What protective measure does a chimney cap provide?

A chimney cap serves an essential role in protecting the chimney and the spaces connected to it. Specifically, it helps to keep moisture and debris out of the chimney. Moisture can lead to the deterioration of the chimney structure and potentially cause issues such as rusting of metal components or damage to brick and mortar. Debris, such as leaves and twigs, can also obstruct the flue, leading to dangerous conditions like chimney fires or carbon monoxide buildup in the home.

While the other options may seem relevant to chimney function, they do not accurately describe the primary protective measure provided by a chimney cap. For instance, while a chimney cap may indirectly affect draft strength or help mitigate backdrafts, its main function is to guard against the intrusion of water and debris. Insulation is not the purpose of a chimney cap; that falls under different chimney components or thermal protection methods. Therefore, the correct understanding highlights the importance of the chimney cap's role in protecting the chimney from environmental elements.