Chimneys need to be kept clean to prevent chimney fires, but how often they need to be cleaned is a tricky question. The National Fire Protection Association Standard 211 says, “Chimneys, fireplaces, and vents shall be inspected at least once a year for soundness, freedom from deposits, and correct clearances. Cleaning, maintenance, and repairs shall be done if necessary.”
In wood-burning fireplaces, creosote can build up and cause chimney fires. But even if you have a gas fireplace or don’t use your fireplace very often, you should have the chimney inspected and cleaned about once a year, as animals can get into the chimney and build nests, or leaves, sticks and twigs from nearby trees can become trapped in the chimney and cause chimney fires.
You could try to remove creosote and clean your chimney yourself, but for a thorough, professional job, you’ll need to call a chimney sweep. The cost is around $150 to $200, and you should make sure that the chimney professional does a thorough job. Ask for a Level 1 inspection; if the chimney sweep doesn’t know what that is, move on to another company. If you live in Canada, be sure that your chimney sweep professional is certified by Wood Energy Technology Transfer, Inc. (WETT).