A door brush bottom, typically made of bristles set into a durable backing, is designed to create a seal at the lower edge of a door. This simple yet effective solution serves multiple purposes. Primarily, it acts as a barrier against drafts, dust, and pests. When doors are closed, gaps at their bottoms can allow cold air to spill in during winter and hot air to seep in during summer. This can lead to a significant increase in energy costs as heating and cooling systems work harder to maintain a comfortable indoor temperature. By installing a door brush bottom, homeowners can greatly improve their home's energy efficiency, resulting in lower utility bills and a smaller carbon footprint.