Door usage and house settling will eventually wear down the sill seal on an entry door, but the Z-Series Articulating Cap Sill (ZAC) self-adjusts to stay tight. It’s made from a composite material that’s naturally springy, so it adjusts over time to maintain a firm seal. The product is paired with a matching sweep that fits on the door bottom. You can call one of Endura’s dealers to have it added to a new door, or you can retrofit it to a door that already has a nonarticulating Z-Series sill. Costs range from $6 to $12 for a standard 3-foot door.
Endura, 800/334-2006, enduraproducts.com.