What is the main purpose of a chimney cap?

The main purpose of a chimney cap is to prevent rainwater from entering the chimney. Rainwater can cause significant damage inside the chimney structure, leading to deterioration of the masonry, increased risk of corrosion of metal components, and the potential for mold and unpleasant odors due to moisture accumulation. A well-fitting chimney cap acts as a protective barrier that keeps water out and helps maintain the integrity of the chimney system.

While enhancing aesthetic appeal can be a secondary benefit of a chimney cap, its primary function is to protect against water intrusion. Preventing down drafts is also an important function, but it is not the main purpose of a chimney cap. Similarly, increasing chimney height is not a designed function of a chimney cap. Instead, the cap fits atop the chimney structure, offering protection from elements while ensuring that ventilation remains effective.