Drafty Fireplace Causes
If you have a smoking or “drafty” fireplace, you may be surprised to know that the heating appliance itself is rarely to blame for drafting problems. Instead your fire is likely not burning right because the chimney is pulling combustion air improperly. Here’s where we must consider “chimney physics” and look at the big picture of the airflow in your home. The air in your house is constantly in motion; at all times there is air that’s trying to flow out of your house through the top and “makeup air” that’s trying to flow into your house through the bottom. When air flows up and becomes trapped, it creates a pressurized area and then forces its way out—a phenomenon known as “the stack effect.” There’s also what’s known as the “Neutral Pressure Plane” (NPP), a theoretical plane above which the air pressure is slightly positive as compared to the air pressure outdoors. Below the NPP (where the fireplace is usually located), the air pressure is slightly negative and trying to draw air in—thus smoke from your fireplace gets sucked into your home.
The flow of air inside your home can be interrupted and influenced by a number of factors. According to the Chimney Safety Institute of America (CSIA), the stack effect, wind loading, interior mechanical systems, and fuel-burning appliances like furnaces, fireplaces, wood stove, and water heaters, can all upset the airflow causing smoke to be drawn into your home when you light a fire. See what we mean about “chimney physics”?
With this in mind, an open window, a kitchen exhaust fan, or a recent home addition are just a few of the things that can impact draft and cause your fireplace to smoke. This is, by the way, the complaint we hear most often from our customers. Because smoky fireplaces manifest themselves in very noticeable and unpleasant ways, homeowners usually want to remedy the situation—and fast. That’s what A to Z Chimney Services is here for. You can call on us to detect the cause of your drafty chimney, and count on us to fix it for good.
For more on why your fireplace may be smoking and to read about common solutions to this problem, read our Smoking Chimney page.
Did You Know?
Homes built in the past 25 years, as well as homes that have been renovated, are more airtight and more likely to have drafty chimneys because it’s more difficult for makeup air to enter these homes.
Have a drafty chimney? Make an appointment with A to Z Chimney Services today. Email us at firstname.lastname@example.org or fill out our online appointment form! We’re here to help!
With a lot of experience under our belts, we can troubleshoot your chimney problem to diagnose what’s wrong with the performance of your fireplace or heating appliance. And then we can fix it for you.
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Everything from your company has been done in a professional manner! The person who came out to sweep my chimneys answered all my questions with pictures and a book full of before and after pictures of the most commonly needed repairs, and I was very impressed. Later on, you came back out to install chimney caps on both fireplaces. I was very please with all your work. And yes, when I need another chimney cleaning, I’ll definitely use A to Z again. You are professional and I give you very high marks!
~ Steve and Paula Nagrabske, Folsom, CA
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