What is the purpose of chimney wind caps?

A chimney wind cap prevents the wind from forcing smoke back down the chimney. A baffle cap is recommended to shield the chimney from direct wind exposure and optimize chimney performance.

Wind may improve ventilation by blowing across the top of a chimney, but wind blowing from above or below the chimney creates a positive pressure that inhibits smoke flow. If a home is located in a high-wind area, there are specially designed draft-increasing chimney caps that create stronger updrafts in stronger winds. Flat rain caps are also available but not as useful for wind management. Chimney caps in general are recommended to prevent animal nesting and stray sparks.