It is not mildew we smell but the dry dirt itself we have lived here since 1983 and had no problem until we had air conditioning installed. Since then, only occasionally this occurs if away for extended periods and then only briefly once house is opened. This past spring we took insulation from floor and redistributed it around perimeter after listening to your program. At same time we put vapour barrier on floor. We were away over the past 5 days and upon return encountered strong smell of the dry dirt that seems to be lingering much more than usual. We recently closed all the vents and it has been unseasonably warm. Should vents be left open all winter?
Answer:
I'm afraid that's still the mildew that soaked into the wooden components over the years and you'll have to ventilate a lot more during the appropriate seasons to get rid of it. It will take time!