White Bear Lake, Minn. —A family of new crawl space ventilation fans, called “UnderAireTM”, developed by Minnesota based-Tjernlund Products, offer homeowners a simple, easy and cost-effective way to mechanically circulate fresh outdoor air underneath homes and porches. Left untreated, high humidity in these enclosed areas can foster a myriad of structural problems including premature rotting of structural support columns, joists, floors and beam supports (increasing the potential for termite...