Your windows don't keep out the weather. Moisture can lead to rot, mold, and associated issues that undermine comfort and structural integrity. "Moisture is your home's greatest enemy," says Jim Eldredge, a product manager with Sears Home Services. If your windows no longer provide a waterproof barrier between indoors and out, pursue immediate repair or replacement. The windows themselves may have failed, or the problem may be due to improper installation. Want to avoid a future recurrence? Consider that windows from Sears come with a product warranty (view details), while the company stands behind its work with a Satisfaction Guarantee (view details).