FAQs

Chimney flue sizes

Most home owners may not know that each fireplace has it's own chimney flue. The chimney flue is sized based on the drafting requirements for the individual fireplace or heating appliance. If the fireplace is large, the flue is sized with a larger area. If the opening of the fireplace is small, the flue size should be smaller. Here is where it gets a little tricky. If your flue liner is too small, the flue will not draft properly and smoke will back up into the home. If your flue liner is too large, the smoke will travel up the chimney at a very slow rate. Creosote will form on the flue liner and will eventually clog the chimney flue. When this happens, either a chimney fire occurs or smoke back up into the home because the flue liner is clogged. Correctly sizing a chimney liner is a science. Chimney liners draft differently if it is round or rectangular. Other factors include, height of chimney, objects like trees that are near chimneys and other issues. The safest way to size a chimney is to use the IRC building code fireplace charts. If your fireplace is backing smoke into your home, a properly sized flue liner is a good start to prevent this problem. 

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