A chimney cap is a protective cover placed on the top of a chimney. Its primary function is to prevent rain, snow, and debris from entering the chimney, which can cause blockages and damage. Additionally, chimney caps help to keep animals, like birds and squirrels, from nesting inside the chimney. Chimney caps also play a role in improving the efficiency of a fireplace or stove. By allowing smoke to escape while preventing downdrafts, they help maintain proper airflow. This can lead to better combustion and a safer, more effective heating system in homes.