What to do if my woodstove smokes into the room?

Every winter about this time we are flooded with calls about smoking wood stoves.  Not smoking outside but smoke inside the home.  People will see smoke in the room when they start the stove, sometimes while the stove is burning, or when they open the door to load additional wood.  The first and easiest step is to blame the stove and think that something is wrong with the unit itself.  Wood Stoves are actually fairly basic appliances, even with all of the advancements in clean burning technology.  The unit burns wood, generates heat, and then sends the smoke up the flue to be exhausted outside the home.  When that doesn’t happen it is actually very rarely a problem directly with the stove itself.  The problem usually has to do with the flue system, the draft, or simply operator error when starting and maintaining the fire.

The first thing that you should check when you notice smoke back into the room is your chimney cap.  Chimney caps get clogged.  Even today’s clean burning EPA approved units get clogged.  Most chimney caps are equipped with spark screens to stop embers from getting loose.  On cold, wet, damp times the screen can become sticky and actually trap more than it should and act as a clog.  Wet wood, small fires, and damping the stove down to early can add to this problem.  We get tons of calls every year about smoke back into the house and the chimney cap is the first thing that we talk about and most times the first fix is the last fix.  Smoke is heat, it wants to go up and out.  If it gets to the cap half the battle is done, it is going up it just can’t get out.  Clean the cap and out it will go.

If it is not the chimney cap then most smoking problems are first associated with not establishing a good draft.   We recommend on a new clean burning wood stove or an older non approved unit customers “pre-heat” the flue before lighting the fire.  The chimney flue when the unit is not in operation is full of cold air relative to the temperature outside.  The colder the air the harder it is to push that cold air out of the flue to allow the smoke to be carried outside.  The initial smoke (heat) from the fire is not very hot and has a difficult time pushing cold air out sometimes causing at start up a back draft into the room since smoke wants to take the path of least resistance.  Once the draft is established the smoke will flow upward with issues.  Pre-heating the flue will eliminate that issue.  To properly pre-heat a wood stove flue customers should build their fire stack inside the stove as usual with paper, fire starters, kindling, or whatever your start up procedure is.  Before lighting the fire stack, keep a couple of pieces of newspaper nearby to roll up to act as torches.  Light the torches and hold them in the flue area of the wood stove.  The heat from the newspapers is very hot and will work hard to push the cold air out of the flue and establish the draft.  Once the heat from the torches is carried up the flue, then light the fire stack and see the difference.  Doing this will also lead to quicker heat into the room since the unit doesn’t have to waste any heat establishing the draft.

Lastly the chimney itself may be dirty causing a decreased volume or room for exhaust.  When this happens, like the chimney cap being clogged, smoke isn’t being fully allowed to leave the exhaust system.  Cleaning even a small amount of soot from the flue or baffle area of a woodstove can make the unit operate completely different than it did before it was cleaned.  Cleaning of woodstove should be done regularly.  There is no exact time to know when you should clean your flue and unit.  Most manufactures will recommend once a year.  Some people like to do it twice a year once at the start of the burn season and once at the end.  A good rule is to have the chimney cleaned every 2 cords of wood burned through your woodstove.

The stove is the easiest thing to blame, but rarely the issue.