A seal affixed to the lower edge of an exterior door, typically made of rubber, silicone, felt, or foam, closes the gap between the door and threshold. This barrier prevents air infiltration, water intrusion, and pest entry.
Effective sealing significantly improves energy efficiency by reducing drafts, leading to lower heating and cooling costs. It also enhances comfort by minimizing cold spots and noise transmission. Furthermore, it protects against moisture damage, which can warp door frames and foster mold growth. Historically, simple materials like felt and rope were used for this purpose, while modern solutions offer improved durability and performance with materials like thermoplastic elastomer (TPE) and composite designs. Proper installation and maintenance are essential for maximizing these benefits.