Chimney caps are recommended as one of the best, least expensive ways to prevent water penetration of the interior of a chimney. This important chimney component can also keep animals from moving into your chimney to nest and can stop hot sparks and burning embers from jumping out of your chimney to possibly ignite a fire on a roof, tree, or yard. However, did you know that chimney caps can also improve the draft in chimneys? Draft issues can contribute to smoky air and unpleasant odors entering your home as well as toxic gases like carbon monoxide lingering inside your chimney for longer than they safely should. Ashbusters would like to tell you more about how draft works and how a chimney cap can improve the draft by sharing with you some information from The Wood Heat Organization.
How does wind draft affect my chimney?
The higher the velocity of a stream of air, the lower is the pressure that it exerts on whatever it is flowing over. Just as wind gives an airplane wing a lift, wind flowing over the top of your chimney can increase draft because it makes a driving pressure which helps to pull exhaust gases out of the chimney. However, you cannot depend on this driving pressure to assist draft because it is unpredictable. Wind can flow down in the direction of the chimney after passing over an obstacle like a roof, trees, or an adjacent building. Wind can also get to the top of a chimney from below after passing the roofline to the chimney at the peak. Wind tunnel studies have proven that if wind flows from either above or below the chimney top, it can create positive pressure at the top of the chimney that can negatively affect the upward flow of exhaust gases out of the chimney. When this happens, you can experience chimney draft problems like smoky, smelly air and poisonous carbon monoxide entering your house.
How can a chimney cap improve draft issues?
If your chimney has no cap installed at its top, you are the most vulnerable to chimney draft problems. Simple, flat chimney caps are better than no cap at all; however, to improve draft issues, you need a chimney cap with baffles to prevent direct lines of slight access to the opening to protect you from the adverse effects of wind. Chimney caps with baffles can improve chimney draft no matter from what direction or speed the wind approaches the chimney. This type of chimney cap has a design that consistently creates a driving pressure at the top of the chimney to help pull the byproducts of combustion out of your chimney and home.
Having draft problems with your chimney? Get in touch with us at Ashbusters to find out how we can improve the draft by installing a new chimney cap on top of your chimney.