Wood-frame windows were once standard, but homeowners never appreciated the fact that, for looks and longevity, wood requires periodic painting or staining. Later, aluminum frames proved quite popular, thanks to their easy care and low cost. Being a highly conductive metal, however, aluminum does not insulate as well as wood. Fortunately, according to Jim Eldredge, a manager with Sears Home Services, there's one material that manages to overcome both shortcomings. "With the latest vinyl windows," Eldredge says, "you get thermal performance rivaling that of wood, and you get the low- or no-maintenance virtues of aluminum. It's really the best of both of worlds," he concludes.