How Often Should You Clean Your Chimney?

The short answer: at least once a year. But how often you should really clean your chimney depends on how much you burn, what you burn, and the type of appliance. Here’s how to know when it’s time.

The once-a-year rule

Industry bodies like the CSIA recommend an annual chimney inspection, and a cleaning whenever there’s enough buildup to warrant it. For most homeowners who use their fireplace through the winter, that means one professional sweep and inspection per year, ideally in late summer or early fall before the heating season.

It depends on how much you burn

• Frequent wood burning: if you burn most nights all winter, you may need cleaning more than once a season.
• Occasional use: a fireplace used a handful of times a year still needs an annual inspection, even if it doesn’t need a full sweep.
• Gas appliances: gas burns cleaner, but the flue and venting still need an annual inspection for blockages and corrosion.
• Pellet & wood stoves: these often need more frequent cleaning because of how they vent.

The 1/8-inch rule

A good rule of thumb: if there’s 1/8 inch (about 3 mm) or more of creosote buildup in the flue, it’s time to clean — regardless of the calendar. That much buildup is enough to fuel a chimney fire.

Signs you need a sweep sooner

• A strong, smoky or tar-like smell from the fireplace
• Poor draft or smoke backing up into the room
• Black, flaky soot or debris falling into the firebox
• You’re burning unseasoned or wet wood (it creates creosote fast)
• It’s been more than a year since your last inspection

Not sure where your chimney stands? An annual inspection is the easiest way to stay safe and catch small problems early.