Today is Groundhog Day. If a groundhog sees his shadow, it signals there will be only six more weeks of winter weather. That's good. However, if you see a "shadow" in your home, it could be mold. Experts say the reason we hear so much about mold these days is because homes are increasingly being made airtight to save energy dollars on gas and electricity. Whereas this, in of itself, does not cause mold, airtight homes can, and do, trap moisture as a result of normal household functions like cooking, bathing, breathing and leaks -- from either plumbing or nasty weather. The result: moisture gets trapped inside and doesn't evaporate. It sets the stage for mold which can begin growing in as little as six hours. The answer is selective and controlled ventilation. Using kitchen and bath exhaust fans, attic fans or simply opening up a window sends pervasive moisture outside. Mold goes away! You won't see a "shadow" today, or any day for that matter.