Creosote sweeping logs can loosen the soot in your chimney, improving its performance—as long as they’re used correctly
Creosote logs keep a fireplace clean by loosening soot and creosote.
These logs are not a replacement for regular fireplace cleaning and inspections.
You should only use a creosote log once per season.
Fireplaces are a quintessential winter must-have, but that heartwarming time spent around the fire can make your space look less-than-pristine after heavy cold-weather use. Creosote is the filmy residue deposited in a chimney by burning wood. Not only does it look gunky and totally ruin your cozy aesthetic, but creosote deposits can also be a fire hazard—and they’re a big reason why a wood-burning fireplace needs to be inspected each year.
That’s where creosote sweeping logs come into play. These logs help clear the gunk by loosening creosote and soot, helping to make your fireplace a cleaner (and safer!) space.
If you use an open fire stove, fireplace, or wood-burning stove, chances are you’ve experienced the soot and other compounds building up in the burner’s chimney. These compounds accumulate regardless of what you use to make the fire, though poor airflow and greener or damp firewood increase the amount of smoke.
When the smoke condenses, it sticks to the insides of the chimney, producing creosote. This sticky, tar-like residue poses a fire hazard and is challenging to remove.
Creosote sweeping logs (CSL)—also known as creosote chimney logs, chimney sweeping logs, or just sweeping logs—help loosen the creosote deposits inside of your chimney. By burning a creosote log (just as you would with natural wood) in your fireplace, your chimney’s deposit can be cleared more easily, preventing unwanted buildup.
Creosote logs help with routine maintenance, reduce your likeliness of having a chimney fire, and are easy to use.
Keep in mind: Though creosote sweeping logs loosen the soot and creosote from your chimney, they are by no means a replacement for your regular chimney cleaning.
While it is important to routinely schedule professional chimney sweeps with a local pro, creosote logs are effective at maintaining a cleaner flue between cleanings, making them useful to have around.
Here’s how to use a creosote sweeping log.
The first thing you should do is ensure your home is safe and ready for burning a creosote sweeping log. Turn off all fans and your A/C or heater. Make sure that all ventilation systems on your stovetop or fireplace are properly installed, close off any lower air intake systems, and check that your fire protection screens are in place.
Before you light your sweeping log, it’s a good idea to prepare your fireplace by burning a wood fire first. This helps soften the unwanted compounds in your chimney and pave the way for the creosote log to work its magic.
If it’s been a while since you’ve used the fireplace, or if it’s been over a year since your last inspection, you’ll also want to get your chimney inspected before lighting that fire.
You don’t want to put the sweeping log directly onto an open fire because downdrafts can cause the smoke to be pushed downwards from the chimney into your home. Instead, wait for the fire to die down, and put the log on the embers.
For a small fireplace or woodstove, use one CSL. For a larger fireplace, you may need to use two CSLs. If you do end up using two logs, burn one at a time to prevent excess flames.
And, if a draft does happen, open some windows to clear out the smoke and ventilate the space.
You should only need to burn a creosote log up to once per season. These logs are not meant to be used regularly like normal firewood. It’s important to follow the manufacturer's instructions as overuse can potentially lead to chimney fires or other issues. Using them too frequently can also create excessive heat or cause other problems in the chimney.
If you’re worried about your fireplace performance, schedule regular fireplace cleanings and chimney inspections to maintain a safe and functional fireplace or wood-burning stove.
In short, yes. Homeowners should still get an annual chimney inspection whether or not they use the fireplace in a given year.
Soot and creosote aren’t the only things that can get inside chimneys when they’re not in use. Birds, branches, nests, and more can cause your chimney to need a good cleaning, and it’s not always obvious that a chimney is compromised until after burning a fire.
A professional chimney sweeper can identify and prevent any problems. Expect your professional sweeper to do a thorough inspection and clean your chimney in a way that leaves your home safe for having a cozy fire or cooking experience. They can also inform you of any potential chimney repair costs you may need to investigate.
The cost of a chimney sweep depends on the level of inspection and if you need to have any additional maintenance work. As it stands, it costs around $130 to $380 to hire a professional chimney sweep. For damaged or precarious chimneys, you might find yourself paying as much as $1,000 to $5,000 for a serious inspection.
You can clean a chimney yourself if there is minor buildup involved—say, soot on your smoke shelf or in the fireplace. But if there is extensive creosote buildup or you can feel a draft or see evidence of nesting by animals, it’s better to hire a professional chimney sweep. A pro can give your chimney a full inspection and recommend a course of action. Not cleaning your chimney fully and properly can result in chimney fires. Cleaning a chimney yourself is also messier than having a pro handle the project with the proper tools.
Yes, you need to leave your chimney damper open when burning a creosote log so that smoke and other debris doesn’t waft into your house as it’s burning. You’ll need to make sure your damper is fully open, even when the log continues to smoke, until it’s completely out and cold.
In general, it will take about 90 minutes to burn the creosote sweeping log by itself, allowing it to work its magic. This may be longer or shorter depending on the conditions of your chimney.
Yes, a hot fire can burn off creosote, and it’s recommended to start one before using a creosote log to heat up any stuck tar within your chimney. A creosote log can then cure and hopefully loosen creosote buildup.
