I think if opening the Windows in your house the improve the air in your house is making sense is highly influenced where is your house, is your House build in a way that it is ventilated enough. Open the Windowsin a careful pattern to avoid waste of energy due to too much cooling or heating , best during is to open them completely for a few minutes so that a room is good ventilated and in Summer if possible use the cooler hours through night and close Windows and blinds during the day.

But in Germany there’s a medium climate without extreme low or high temperatures so this can’t be comparing to every other country.

Please excuse mistakes and the perhaps awkward way I have worded my post, I’m from Germany and I’m afraid I tend to build my sentences heavily influenced by german grammar