You have not lit a fire in months, but every time the weather turns warm and sticky, a sour, smoky smell drifts out of the fireplace and into the living room. It is one of the most common warm-weather complaints we hear from Shorewood homeowners, and the good news is that a chimney odor almost always has a findable, fixable cause.
What actually makes a chimney smell
Chimney odors come from a handful of sources, often in combination. The most common is creosote and soot — the residue left behind by every wood fire — which gives off a campfire or tar-like smell. Moisture is the second big culprit: water soaking into the masonry and mixing with those deposits creates a damp, acrid odor. Then there are animals and debris. A bird, a squirrel, or a nest that got into an uncapped flue can rot and produce a foul, unmistakable stench. Each source has its own signature, and identifying it points the way to the fix.
Why the smell gets into your house
Here is the part that surprises people: the odor itself is usually not new, but the airflow that delivers it is. A chimney is supposed to draw air up and out. When your home becomes depressurized — bathroom and kitchen exhaust fans running, a clothes dryer pulling air, or the natural stack effect in a tightly built house — the flow can reverse. Air gets pulled down the chimney and into the room, dragging the smell with it. That is why odors are worst in humid summer weather, when warm, moist downdrafts are most likely. The smell is really a sign that your chimney is occasionally running backwards.
Getting rid of it for good
Masking the odor with a fireplace deodorant or closing the damper only hides the problem. The lasting fix starts with a thorough chimney sweeping to remove the creosote and soot that cause most smells. From there, a chimney inspection pinpoints whether moisture, a leaky damper, or an animal intrusion is also feeding the odor, so those can be sealed out too. A sound cap keeps rain and wildlife from getting back in, and correcting a strong household downdraft stops the flue from pulling smells indoors in the first place. Deal with the source, and the smell does not come back.
If your fireplace has been announcing itself on warm days, you do not have to live with it. Call Indigo Chimney Sweep at (815) 296-9565 or book online. We are bonded and insured, and we tell you the price up front. We will track down what is making your Shorewood chimney smell and clear it out at the source.
Frequently asked questions
Why does my chimney smell worse in summer?
Heat and humidity are the reason. Warm, damp air reacts with creosote and soot deposits inside the flue and amplifies their odor. Summer also brings the reverse-draft conditions that pull that smelly air down into the house instead of up and out.
What causes a chimney to smell in the first place?
The main sources are creosote and soot coating the flue, moisture getting into the masonry, animal or bird debris, and general buildup. Each has its own note — creosote smells like a campfire or tar, while animals and rot smell musty or foul. Often more than one is at work.
Why does the smell come into the room instead of going up?
It comes down to air pressure. When the house is depressurized — by exhaust fans, a running dryer, or the stack effect in a tightly sealed home — air can reverse and flow down the chimney, carrying odors with it. The smell is a symptom of that downdraft.
Will cleaning the chimney get rid of the odor?
A thorough sweeping removes the creosote and soot that cause most chimney odors, so it is the essential first step. If moisture or an animal problem is also feeding the smell, those need to be addressed too, which is why an inspection usually goes hand in hand with the cleaning.
Could the smell mean something is stuck in my chimney?
It can. A dead animal, a nest, or trapped debris produces a strong, foul odor and can also block the flue. A camera inspection finds the obstruction, and a properly fitted cap keeps animals and debris from getting in again.
Does a chimney cap help with odors?
Yes, indirectly. A cap keeps rain, animals, and debris out of the flue — three of the things that cause and worsen odors. Keeping moisture and nesting material out of the chimney removes the fuel for many smells before they start.
Is a chimney odor dangerous or just unpleasant?
Usually it is an unpleasant nuisance, but it is also a signal. A strong creosote smell means significant buildup, which is a fire risk, and a downdraft strong enough to carry odors indoors can also carry combustion gases. The smell is worth investigating rather than just masking.
How can I keep the smell from coming back?
Keep the flue clean with annual sweeping, keep water out with a sound cap and crown, seal a leaky damper, and address any household depressurization that causes downdrafts. Handle the source rather than covering it with air freshener, and the odor stays gone.
Written by Jamie Reed, operations manager at Indigo Chimney Sweep.
Published September 15, 2026