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Why Does My Chimney Stink?

Whether it starts suddenly or builds over time, an unidentified chimney odor can make your home uncomfortable and stinky. Instead of turning to air fresheners or scented candles, it is important to identify and repair the root cause of a stinky chimney. This helps to keep chimney odors from coming back, and it also improves the air quality in your home. At Clean Sweeps of Michigan, we want to help you learn some things that can cause your chimney to stink and how we can help with it.

What causes stinky chimneys?

masonry chimney on side of homeUnfortunately, there is not one hard and fast rule for what causes stinky chimneys. Different odors have different causes. Often, a chimney inspection is all you need to uncover the root cause of an odor. The following are four of the most common causes of stinky chimneys.


Odors associated with animal entry usually start suddenly. They are usually sharp or rotting odors and are often accompanied by the sounds of scurrying or scratching in the chimney. Birds, raccoons, and squirrels are just some of the animals that can – whether on purpose or an accident – become trapped in your chimney. Animal feces, food, drying nesting materials, or even dead animals can cause serious odors to overwhelm your entire home. In addition, they can carry bacteria, pests, and other microorganisms. Because of this, it is important to have animals professionally removed as soon as possible.


Creosote is a dark, sticky byproduct of fuel-burning fires that accumulates in the flue. While small amounts of creosote buildup occur with regular fireplace use, not having the chimney regularly swept or burning green or wet wood can cause extra creosote accumulation. Smoky or dirty smells are the result of hot or humid weather mixing with creosote buildup inside your chimney.

While the outside of the chimney is designed to withstand exposure to water, the inside is not. The presence of water in the chimney is often the result of a chimney leak. Leaky chimneys can cause dank, damp odors, as water has trouble evaporating in the cool, dark chimney.


In addition, water in the firebox or chimney can lead to mold or mildew growth, which can significantly negatively impact the air quality in the home. People with respiratory conditions such as asthma are at risk of health complications such as breathing issues when mold is present.


Drafting issues can cause smoky fireplace odors too. However, smells associated with drafting issues are most common on windy days – and when the fireplace is in use. Drafting issues are commonly caused by a flue that is the wrong size. If a new insert has been installed or if the fuel source of the fireplace has been changed, the flue may need to be relined to ensure proper draft.

Don’t let a stinky chimney ruin the air quality in your home. Instead, you should invest in fireplace experts at Clean Sweeps of Michigan today. Our chimney experts can provide you with more information on chimney odors or your next chimney inspection.

Chimney Odors

While relaxing in front of a roaring fire is meant to be relaxing, unpleasant chimney odors can dampen your enjoyment. Unfortunately, chimney odor can do more than just lead you to lighting a  Humidity and Your Stinky Fireplace- Boston MA- Billy Sweet Chimney Sweepscented candle; it can also seriously impact the air quality in your home. Because of this, chimney odors should be addressed as soon as possible in order to identify – and repair – the underlying cause of the smell.

What causes chimney odors?

Whether they are mild and barely noticeable or so severe they clear out the entire room, chimney odors are a serious fireplace problem. However, there is no one single cause for chimney odor; below are three of the many causes of stinky chimneys.

  • Animals: Even the smallest birds and mammals can cause major chimney damage – and major odors. Animal droppings, food, nesting materials, or deceased animals can all cause odors as well as expose your family to a variety of bacteria and diseases.
  • Wild animals: Even if the animal has passed away, should be treated with caution as they can carry disease. Chimney companies or wildlife rescue groups are good resources for removing animals as safely and humanely as possible. Homeowners should never attempt to smoke out an animal as this can kill the critters and cause potential chimney fires.
  • Creosote: Ignition of flammable creosote is the leading cause of chimney fire. This naturally occurring byproduct of combustion builds up in the flue when the fireplace is used; certain factors like using green firewood or allowing a fire to smolder can lead to additional creosote production. Because it is so flammable, creosote should be removed during annual chimney sweepings. If left untouched, creosote can cause smoky odors – especially during the hot and humid months of spring and summer.
  • Moisture: Even small amounts of water in the firebox or flue can cause damage – as well as chimney odors. In the dark and enclosed chimney, the presence of water from a chimney leak can lead to mold and mildew growth. In addition to creating a strong, musty odor, mold growth can negatively impact the air quality in your home; those with asthma, allergies, or other respiratory problems are particularly affected by mold or mildew growth in the chimney.

Resolving chimney odors

The best way to resolve a chimney odor is by identifying and fixing the underlying cause. Because there are a number of different causes of chimney odor, a chimney inspection  is often the most effective method of identifying the cause of the problem. In addition to finding the source of the chimney odor, chimney inspections can help identify any additional areas of damage that may need to be repaired.

Chimney odor can affect your home’s air quality – as well as the health and safety of your family. If your home is suffering from uncomfortable chimney odors, don’t delay; call Clean Sweeps of Michigan today to schedule your next chimney sweeping or inspection.

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