To start, I know the basics of seasoning wood and we have plenty of seasoned wood. I know how to build and maintain fires, etc. I grew up with a wood stove, and my husband lived in a house with one for a while as a young adult, so many of the things most people don’t grok are old hat for us. Here’s our problem: the stove is installed properly and when we have a nice fire going, there is no smoke escaping into the house, even though the stove is the kind with removable plates on the top for cooking – there are a few gaps through which one might expect smoke to escape – but when the fire dies down, we get a crapload of smoke pouring into the house. I know the concept of draft is that the hot air (from the smoke) rises into the cooler outside air – but apparently that isn’t always working.
I should clarify. Everything is set up correctly, and we are not getting any blow back – it is only happening when the fire dies down and it becomes cool in the house. Does anyone else have experience with this and if so, what is the best way to deal with it?
We do. This is a cast iron stove – not one of those fireplace insert stlyes. It does have a fresh air intake on the door, which is left open enough to allow air flow.
Boxwood stoves like the one in your link are pretty inefficient and smoky in general, but here are a few suggestions:
Do you have a fresh air intake that draws air into the stove from outside of the house? If not (and to a lesser extent, even if you do), negative pressure inside the house will draw smoke out of the stove. I heat my house with a Jotul Oslo, and even with an intake from the outside of the house, we occasionally get smoke coming out of the stove if the bathroom fan is drawing air out of the house and the stovepipe is cold.
How tall is your chimney? Is it straight up? Does it end above the peak of the roof? Does it go horizontally through the wall and then up? Short chimneys that turn corners or stop short of anything around them will not draw well. Ones that go through the wall and then up cool quickly and you lose draft.
That’s what I suspected, but from her response, it seems it was not clear to Litoris.
One other thing I thought of last night:
Is the exterior portion of your stovepipe the double walled, insulated type? If it’s plain black stove pipe it will cool very quickly, and you will lose draft.
For optimum draft (assuming metal stovepipe), you want the pipe coming straight off the top of the stove and through the roof with no bends or reductions. The pipe should be plain black single-wall stovepipe to the ceiling, where it should attach to a metal box that both converts it to double-wall insulated pipe, and acts as a heat shield to keep the heat of the pipe from catching your upper floors/roof on fire. Outside of the house, the stovepipe shoud all be double-walled insulated, and should end at least 5’ (IIRC) above the roof peak or anything else within 20’ (IIRC). There should be a cover with a screen on top to prevent birds, bats, etc. from nesting in it.
If it’s an old installation - Did you check for obstructions in the stovepipe?
Just to check the obvious to make sure - On these stoves there is usually a damper in the stovepipe in addition to the air intake on the door for control. It looks like a sideways metal “T” stuck through the stovepipe with wire wrapped around the handle (top portion of the “T.”) If the top protion of the “T” is parallel to the stovepipe, it is open, and you’ll have better draft.
Thanks so much for the helpful responses. I was at work when I replied and yes, was a little confused about the fresh air intake. We do not have one on the chimney. Definitely something we are looking for now.
I will most definitely be replacing the single-wall exterior pip with insulated, I did actually assumed that it would be a good thing for that pipe to cool more quickly outside, helping with the draft. The roof peak is about 15’ from the pipe (everything we read said it should be 3’ higher than anything within a 10’ radius), so I think we are not having problems there. Again, this is only an issue as a fire dies down, and we are not getting any blow back while we have a good fire going.
Oddly enough, we didn’t have any smoke this morning, as the fire was dying down, so perhaps the stove was still tempering itself and correcting for cracks?
I am aware of the damper and proper use of it, but I understand the need to point out the obvious.
I will be taking the advice given and replacing the outside pipe soon, as well as looking for the fresh air intake for the outside. Because of the way the house was constructed, we cannot go through the ceiling, so it is out the wall and up – no way to change that.
Thanks for the help, guys!
My fresh air intake is like a clothes dryer vent on the outside wall, attached to an insulated duct. The plan is to attach the inside duct to a cold air return-like grill. I haven’t got that far yet so the duct is just open running parallel to the above joists.
Didn’t you need a building permit to ensure this is installed properly?
Do you have a CO2 detector? If not, please get one.
The fresh air intake is not for the chimney, it’s for the stove itself. On my stove, it’s a 3or 4" pipe like a dryer vent that runs through the wall behind the stove and into the bottom of the stove. Either your stove has a hole to mount the intake or it doesn’t - most likely not with one of those boxwood stoves. If not, there’s nothing I know of that can be done about it, it just means the combustion air has to be pulled in through all of the cracks around your windows and doors, making the house drafty and the stove more likely to smoke.
That 3’ higher than anything within 10’ is probably right, as I was going off my memory, and have an ever-increasing case of CRS.
I think you’ll be set if you replace the outside pipe with insulated. Be aware though, that your set-up is somewhat risky with the through the wall, then up configuration. Install a Tee with a cleanout instead of an elbow, and clean it out frequently. I think this is what you want, but I’d have to see it in person to be sure. Get one from your local wood stove supplier - they’ll know exactly what you need if you describe your set-up.
Never seen a vent like you describe. So you just vent that under the stove? What keep this from cooling your house when the fire isn’t sucking in enough air?
I think you mean carbon monoxide (CO) detector. If so, seconded heartily.
My wood stove does not have a cold air intake; many don’t. My building permit required that the room in which the wood stove was installed had a fresh air vent to the outside. Mine is at ceiling height. A four inch diameter vent doesn’t seem to let a lot of heat from the room escape.
Ok, we do not have the air intake thing. Since I have never had anything other than the boxwood type stoves, I guess that’s why I was confused. We have checked with codes and are in compliance. Not that that means much where we live this is the Middle of Nowhere, there are reasons I don’t let my kids go in the creek.
As for a CO detector, we have them, prior to the wood stove, we had propane heat.
Fortunately, this is TN, we won’t need to use the stove more than 3 months, but we will still be checking/cleaning the pipe regularly. This time next year, we hope to have a better chimney set-up installed as well as a better hearth area. We are also talking about getting a more efficient stove when they all go on clearance in March. We shall see. Again, thanks for all the help!
this is the Middle of Nowhere, there are reasons I don’t let my kids go in the creek.