming actually, as many homes have stale air and subpar ventilation systems, always justified by "never let heat escape the house". The idea of opening windows to refresh the air in the house is basically alien to many Finns, while it's a normal thing to do in other countries; in German, there's a term Stoßlüften.
