How to Fix a Chimney Fireplace Smoking Problem

There is nothing worse than spending time to get a fire roaring in your fireplace only to have a room filled with smoke moments later. Smoking problems are a major complaint amongst many home owners. There are many different ways to go about fixing this problem, but you must have patience. Sometimes the answer is simple, other times it’s more complex.

Cold air is much heavier than warm air. The warm air should rise out of your chimney, including the smoke produced. If your flue system is not warm when lighting the fire then you can alter the ability of the fireplace to draw properly, creating potentially harmful smoking problems. A warm air siphon must be created before a fire can burn properly and draw correctly.

Tip #1: Crack a window

The quickest and easiest tip to creating a good draw for your chimney is to crack a window in the same room you are lighting the fire in. This will bring pressure into the room, causing air to be drawn up the chimney and allowing the smoke to move upwards and out, not into your living room.

Tip #2: Pre-heat with some newspapers

Pre-heating your flue system is another quick and easy tip to getting a roaring fire. Rolling up five or six newspapers and lighting them in the fireplace will help to warm up the flue and create a good siphon. This process may take five or ten minutes but can be critical to having a properly drawing fireplace. Also, make sure your damper is propped wide open or the smoke won’t be able escape.

Tip #3: Install a Smoke-Guard

smokeguard

Smoke-Guard

If these quick fixes are still not helping your situation, you may need to look into some more expensive but effective solutions. One of the easiest of these is the Smoke-Guard. If your firebox is too big for your flue system, more smoke can accumulate in the firebox than can safely draft up the chimney. The excess smoke has nowhere to go but back out into your house. Install a Smoke-Guard, a strip of metal to increase the size of the opening of your chimney, can immediately solve smoking problems. This makes the ratio of the fireplace opening to the flue size more compatible.

Here’s how to tell if your fireplace opening is too large for your flue:

  1. Determine the area of your flue. If it is rectangular or square, multiply the flue’s length by its width. If it is a round flue, use the radius (half of the diameter.) Multiply 3.14 x radius x radius.
  2. Determine the area of your fireplace opening. Multiply the height of your fireplace opening by its width.
  3. Compare them. If the area of your fireplace opening is more than 10 times the area of your flue, your smoke problems may stem from your fireplace opening being too large for your flue. A smoke guard will effectively reduce the size of your fireplace opening.

Tip #4: Extend your chimney

If your chimney does not extend high enough above your roof line, or there are nearby trees or other flue systems, this can cause competition for proper drafting. Negative pressure can build up into a tightly sealed home very quickly, which means that the air pressure outside the home is greater than inside the home. If the chimney is not tall enough, air and smoke can easily enter the home to fill the discrepancy between the two pressures. Extending your chimney by a few feet can be costly but may be the only way solve a chimney smoke problem.

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44 comments on “How to Fix a Chimney Fireplace Smoking Problem

  1. Louise on said:

    Thank you SO much for the information provided on your site. We were totally baffled as to why the fire in our new house was filling our front room with smoke and now we have the answers.

    Keep up the good work.

    Thanks again.

    Kind regards

    Louise

  2. Good info for one fireplace, but what do you do when the chimney shares two flues? In my home, when I start a fire upstairs, smoke comes out the fireplace in the basement. My house is built in the 50′s so I dont’ think that this is caused by the house being too “tight”. Anybody have any ideas other than always have two fires going at once?

  3. chimneyadmin on said:

    @Erick – I would suggest having a professional come out to your home and assess the pressure situation in your home. Even though your older home is more than likely providing enough air through tiny cracks in around the windows and doors, many different factors outside the home may be causing this smoking issue. If there are any tall trees located near your home, any hills, or if your home is at a relatively low height, negative pressure can occur.

  4. We have a stone fireplace that was built 8 years ago. At the time of construction the builder placed a
    steel firebox and heatalator system for wood burning use. After much trial and error we have learned
    that the flue was bullt too small for the unit. We have considered trying to convert to gas and using a line ( a
    five inch was successfully dropped in, but was tight). We are also considering removing drywall from the
    adjacent room (two story) and having the masonary flue tile removed and placing a double insulated
    stainless pipe system. Is this feasible/safe??? And would a system like this also contain a fresh air source?
    We also have problems with that area as well.
    Thans for your help!

  5. I HAVE A GAS FIREPLACE IN MY KITCHEN ABOUT 4 FEET FROM THE FIOOR. ON THE OTHER SIDE I HAVE A WOOD BURNING FIRE PLACE. WHEN I MAKE A WOOD FIRE MY FITCHEN FILLS UP WITH SMOKE. THEY DONT SHARE THE SAME CHIMMINEY, PLEASE HELP.

  6. our fireplace only smokes as the fire dies, as long as there is sufficient heat there is little or no smoke. Will a smok guard help with this situation or should we consider fireplace doors as a solution?

  7. There could be multiple causes for your smoking problem. Lets try and address a few of these.

    You may need to get your calculator out for this one, but the flue may actually be too small for the fireplace. To operate properly the flue size (not damper size) opening should be no less than 10% of the square inches of the mouth or opening of the fireplace. If you need a smaller fireplace opening, thats when a smoke guard will help.

    Another culprit is that exhaust fans in a kitchen or adjoining room could be pulling the smoke back down the chimney. Stairwells and tall ceilings can act like a powerful drafting chimney and could actually be pulling air down your fireplace chimney.

    I’m not a big fan of draft inducing chimney caps, as they are an expensive gamble that may or may not work in your case. Glass door have never resolved a smoking problem for me! The problem with a sluggish drafting chimney is that when the fire starts to die down, the smoke starts to roll back into the room. This is the case especially when the room air temperatures drop, the furnace kicks on, and the cold air return start to pull air out of the living space.

    A little more food for though is that with all of our energy insulated homes is, they all need fresh air supplies to allow for the air replacement that is gobbled up in the wood burning process. The art of identifying negative pressures along with air balancing in our homes is affecting many of us today.

    Try opening a window a little. Then if that works, you may want to consider a larger outside air source for the fireplace. Trust me, it is all trial and error in resolving our negative pressures and air-balancing issues.

    Stay warm and safe
    Clay

  8. carrla stokes on said:

    We have vented propane gas logs in our fireplace and when we light them they smoke up everything. We have changed the oraface but still there is black smoke. What could be the problem?

  9. askthechimneysweep on said:

    Gas logs are different between different manufacturers. Contact the manufacturer of your unit or the people who installed the system. You may also need to have the gas logs serviced by a professional; if the logs are not completely clean then debris on the log could cause the smoke when in use.

  10. I have another problem besides the smoke issue, my fireplace does not warm up the room. Infact the only way to feel any heat is to sit on the fireplace step.

    If the smoke problem was fixed would this fix the heat problem?

    Many thanks
    Tony

  11. Bill N on said:

    Looks like there’s some info that might help me here, but I want to be sure…so:

    This is my first winter in an old, 1920s built house. I cannot see up the chimney, as in my prior houses, due to what I believe is called an offset. The back wall of the fireplace angles inward, and then up, where the damper opens. Pretty impossible to see up. It also doesn’t seem that there would be the same air flow up, as my prior two fireplaces had.

    Ok….so my first supply of firewood, I couldn’t even get to burn. I figured it wasn’t as “seasoned” as they said. Got some different wood, and same problem. I worked harder at getting it too lite, the next time, and voila! I got a real good fire, that burned for 4+ hours.

    Suddenly, my smoke alarms started going off all the way up on my 2nd floor. And, you could see the smoke building in the fireplace room. I started opening windows, but it wasn’t helping. It got worse and worse, and I had to put out my fire.

    I was very perplexed by this, being the fire burnt so well for so long, then suddenly smoke. I do not believe it was warmer outside than in, as it is in Michigan and it was about 4 in the afternoon in late Oct.

    I have yet to start measuring, and I’m not even sure I can measure my flue, as I can’t even see up it.

    Any thoughts?

  12. chimneyadmin on said:

    My first thought is to call in and experience professional chimney sweep, and only one that uses video inspection camera equipment.
    Do not rule out that you may have experienced a chimney fire.
    I would suggest looking by zip code on the National Chimney Sweeps Guild list at http://www.ncsg.org Thermo-syphoning problems could be and issue, if upstairs fans or the furnace were to come on. But I would find this all very unusual after burning successfully for that four hours period that you mentioned.
    Burn safe and warm
    Clay

  13. I have another problem besides the smoke issue, my fireplace does not warm up the room. Infact the only way to feel any heat is to sit on the fireplace step.

    If the smoke problem was fixed would this fix the heat problem?

  14. Hi,

    I bought a 50-year old house, and noticed that my fireplace had a hole at the bottom, and this hole went through a wall and out side of my house. I had sealed this hole. My questions are:
    1. What was the purpose of the hole?
    2. Did I do the right thing by sealing this hole?

    Thanks,
    Kin

  15. I live in an air tight, 1200 sq/ft, two story townhome, (based on the 4th and 5th floors of a huge apartment complex). Our unit has a wood fireplace, encased with glass doors that extend to a metal cylindrical chimney. The chimney is capped by a metal spinny looking thing. My roommates and I held out for this place, specifically for the fireplace (we couch surfed for two months!). Alas, it has never worked properly. It rapidly smokes out the entire downstairs and twice the fire department has arrived. The landlord maintains that it wasn’t built correctly and there is nothing he can do. He said, “on the right day, it does work, just don’t expect it to work all the time”.

    Cracking a window DOES encourage the smoke to travel up the flue, but contrary to advice, the window must remain open the entire time the fire is burning…. and though it is only cracked, it somehow brings in so much cold air that it negates all warmth created by the fire and ultimately leaves the room colder.

    I live in San Francisco, CA. Today’s failed attempt at building a fire occurred during 54 degree outdoor temp and 68-70 degree indoor temp. The winds were moving west at 9mph.

    We really want the ambiance and warmth of a fire. Is there anything we can do? Thank you in advance for your help!

    Brrrr…. Freezing in the Fog.

  16. Great website.

    My corner fireplace always smoked and had since the house was build in the 50′s. Finally called a chimney sweep and he found a brick behind the damper that was preventing it from opening! Been that way from the day it was built. He chipped it off and the fireplace worked great! He also removed many “smoked” birds from the flue.

  17. If open fireplace will not draft because my recent built home with foam insulation is too tight, will I have the same problem with a wood burning insert

  18. chimneyadmin on said:

    These two issues do not go hand in hand. If you are looking for a significant heat source from you fireplace I would consider a woodstove. On a smaller note if you are looking to get a bit more heat out of your wood burning fireplace, I would look into purchasing a metal fireback. This will help radiate heat back into the room. So fixing a smoke problem is not going to fix a heating issue.

    Burn Safe and Warm

  19. chimneyadmin on said:

    Your very first statement is probably the problem. You live in an air tight space. This will cause the fireplace to starve for oxygen which in return will cause smoke to come back into the room. I say this because it sounds as though when you open a window it makes a difference. This sounds like it may be a imbalance of air pressure. Here are some simple things to check for: Is there a return vent for the furnace near the fireplace? Do you have high ceilings? You have a prefab fireplace and sometimes there is a vent. I would check just inside the doors for a small little finger lever. If you find one try and open it because this would be a fresh air vent. Other than that There are many other possible reasons for smoking problems. Call a Chimney Sweep for an evaluation, you can find one with our sweep locator.

    Burn Safe and Warm.

  20. chimneyadmin on said:

    Most likely no, but there is no guarantee. To often people underestimate air pressure in a house. Draft problems can be caused by many different factors so again no guarantee. Also if you are considering an insert you have to make sure it is lined.

    Burn Safe and Warm

  21. chimneyadmin on said:

    It sounds like what you are describing is an ash dump. IF this is the case there is no problem with sealing the hole. However, if it was a fresh air vent it was designed to bring oxygen into the fireplace. If it is a fresh air vent, it may need to be opened to allow fresh air in while burning wood.

  22. Sapo the chimney guy on said:

    If the hole is in the front floor of the firebox it is most likely the fresh air vent, it if is the back floor of the fireplace it is most likely the ash pit access door, no problem closing the one in the rear by the back wall of the firebox however the fireboxes with the fresh air vent in the front of the firebox are mostly older construction.
    There could be at least 100 different reasons for a smokey fireplace some of them so obscure even a well seasoned chimeny sweep could miss it.
    It is important to take your time to trouble shoot a smokey fireplace.
    I like to look at it when it is not lit , then ask my customer if I can light it to watch the attitude of the flame /smoke,sometikmes it is as simple as Priming the flue because the particular chimney runs along the outside wall of the home and they’re trying to light a freezing cold chimney and it is blowing down so forcefully it is impossible to even light a match :) other times it smokes the entire time it is burning and that is no luxury for anyone in the home at all as a matter of fact that is very dangerous.
    I love that part of my job, I enjoy the challenge of fireplace smoking issues and solving them for my customers, they are always so grateful and that makes me feel good because I get extremely filthy sometimes and that does not make me feel good :) but it is what I do and what I have been doing most of my life and probably will be doing until my last breath, I love being a chimney sweep !

  23. Ron Wilson on said:

    We have two fireplaces on two floors. We just replaced the flue liner in the one we use on the second floor.We also put a cap on the chimney for the first time. Now, for the first time smoke comes into the room where the fireplace we don’t use on the first floor is located. Could the new cap be the problem, ( can’t get the flu liner installer to come back ).

  24. steve on said:

    Hi All..

    Have just moved in to 1700′s cottage, it has as expected a large open fireplace, we have tried a fire 3 times now and it just smokes us out!..it just cloads up and comes in to the room like an upwards waterfall!..
    I see whilst looking in to the problem that the flue may be too small for the size of the opening, however the chimney doesnt have a flue!!…just a large opening!…its not blocked, u can see straight up it!..
    Can anyone help so we can enjoy the fireplace ?
    Many thanks
    Steve

  25. Tori Hamilton on said:

    Hi there, great info on your website. We live in a sidesplit bungalow that we just moved into last spring so this will be our first winter. We have a fireplace insert that we have had swept and repaired (the chimney cap was cracked). Our roof has two different heights and our chimney is on the lower of the two and does not extend past the taller roofline. Our insert has two dampers, and even with having both open smoke comes billowing out as soon as we open the door. The glass is covered with smoke. We can see smoke coming from our chimney so it is drawing a bit. And our house is 33 years old and not sealed well. I was thinking we should be extending the chimney when we had it fixed but the chimney sweep and mason didn’t suggest it. Any other ideas? Thanks so much!

  26. As you stated, I would agree that the flue that your looking up is not properly sized for the fireplace and is to large at this point. A top of the chimney sealing damper can be installed to seal off the fireplace. Good glass fireplace doors work great but won’t keep rain and animals out of your cottage. Get some pricing from a chimney contractor on the “top sealing damper” and possibly some great insights on your smoking issues at the same time.
    Burn safe and warm!
    Clay

  27. I would pop the cap off to see if it is holding the smoke back! Thermo Syphoning could now be the problem if the liner is not sized properly(to same), or if the cap is acting in such a manner to curl the smoke back down the unused chimney. This unused fireplace flue could be “sealed off” temporarily or permanently with a top metal plate.
    Burn safe and warm!
    Clay

  28. ricardo teague on said:

    @Kin – hey i have the same thing in my fire placeits hole that goes out side ,and i have a problem with the smoke comeing back in the room ,so can any one tell me what to do

  29. We have a 1 year old insert that smokes every time we start it up. My wife believes that we have to use dura flames to prevent this, but I enjoy using real wood and do not believe that the type of heat source we are using should have any effect on the smoke that is created. Once the fire gets going, there are no issues. Any ideas on a solution?

  30. chimneyadmin on said:

    In most case it would be a house pressure problem! I have the same problem with a wood stove in my home.I open the patio door slightly and I use Dura flame fire starters. In about 2 or 3 minutes the kindling wood really gets going, then I close the patio door.I usually add on small pieces of wood in a tee pee pattern. Then we are off to the races.The really great news is, if I get the fire going my lovely wife enjoys feeding our woodstove fire for the rest of the night. I personally have found that good firewood for us is seasoned dry hard wood that has been cut, split and covered for about 6 months.
    Burn safe and warm
    Clay Lamb

  31. We have a 2-flue issue–when there is a fire in the upstairs fireplace, smoke comes back down through the chimney of the downstairs one, filling the room with smoke. We already put an extender on one of the chimney stacks, which was recommended to us, but it did not solve the problem. The damper on the basement fireplace more or less closes but does not seal completely; we were told it is pretty much impossible for it to close altogether. A chimney repair person suggested stuffing the downstairs chimney (we never use that fireplace) with insulation material, pillows etc. He said it is safe to do but I wonder. What do you think? Any better ideas?

  32. chimneyadmin on said:

    For energy savings and to stop cold air draft issue, over the 70 years homeowners have been blocking off their fireplace damper areas with insulation batting, metal tape and a whole host of other products. May I suggest investigating the product called “The Chimney Pillow and it’s possible benefits.

    Along with sealing the bottom off, the closing off of the top of the chimney flue with a metal plate may be another consideration.

    Their is another possibility and that is the flue tiles in both chimneys may be leaking through the seam where the flue tiles joins are. This mortared filled in area can deteriorate from water or possible may been dry stacked and no mortar was installed during the original home construction.

    Either way, this can be verified with a video camera inspection that most chimney sweeps companies provide. keep fight the smoking problem and evenly you will win

    Burn warm and safe

  33. I have a fireplace at a hunting cabin that has smoked since it was built over 40 years ago. We have made the fire place smaller, this helped some, cracking a window help at times, we raised the chimney 5 feet and this helped the most, but it still smokes at times, would going higher help any more? The original chimney was already 4 feet above the roof line.

  34. Julia on said:

    We bought a house in November. The first few fires were great, however the last few fills the house with smoke. Yesterday we had a chimney sweep clean, and last night the smoke was worse than ever. Why all of a sudden does the fireplace now not work?

  35. Hi!

    I am hoping you can help. I’ve had the fireplace inspected and cleaned yet the smoke detector goes off when I burn a fire with wood, if i do not leave a window cracked or am not constantly attending and stoking the fire (this is a recent development since the association extended and placed a cap on the chimney b/c the downstairs’ neighbor complained of smoke). Since the work has been placed, black smoke billows out my fireplace if i don’t tend the fire constantly. The association says there’s nothing wrong – amd are discounting the black wall above my fireplace.

    Tonight I burnt a dura log – the house smells bad (like chemicals) but the smoke detector didn’t go off and as far as I can see, there’s no smoke climbing up my wall… Thoughts?

  36. drian on said:

    hi, when I light my sitting room fire, the smoke comes down the kitchen chimney. the smell of smoke is unbearable! any remedies?
    also, in my mums house…if her neighbour lights his sitting room fire her bedroom fills up with smoke!!….help wanted please

  37. We have 2 fireplaces – 1 on main floor and 1 in basement. We have the same problem as mentioned by others that when we light a fire on our main floor, the basement gets smoked. A chimney sweep suggested we stuff the basement chimney , since we don’t use it, with fibreglass or we bought Roxul thermal home insulation and then close the damper and this should help with the smoke in the basement. This is a temporary fix until we get a gas furnace put in. Is this a safe option until we get $$ to put in the gas furnace?

  38. lloydlandry@gmail.com on said:

    Hi
    I “rigged” a temporary barrel stove in my garage and having some intermittent drafting probs. the pipe is at a 45 degree angle and goes out a window – there’s a section of double walled insulated pipe for the section that goes t the window. The flue to opening ratio is fine but I still get a little smoke out the front…

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