Creosote is a major issue for any household or commercial wood burning fireplace. Creosote seeps into mortar joints and small cracks in the flue system as it turns from a gas to a liquid to a solid and corrodes away the inside of your flue. During very humid times of the year, creosote in the chimney can start to stink up a home as well. This being said, it is recommended to have the chimney swept when there is 1/8″ of creosote buildup. To prevent corrosion of your flue system and odor problems from occurring, you will want your chimney sweep to be able to remove as much creosote as possible and as completely as possible. By utilizing creosote removal products a month or so prior to calling out your chimney sweep you will increase the effectiveness of the sweep.
With so many creosote removal products on the market, it may be difficult to pick just one. With similar pricing and technical specifications, one way to decide what type of creosote removal product to purchase would be to research application methods and choose one that you feel comfortable with. There are powdered creosote modifiers and liquids, removers that you apply up in the flue system itself and removers that you apply directly to logs in the fireplace. You need to make sure that the type of creosote removal product you purchase is intended for use in the type of fireplace that you have, whether it be a wood burning fireplace or a fireplace using gas logs, and that you are comfortable applying the product.
If you have a wood burning fireplace, you have many creosote removal products to choose from. A few that I would recommend would be Cre-Away or Anti-Creo-Sote (ACS) by
ChimneySaver. ChimneySaver has an entire line of products formulated specifically for use on chimneys from heavy duty water repellents intended for use above the roofline where the elements hit the hardest to flexible crown repair products to repair small cracks that often appear over time at the top of the chimney. Cre-Away Creosote Modifier is one of their products that is actually a powder. It is effective on all types of creosote (glazed or loose) and actively reduces the odor that creosote in the chimney produces by neutralizing. This neutralizing aspect reduces the corrosiveness of the creosote while its still resting in the flue and allows your chimney sweep to remove creosote more completely and more easily. You apply this product directly p into the flue system by squeezing and aiming up the chimney. The application of the product directly into the chimney allows for it to modify glazed on creosote, which is normally very difficult to impossible to remove, and chemically alters is to a more sweepable form. Cre-Away Creosote Modifier is sold in 1 lb. bottles and it is recommended to use 1/3 of a bottle on each fire that you burn prior to having your sweep come.
A different product by ChimneySaver is Anti-Creo-Soot, or ACS. This spray bottle is effective on creosote because it is a liquid manganese catalyst, catalyzing the breakdown of creosote. You can use the product on almost anything: boilers, fireplaces, pellet stoves, furnaces, wood or even coal burning stoves. Due to its chemical makeup, it actually insulates appliances, improving heat transfer. The product is safe for use on catalytic combustors so long as it is put into bypass mode before treatment and for an hour afterwards. You can purchase this product in 32 oz. spray bottles or 1 gallon refill containers and should use about twelve sprays on the inside of the firebox, on the wood, and up in the flue in order for it to be effective. For severe creosote build up, up to 60 squirts can be used daily for the first seven days of use. ACS also comes in a powder and is applied directly to the flue instead of the fire. By using ACS Powder after every cleaning you will reduce the acidity and odor of creosote. Similar to Cre-Away Creosote Modifier, use about 1/3 of the bottle with each use.
If you have gas logs in your fireplace I would recommend using the ACS Gas Log Carbon and Soot Remover. It disperses carbon and soot deposits that have accumulated on the gas logs with only a light mist. This product does not damage the logs. You mist the logs when they are burning hot. I wouldn’t recommend using this product on light colored logs due to the fact that the manganese catalyst may cause yellowing to occur.
Creosote removal products such as these aren’t going to make the creosote in your chimney vanish, but it will enable the chimney sweep who comes out to remove the creosote to remove it more completely.