There's a growing environmental problem caused by energy efficiency and moisture. It's mold, both hidden and in plain sight, on and in walls, ceilings and carpets and any porous material that can absorb moisture and hold it until mold spores begin to grow. Why are we hearing about mold more than ever before? Because more homes today are sealed airtight. When small water leaks occur in a roof or somewhere in a home's structure and go undetected for a time, wet insulation and wallboard becomes a breeding ground for mold. To put mold on hold, reduce interior moisture and humidity levels with good ventilation and a dehumidifier, if needed. Catch and repair leaks early, and be aware that that condensation creates moisture problems, too. Watch for signs of mold, and act quickly to correct and prevent it. More important than being unsightly, mold is a health hazard. For more tips, visit our Web site at onthehouse.com. And that's the On The House tip for today.