The same is done traditionally in Italy and Spain, at least where and when the weather allows it (more in the south than in the north). In any case having the

The same is done traditionally in Italy and Spain, at least where and when the weather allows it (more in the south than in the north). In any case having the windows open for some time daily allows to change the air and it prevents moulds and similar, particularly in modern homes where windows and doors (and the actual building envelope) are airtight. Living in a recently built home with a good energy rating (please read as insulated and airtight) but without a mechanical ventilation system is - as I see it - a health risk, unless you adopt this traditional routine daily.