A barrier installed along the base of a door, typically made of rubber, silicone, felt, or foam, seals the gap between the door and the threshold. This barrier effectively blocks drafts, moisture, insects, and dust from entering a building. For instance, a thin strip of adhesive-backed foam can serve this purpose for interior doors, while exterior doors might utilize a more robust, brush-like seal to withstand harsher weather conditions.
Effective sealing at the bottom of a door significantly improves energy efficiency by reducing air leakage, leading to lower heating and cooling costs. Furthermore, it enhances indoor comfort by minimizing drafts and stabilizing indoor temperatures. Historically, simple materials like felt or fabric were used. Modern materials offer superior durability, weather resistance, and sealing capabilities, contributing to a more comfortable and energy-efficient built environment.