I have always noticed a damp, musty smell coming from our fireplace after wet weather. My parents also recently noticed that their wood burning stove smells during the summer months, but couldn’t quite figure out why.
Because of this I’ve done a load of in-depth research into why our family has experienced strange odors coming from our fireplaces and wood stoves, and I’ve put together this complete guide on why a wood burning stove or fireplace would smell.
I’ve found that many of the reasons why a fireplace or stove smells are very similar, and so this article will be relevant to you whether you have a wood burner or a traditional open fireplace.
Why Does My Wood Burning Fireplace or Stove Smell?
In the large majority of cases, the wood burning fireplace or stove itself won’t be the cause any unusual smells. There are many other factors that can influence how well your fire burns and how well your fireplace or stove works, all of which can contribute to a fireplace or stove that smells.
Unusual smells coming from your wood burning fireplace or stove are typically a result of a problem with the wood or due to having insufficient draft, which can prevent any moisture, smoke or gases from leaving your home. A poor draft can be the result of a blocked chimney or flue, poor ventilation to the fire, or even the weather conditions.
Each element of having a fire in a wood burning fireplace or stove can play a role in why it would smell. These can include the type of wood that you’re using, the condition of the stove or fireplace, the size and height of the flue or chimney, and even the weather conditions.
Whether your wood burning fireplace or stoves smells, during use or not, I’ve put together the top 16 reasons why your wood stove or fireplace has an unusual odor.
The Stove Is New
Each newly fitted wood burning stove will require a ‘break in’ period before they can reach their optimum efficiency at providing heat to your home.
The number of fires required, and their requirements for the size and length of the fire, will differ between each manufacturer. Refer to your stove manufacturers’ guidelines and recommendations on how to break in your stove.
During the break in period of your wood burning stove you may notice a chemical smell, which can be a result of the paint curing on your stove as it’s being used the first couple of times.
This is perfectly normal for any stove, and if you’re noticing a chemical smell from your new wood burning stove then there shouldn’t be anything to worry about. Keep using your stove to complete the break in period and the smell should subside.
The smell comes from the evaporation of the liquids when the paint is curing at high temperatures.
In general, it will take three to four uses of your stove for it be broken in and the chemical smell to disappear.
You may notice that your stove continues to produce this smell, which may be caused by other parts of your stove system still curing (particularly the flue). Consult the manufacturer or installer of your stove if this curing smell continues over time.
Too Much Smoke Being Released By The Fire
A common cause of a wood burning fireplace or stove smelling can be when the fire is releasing too much smoke.
Smoke can be released from a fire when the fuel isn’t being burnt properly; in this case it’s the wood. Fire needs fuel and oxygen to survive, meaning that too much smoke from the fire can be due to either an issue with the wood, or with an issue with the supply of air to the fire.
There are a number of factors that influence how well wood burns in a fire, but logs can burn poorly and increase the risk of smoke being produced if the moisture content is too high.
Burning Wet Wood
Burning wood that has too high moisture content can be a common cause of a wood burning fireplace or wood stove smelling.
It can be very inefficient to burn wet wood. The optimum moisture content for wood to be burnt is 20% or less.
Above this number, the higher the moisture content, the more energy is required by the fire to burn off the excess water. This excess moisture content needs to be burnt off before the fire can burn the wood properly to produce heat.
Burning off the excess moisture can cause the fire to produce smoke, which in turn can result in the fire releasing soot and creosote up the chimney or flue. Soot and creosote can build up on the inside of the chimney or flue and leave a lingering smell coming your fireplace or stove. The excess moisture that is burnt off from wet wood can also line the insides of your chimney or flue and cause a musty smell.
In order to reduce the smell caused by excess moisture, soot and creosote, be sure to only burn well seasoned or kiln dried wood. Wood with moisture content of 20% or less is recommended to help prevent the release of smoke and other particles from a fire.
Burning Polluted Wood
This may sound like a strange one, but a number of people have reported that they’re getting strange smells from their fireplace or stove as a result of burning wood that has soaked up residual fumes from vehicle exhausts over time.
This was from wood that had been stored in garages to dry out. If you’re continuously using wood from the top of stacks in your garage then you may not have yet encountered this issue of polluted logs causing a strange smell.
The problem may occur if you start using logs from the bottom of the pile that have sat for extended periods of time, and have been regularly exposed to exhaust fumes.
If you are experiencing a unusual smell from your wood burning stove or fireplace, try burning wood from a fresh new batch and see if the smell disappears.
If you find that polluted wood is the reason behind a smelling wood stove or fireplace, a solution to this can be to use continuously use up the whole stack of wood so that it doesn’t sit for extended periods of time in contact with exhaust fumes. This would be instead of only taking the top layer of wood and never using logs from the bottom layers of a stack.
Storing the logs in another location in your home outside of the garage may be the only way to prevent the wood from soaking up exhaust fumes from your vehicles.
Also be sure not to burn any chemically treated or painted wood as these can also release harmful toxins into your home.
The Fire Isn’t Burning Hot Enough
Wood burning stoves have optimum operating temperatures that help to maximize the amount of heat provided to your home.
Higher fire temperatures are required initiate ‘secondary burn’ of waste gases to provide even more heat output.
A wood stove operating at sub optimal temperatures is more likely to produce smoke from the fire, which in turn can cause the stove to smell.
Check your manufacturers recommendations on operating temperatures for your particular model of stove.
To help increase the heat of the fire in your stove, be sure to only use dry wood and allow for sufficient airflow through the stove vents.
The right size fires should also be built and maintained within the stove. A fire that is too small for the size of the stove will not bring it up to optimum operating temperatures, while continuously building fires that are too large for your stove can cause permanent damage to the stove over time.
Blocked Chimney or Flue
A dirty chimney or flue can smell, and an unswept chimney or flue can also prevent smoke and gases from properly leaving your home, causing your wood burning stove or fireplace to smell.
Burning wood releases soot and creosote that can build up within your chimney or flue over time. As mentioned earlier, burning wood with high moisture content can increase the rate of build up of soot and creosote as the fire will smoke more than usual.
Soot and creosote itself has a distinct smell, and any downdraft within your chimney or flue can spread the smell of both of these into your home.
A chimney or flue lined with soot and creosote will also in effect reduce the size of its opening, and will therefore be much less efficient at drawing air from your fireplace or stove compared one that has been recently cleaned.
Smoke and gases from the fire can be prevented from leaving your stove as a result of a dirty chimney, and can be another cause of why your wood burning stove or fireplace smells as the smoke and gases aren’t being properly exhausted from your home.
A blocked chimney or flue can also be caused by birds nests or other debris such as leaves and moss.
Be sure to get your chimney swept if you haven’t done so within the last year in line with recommended guidelines.
Insufficient Chimney Size
An undersized chimney in relation to the size of your fireplace or stove can reduce its efficiency at removing waste smoke and gases from your home.
In general, taller chimneys provide a greater draw to your fireplace than a shorter chimney.
An undersized chimney can be a reason for ongoing smoke smells from your stove or fireplace. A chimney extender can be used to provide the required length of chimney to ensure sufficient suction to your wood stove or fireplace.
A chimney also needs to extend a certain height above surrounding rooflines. Any surrounding buildings to your home that are higher than your chimney can cause downdrafts in high winds due to turbulence.
Taller isn’t always better though, as hot air from a wood burning stove or fireplace can cool down and lose its momentum before reaching the top of the chimney.
Just as burning excess moisture from wet wood can leave moisture within your chimney or flue, wet weather conditions can also cause a musty smell coming from your fireplace or stove.
Rain can make its way down into your fireplace and leave moisture lingering within your flue or chimney. This can be especially a problem when no chimney cap is installed at the top of the chimney.
Wet weather can also make any soot or creosote deposits within your chimney or flue smell worse.
If you notice a musty smell from your fireplace or wood burning stove, note down whether the smell is caused by wet weather conditions. If you notice the smell occurs after wet weather conditions, you can be confident that it is being caused by excess moisture within your flue or chimney. It might also be a sign that your chimney or flue is dirty and needs cleaning.
Excess moisture from wet weather can also make its way down into your stove and potentially cause damage your stove or damper is left untreated.
We don’t have a chimney cap and notice that the fireplace in our living room can have a musty smell after periods of wet weather.
Getting a chimney cap installed should help remove any problems and smells cause by excess moisture within your chimney. We’ll be looking to do this soon!
If the outside temperature is lower than usual, it may be preventing smoke and gases from leaving your home properly.
Since cold air sinks and hot air rises, cold air within your chimney can prevent byproducts of the fire in your wood burning stove or fireplace from efficiently leaving your home.
If this is the case, it’s always worth ‘priming the flue’ by holding a heat source near the opening of the flue in your stove or the chimney in your fireplace to warm up the air before having a fire. Lighting a scrolled up newspaper at one end and holding it under your chimney or flue for 30 seconds should be sufficient.
This will help increase the draw of air from your stove or fireplace and help prevent lingering smoke and gases in your home.
If your chimney is located on the exterior of your house then you may find that this issue can be more common than chimneys that are located internally.
Just as cold air can prevents byproducts of a fire from leaving your home, windy weather can force air back down the chimney and cause the same issues.
If you’re using your wood stove in windy weather, try using your stove in calmer weather and see if that resolves the problem of smells from your stove.
Special chimney caps can be installed to help prevent downdraft of air during periods of high winds.
Insufficient air supply to your stove or fireplace can be a common cause of a why a fire is smoking, leading to a fireplace or stove that can smell.
This can be more of an issue with stoves over fireplaces. Air vents on a wood stove can be opened or closed manually to help control the rate at which the wood burns.
If the vents on a wood burning stove aren’t sufficiently open, it can starve the fire of oxygen and lead to excessive smoke production.
To prevent this, keep the primary vents on a stove wide open when starting the fire. The vents can be then be partially closed to control the fire. If the stoe vents are closed too much then the fire can be starved of air and start producing smoke as a result.
Every wood burning stove is different and it can be a learning process to understand how best to use the vents to control the rate the wood burns.
Too Much Ash
For both wood fireplaces and stoves, too much ash can cause reduced airflow. Ash left for too long without being cleaned out can also start to smell.
It’s recommended that only a couple of inches maximum depth of ash is needed at any one time. Too much ash and the fire can be smothered due to insufficient air supply.
While the ash should be maintained periodically to keep the amount to a maximum, it should also be cleaned out every so often to prevent smells from ash that has sat too long.
Try to think of your wood burning stove or fireplace as a passageway for air from the inside of your home to the outside.
The air that’s being sucked up your flue or chimney needs to be replaced by further air from the room. If there is insufficient ventilation within your home to replace the air sucked being out, negative pressure can be created and will reduce the draw on your fireplace or stove.
Insufficient ventilation within your home can therefore cause your wood burning stove or fireplace to smoke and prevent the smoke from leaving your home, which in turn can lead to lingering odors.
Negative air pressure in your home can be made worse by having a newer, tightly sealed home, or where there are extractor fans also sucking air out of your home, such as in a bathroom.
To overcome this issue, leave any doors to the room open. If this doesn’t solve the issue, open any vents within the room or leave a window on the bottom floor of your house open a few centimeters.
There’s A Hole In The Flue
A hole in your flue can leak smoke and gases from your wood burning stove.
This is more likely to be a cause if your stove has recently been installed or is of old age. It can be quite hard to figure out if and where your flue is leaking, but should be an easy fix for any professional.
A dead animal in your chimney or flue may be the reason for any unwanted smells.
Over the last year we’ve had two pigeons make their way down our chimney; one into the fireplace in the living room and one into the fireplace in the kitchen.
We board up the fireplace in the kitchen over the warmer months when neither fireplace is being used. A pigeon had fallen down into this fireplace and I noticed a scratching noise in the kitchen one evening.
It seemed as though the pigeon had been in there for a while, and we may have never realized until there was a nasty smell coming from the fireplace.
So yes, dead animals can certainly be a cause for unusual smells from a wood burning stove or fireplace!
If you have a damper that is closed or partially closed, it can prevent waste gases and smoke from leaving your fireplace or stove.
A damper will usually be located at the base of your flue on a wood burning stove, or located at the top of the firebox or at the top of the chimney for open fireplace.
Be sure to keep your damper wide open when starting the fire. Leaving the damper wide open for the duration of the fire will also help prevent any smoke being produced and potentially leaking out into your home.
The damper can then be closed when the fire and the coals have fully cooled down, to help prevent any smells from the chimney or flue from coming into your home when your fireplace or stove isn’t in use.
Why Your Wood Burning Stove or Fireplace Smells
The first step to identifying why your wood stove or fireplace is to understand whether the smell is ongoing and constant, or situational.
Situational causes of odors from fireplaces or stoves can include:
- Burning wet or polluted wood
- Having a fire in wet, windy or cold weather conditions
- Not clearing out the ash often enough
- Not providing enough ventilation to the fire
- Leaving the damper closed or too far closed
- Using a new stove
- Not having a hot enough fire for the size of the stove
- A dirty or blocked chimney or flue
- Dead animals
Ongoing reasons for why your fireplace or stove smells includes:
- A chimney or flue with insufficient height
- Having a chimney or flue diameter that is too small for the size of the fireplace or stove
By starting with situational causes and moving onto potential ongoing causes, you can help to narrow down the reasons for any unusual smells from your wood burning stove or fireplace.
How To Stop Your Wood Burning Stove From Smelling
– If your wood stove is new, use it for a couple of times to get rid of any paint smells
– Burn only low moisture content well seasoned or kin dried wood
– ‘Prime’ the flue or chimney before using your stove on colder days by warming up the air with a heat source
– Try not to use your stove in windy weather
– Fully open the damper within your flue or chimney during a fire, and close the damper in between fires to help prevent any ingress of odors into your home.
– Install a chimney cap to prevent rainwater ingress into your chimney and stove or fireplace, or to reduce the problems of downdrafts in windy weather
– Ensure adequate ventilation for the room, whether it’s by opening internal doors to other rooms or opening windows and vents to the outside.
– Have your chimney swept at least once per year.